Fanny E Hartmann
email: fanny.hartmann@universite-paris-saclay.fr

Using structural variants to understand the ecological and evolutionary dynamics of fungal plant pathogens

Keywords: Adaptation, Ecological and evolutionary dynamics, Fungal plant pathogens, Horizontal gene transfer, Inversions, Selection, Structural variants

Deletions, duplications, insertions, inversions and translocations are commonly referred to as structural variants (SVs). Fungal plant pathogens have compact genomes, facilitating the generation of accurate maps of SVs for these species in recent studies. SVs have been found to constitute a significant proportion of the standing genetic variation in fungal plant pathogen populations, potentially leading to the generation of accessory genes, regions or chromosomes enriched in pathogenicity factors. SVs are involved in the rapid adaptation and ecological traits of pathogens, including host specialization and mating. Long-read sequencing techniques coupled with theoretical and experimental approaches have considerable potential for elucidating the phenotypic effects of SVs and deciphering the evolutionary and genomic mechanisms underlying the formation of SVs in fungal plant pathogens.

I. Introduction

Fungal plant pathogens constitute a major threat to global food security and some natural ecosystems. Over the last decade, intraspecific comparative analyses and population genomics studies have aimed to elucidate the genomic basis of host specialization and local adaptation of fungal plant pathogens to both anthropogenic and natural ecosystems [START_REF] Fisher | Threats posed by the fungal kingdom to humans, wildlife, and agriculture[END_REF].

Most fungal plant pathogens have small genomes (< 100 Mb) with relatively few repeats.

Chromosome-level genome assemblies were successfully generated in major fungal plant pathogen species thanks to long-read sequencing (> 1 kb to a few Mb), which has greatly facilitated bioinformatic analyses relying on the availability of high-quality genome assemblies, such as structural variants (SV) identification [START_REF] Potgieter | On variant discovery in genomes of fungal plant pathogens[END_REF]. SVs are deletions, novel sequence insertions and duplications, leading to a loss or gain of DNA, and translocations and inversions, which rearrange DNA within the genome, affecting regions extending over a few nucleotides (typically at least 50 bp) to full chromosomes [START_REF] Abel | Mapping and characterization of structural variation in 17,795 human genomes[END_REF]. SVs may have major consequences, including incorrect allele exchanges during meiosis; they may be neutral or subject to selection, and may constitute a genetic barrier to gene flow at the onset of speciation [START_REF] Wellenreuther | Going beyond SNPs: The role of structural genomic variants in adaptive evolution and species diversification[END_REF].

Recent studies in fungal plant pathogens have revealed that SVs constitute a major source of genetic polymorphism within species, with a potential role in adaptive processes.

Remarkably, pathogens of agricultural systems were found to have a particularly large number of diverse SVs [START_REF] Langner | Genomic rearrangements generate hypervariable mini-chromosomes in host-specific isolates of the blast fungus[END_REF][START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF]. This brief review focuses on the shaping of fungal plant pathogen genome by SVs and the ecological and evolutionary importance of these variants. Promising avenues of research exploring the eco-evolutionary and genomic mechanisms underlying SVs in fungal plant pathogens are then highlighted.

II. The shaping of fungal plant pathogen genomes by structural variants

SVs may affect single genes or genomic regions of various sizes (Fig. 1), and recent studies have shown that SVs account for a large proportion of the standing genetic variation in both sexual and asexual fungal plant pathogens (Badet et al., 2020;[START_REF] Langner | Genomic rearrangements generate hypervariable mini-chromosomes in host-specific isolates of the blast fungus[END_REF].

Gene gains and losses (Fig. 1A,B,D,E) result in intraspecific gene content variation. They have been extensively studied in fungal plant pathogens, as they may lead to gains or losses of function, such as pathogenicity. The investigation of a fungal pangenome* (see Box 1 for definitions) using long-read sequencing (> 1 kb to a few Mb) from 19 strains of the wheat pathogen Zymoseptoria tritici, which frequently undergoes sexual recombination, showed that gene presence/absence polymorphisms occurred in 40% of the species gene pool, disproportionately affecting the effector* genes that modulate fungal pathogenicity (Badet et al., 2020).

Deletions, novel sequence insertions, duplications and translocations also affect non-coding DNA and transposable elements* (TEs) may be considered to be a type of SV (Fig. 1C; (Mérot et al., 2020b)). A population genomics study of TE dynamics in the mainly asexual fungal plant pathogen Verticillium dahlia revealed a high rate of TE insertion polymorphisms throughout the genome and a correlation between the presence of polymorphic TE insertions and the expression of pathogenicity-related genes [START_REF] Torres | Transposable elements contribute to genome dynamics and gene expression variation in the fungal plant pathogen Verticillium dahliae[END_REF]. A comparison of TE dynamics in several populations of Z. tritici showed that TEs may drive genome expansions over short evolutionary time scales [START_REF] Oggenfuss | A population-level invasion by transposable elements in a fungal pathogen[END_REF].

Losses, fissions, fusions and translocations of large regions have been identified in several fungal plant pathogens (Fig. 1F,G). These SVs may lead to the formation of accessory* regions, or even chromosomes. A study of SVs in four strains of the blast fungus Magnaporthe oryzae showed that accessory chromosomes probably emerged from interchromosomal translocations between core* and accessory* chromosomes and segmental duplications* of core* chromosomes [START_REF] Langner | Genomic rearrangements generate hypervariable mini-chromosomes in host-specific isolates of the blast fungus[END_REF]. These accessory* regions or chromosomes are often enriched in TEs, rapidly evolving genes, such as effector* genes, and various types of SVs relative to other regions of the genome.

III. Multiple eco-evolutionary processes in fungal plant pathogens are driven by structural variants

In addition to shaping pathogen genomes, SVs are directly associated with rapid adaptation and ecological traits in fungal plant pathogens.

Gene gains and losses may determine host specialization (Fig. 1A,B). Deletion of an effector* locus may enable the pathogen to escape the recognition by a host resistance locus in genefor-gene interactions. In the wheat stem rust pathogen Puccinia graminis f. sp. tritici, the loss of the AvrSr27 locus that is recognized by the major Sr27 resistance locus in wheat was found to arise independently in multiple field strains that became virulent on wheat cultivars carrying Sr27 resistance [START_REF] Upadhyaya | Genomics accelerated isolation of a new stem rust avirulence genewheat resistance gene pair[END_REF]. Gains of effectors* through horizontal gene transfer* underlie specialization on new hosts in the wheat pathogens Parastagonospora nodorum, Pyrenophora tritici-repentis, and Bipolaris sorokiniana [START_REF] Mcdonald | Transposon-mediated horizontal transfer of the host-specific virulence protein ToxA between three fungal wheat pathogens[END_REF] and in host-specialized Fusarium species [START_REF] Peck | Historical genomics reveals the evolutionary mechanisms behind multiple outbreaks of the host-specific coffee wilt pathogen Fusarium xylarioides[END_REF]. One intriguing trend repeatedly identified is the higher proportion of gene gains and losses in fungal plant pathogens from agricultural ecosystems than in fungal plant pathogens from forest or wild ecosystems.

Analyses of gene presence/absence polymorphisms in Microbotryum anther-smut fungi [START_REF] Hartmann | Gene presence-absence polymorphism in castrating anther-smut fungi: recent gene gains and phylogeographic structure[END_REF][START_REF] Beckerson | Cause and effectors: whole-genome comparisons reveal shared but rapidly evolving effector sets among host-specific plant-castrating fungi[END_REF] and in the chestnut blight pathogen Cryphonectria parasitica [START_REF] Demené | Whole-genome sequencing reveals recent and frequent genetic recombination between clonal lineages of Cryphonectria parasitica in western Europe[END_REF][START_REF] Stauber | Emergence and diversification of a highly invasive chestnut pathogen lineage across southeastern Europe[END_REF] have revealed very low frequencies of gene gains and losses in these pathogens. Various confounding factors may explain this discrepancy, including differences in pathogen population size and mode of reproduction, or environmental selective pressures (Badet & Croll, 2020). Regarding gene gains and losses associated to host specialization, the use of major resistance genes in host plants and the importance of arms race dynamics* in agricultural ecosystems may also result in pathogens being more prone to adaptive gene loss or gain. Conversely, the importance of quantitative sources of resistance and the trench warfare dynamics* in forests or natural ecosystems may favor alternative routes of pathogen adaptation [START_REF] Möller | Evolution and genome architecture in fungal plant pathogens[END_REF].

Additional striking examples of gene gains and losses linked to important ecological functions in pathogens include SVs affecting clusters of genes encoding proteins involved in secondary metabolite production (Fig. 1E). [START_REF] Zhong | Emergence of a hybrid PKS-NRPS secondary metabolite cluster in a clonal population of the rice blast fungus Magnaporthe oryzae[END_REF] reported a recent duplication of a secondary metabolite gene cluster containing an effector* gene in a clonal population of the rice blast fungus Magnaporthe oryzae [START_REF] Zhong | Emergence of a hybrid PKS-NRPS secondary metabolite cluster in a clonal population of the rice blast fungus Magnaporthe oryzae[END_REF]. Transposable element insertions have been shown to shape the genetic regulation of melanin production in the wheat pathogen Z. tritici (Fig. 1C, [START_REF] Krishnan | Transposable element insertions shape gene regulation and melanin production in a fungal pathogen of wheat[END_REF]). SVs have also been shown to be associated with very recent adaptation, as gene duplications have been reported to confer fungicide resistance within a few years in Z. tritici [START_REF] Steinhauer | A dispensable paralog of succinate dehydrogenase subunit C mediates standing resistance towards a subclass of SDHI fungicides in Zymoseptoria tritici[END_REF].

Recombination is often reduced at some SVs, particularly within inversions (Fig. 1H; [START_REF] Faria | Evolving inversions[END_REF]). The suppression of recombination due to segregating inversions may protect beneficial combinations of alleles against recombination events, in some cases leading to the formation of a supergene, i.e. a suite of genes inherited as a single unit that controls complex phenotypes. Supergenes are classically described in plants and animals to influence remarkable ecological or adaptive traits, and examples are emerging in fungal plant pathogens. Two inversions segregating between two host-specialized populations of the anther smut fungus Microbotryum in natural ecosystems, but fixed within populations, probably protected beneficial combinations of alleles and promoted population divergence in these plant pathogens from wild ecosystems [START_REF] Hartmann | Higher gene flow in sex-related chromosomes than in autosomes during fungal divergence[END_REF]. Chromosome fusions at centromeres or chromosome arm edges have been shown to have evolved several times in multiple host-specialized Microbotryum fungi. They maintain compatible combinations of alleles at two mating-type loci*, providing excellent examples of supergenes in fungi. The linking of the two mating loci* involved in mating compatibility in Basidiomycetes is beneficial in Microbotryum fungi which have high selfing rates, as it increases the odds of compatible gametes [START_REF] Branco | Multiple convergent supergene evolution events in mating-type chromosomes[END_REF][START_REF] Carpentier | Convergent recombination cessation between mating-type genes and centromeres in selfing anthersmut fungi[END_REF].

IV. Promising avenues of research using structural variants in fungal plant pathogens

IV.1. What is the impact of structural variants on fitness-relevant phenotypic traits?

Despite the identification of several adaptive SVs, the adaptive potential of SVs in fungal plant pathogens remains largely overlooked. The associations of SVs with a wide range of phenotypes or environmental variables (Fig. 2A) are promising tools for assessing the impact of SVs on fitness-relevant phenotypic traits. In a genome-wide association study (GWAS) performed in 106 Z. tritici strains, [START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF] showed that SNPs statistically associated with 16 life history traits overlapped with SVs. Remarkably, 14% of SNPs found associated with a fungicide resistance phenotype, overlapped with regions containing insertions or deletions, inversions or translocations, highlighting the importance to consider SVs more frequently in GWAS.

Genome engineering (Fig. 2B) is a powerful approach for functionally validating the impact of SVs on fitness-relevant phenotypes and was successfully applied in the yeast Saccharomyces cerevisiae [START_REF] Fleiss | Reshuffling yeast chromosomes with CRISPR/Cas9[END_REF]. Multiple translocations were generated in yeast with CRISPR/Cas9 technology. No point mutations were introduced with this method, so that it was possible to evaluate the effects of rearrangements specifically. The generation of translocations resulted in considerable phenotypic diversity, and conferred a fitness advantage in stressful environmental conditions, with the formation of unanticipated SVs, such as segmental duplications* [START_REF] Fleiss | Reshuffling yeast chromosomes with CRISPR/Cas9[END_REF]).

An experimental evolution set-up (Fig. 2E) in Z. tritici showed that greater chromosome instability occurs in heat stress conditions, with the fusion, fission or duplication of both core* and accessory* chromosomes, suggesting that SVs may serve as a response to stress in this pathogen. The overall effect of SVs on fitness was found to be small in this study, but complex, as it depended on both environment (in vitro vs in planta) and genotype [START_REF] Möller | Extraordinary genome instability and widespread chromosome rearrangements during vegetative growth[END_REF]. Theoretical modelling of the expected fitness effect of SVs in populations (Fig. 2C) may be a complementary approach to evaluate life-history trade-offs and would be interesting to be performed in fungal plant pathogens (Mérot et al., 2020a).

IV.2. What are the evolutionary forces driving structural variants in populations?

It remains unclear whether changes in the frequency of SVs in populations are mainly driven by selection or by neutral processes. A comparison of the population distribution of SVs versus neutral markers, such as SNPs, was performed in several fungal plant pathogens (Fig. 2D). It revealed that SVs can provide a global view of the population structure, with frequency differences observed between geographically and genetically isolated populations [START_REF] Hartmann | Gene presence-absence polymorphism in castrating anther-smut fungi: recent gene gains and phylogeographic structure[END_REF][START_REF] Hartmann | Higher gene flow in sex-related chromosomes than in autosomes during fungal divergence[END_REF][START_REF] Badet | A 19-isolate reference-quality global pangenome for the fungal wheat pathogen Zymoseptoria tritici[END_REF][START_REF] Stauber | Emergence and diversification of a highly invasive chestnut pathogen lineage across southeastern Europe[END_REF]. However, the differences between populations depended on SV type and differed from those observed for SNPs, suggesting differences in the underlying evolutionary processes. Recent gene losses and TE insertions present a significant excess of low-frequency variants relative to SNPs in the wheat pathogen Z. tritici, suggesting that strong purifying selection acts on these SVs [START_REF] Hartmann | Distinct trajectories of massive recent gene gains and losses in populations of a microbial eukaryotic pathogen[END_REF][START_REF] Badet | A 19-isolate reference-quality global pangenome for the fungal wheat pathogen Zymoseptoria tritici[END_REF]. Excess population differentiation has been observed for some SVs in Z. tritici and Microbotryum, suggesting positive selection [START_REF] Hartmann | Gene presence-absence polymorphism in castrating anther-smut fungi: recent gene gains and phylogeographic structure[END_REF][START_REF] Hartmann | Higher gene flow in sex-related chromosomes than in autosomes during fungal divergence[END_REF][START_REF] Badet | A 19-isolate reference-quality global pangenome for the fungal wheat pathogen Zymoseptoria tritici[END_REF]. Comparisons of empirical SV distribution with predictions from theoretical simulations (Fig. 2F) can help evaluating the relative effects of selective and demographic processes on SVs. The differences of mutation rates, allele numbers, population size and allele segregation at meiosis between the different types of SVs call for additional theoretical studies on SV evolution (Mérot et al., 2020b).

The role of allelic content and selection in driving SVs to fixation or maintaining polymorphism has recently been investigated in plants and animals in empirical and theoretical studies [START_REF] Faria | Evolving inversions[END_REF]. Fungal plant pathogens have diverse mating systems and life cycles, with haploid and dikaryotic ploidy stages of various lengths. It would be interesting to assess the effects of these features on the evolutionary trajectories of SVs, and to compare these trajectories with those in plants and animals. For example, it would be worthwhile investigating whether large adaptive polymorphic inversions or supergenes*, like those identified in Microbotryum fungi (see III.), have evolved frequently and independently in fungal plant pathogens and whether they contribute to rapid or ecological adaptation or whether most large SVs are deleterious. In addition to positive selection, non-adaptive divergence between arrangements of SVs, such as mutation accumulation, may also keep them polymorphic (Jay et al., 2021a;[START_REF] Berdan | Deleterious mutation accumulation and the long-term fate of chromosomal inversions[END_REF]. Simulations show that decreases in recombination at SVs may lead to the accumulation of recessive deleterious mutations and an increase in overdominance, due to less effective selection and stronger genetic drift [START_REF] Berdan | Deleterious mutation accumulation and the long-term fate of chromosomal inversions[END_REF]. A theoretical model has predicted the accumulation of inversions and other SVs around permanently heterozygous loci, such as the fungal mating-type loci*, as this permanent heterozygosity protects linked SVs against the expression of their recessive mutation load (Jay et al., 2021b). Interspecific gene flow was shown to play a role in the formation and evolution of SVs at supergenes in insects [START_REF] Jay | Supergene evolution triggered by the introgression of a chromosomal inversion[END_REF]. The role of introgression on the existence of SVs in fungal plant pathogen populations needs to be investigated.

IV.3. What are the genomic mechanisms generating structural variants?

SVs are often particularly abundant near centromeres [START_REF] Carpentier | Convergent recombination cessation between mating-type genes and centromeres in selfing anthersmut fungi[END_REF][START_REF] Cook | A unique chromatin profile defines adaptive genomic regions in a fungal plant pathogen[END_REF], regions with a high repeat content [START_REF] Faino | Transposons passively and actively contribute to evolution of the two-speed genome of a fungal pathogen[END_REF][START_REF] Peck | Historical genomics reveals the evolutionary mechanisms behind multiple outbreaks of the host-specific coffee wilt pathogen Fusarium xylarioides[END_REF][START_REF] Torres | Transposable elements contribute to genome dynamics and gene expression variation in the fungal plant pathogen Verticillium dahliae[END_REF][START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF] or regions with epigenetic marks contrasting with other regions of the genome, such as heterochromatin [START_REF] Cook | A unique chromatin profile defines adaptive genomic regions in a fungal plant pathogen[END_REF][START_REF] Soyer | Genome-wide mapping of histone modifications during axenic growth in two species of Leptosphaeria maculans showing contrasting genomic organization[END_REF]. Similarly, although the mechanisms of horizontal gene transfer* in eukaryotes remain poorly understood, a genome-wide survey of horizontal gene transfer* events in Verticillium dahliae showed that such events occur preferentially in repeat-rich regions of the genome [START_REF] Shi-Kunne | The genome of the fungal pathogen Verticillium dahliae reveals extensive bacterial to fungal gene transfer[END_REF]. The functional relevance of these features to SV formation within species remains to be determined. Ongoing improvements in genome engineering techniques and in the fine-scale dissection of epigenomic and repeat landscapes through long-read sequencing are likely to shed light on the interplay between these processes and SVs (Fig. 2G-2H).

In the fungus Z. tritici, the causes of SVs were recently studied by a pioneering approach that would be worth expanding both within this species and in other systems. A machine learningtrained model was used to predict the major SV events in a Z. tritici pedigree and to identify the principal genome features associated with SVs, in terms of base composition, gene density and retrotransposons, for example (Fig. 2I; [START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF]). In several meiotic crosses of Z. tritici, SVs were also found to be frequently located in close proximity to crossing-over sites. Analyses of rearranged chromosomes in the progeny of fungal crosses that can be readily performed in the laboratory are also a powerful resource for elucidating the mechanisms generating SVs [START_REF] Fouché | Meiosis leads to pervasive copy-number variation and distorted inheritance of accessory chromosomes of the wheat pathogen Zymoseptoria tritici[END_REF][START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF].

V. Conclusions

SVs shape the genomes of fungal plant pathogens, and there is increasing evidence to suggest that they play an important role in multiple eco-evolutionary processes in these organisms.

Current sequencing technologies are very promising for population-scale studies of SVs in fungal pathogens. However, there is a need to combine genomic analyses with more theoretical approaches predicting the effect of selective and demographic processes on SVs and experimental studies of the ways in which fungal genomes "cope" with such structural changes in terms of phenotypes, gene expression and fitness.

Box 1: Glossary. Terms defined below are indicated by an asterisk in the text.

Accessory: term that refers to genes, genomic regions or chromosomes not present in all individuals within a species / a population. Arm race dynamics: a theoretical model describing the evolution of effector* and resistance genes in plant-pathogen interactions in which a new allele providing a fitness advantage is under positive selection and is quickly fixed in the population of the pathogen or the host. Core: term that refers to genes, genomic regions or chromosomes present in all individuals within a species / a population. Effector: term that refers to genes or proteins encoded by fungal plant pathogen genomes and that modulate fungal pathogenicity on the host plant. Some effector proteins are recognized and interact directly or indirectly with host plant proteins. Horizontal gene transfer: exchange of genetic material between organisms often sharing an environment that is not vertically transmitted (i.e. inherited from parents to offsprings). It is also called lateral gene transfer (LGT) Mating-type locus: locus that controls mating compatibility in fungi based on molecular haploid nonself-recognition, mating being successful only between different alleles. Non-allelic homologous recombination: recombination event that occurs between highly similar but not homologous sequences (such as similar duplicated sequences or paralogous genomic segment) and may generate SVs. Segmental duplications: long DNA fragments (typically > 1kb) that have high sequence similarities and exist in multiple locations along chromosomes, tandem or interspersed. They result of duplication events and generate often SVs. Paracentric / Pericentric inversion: Paracentric inversion has breakpoint located on the same arm of a chromosome and doesn't include the centromere. Pericentric inversion has breakpoint located on opposite arms of the chromosome. and include the centromere. Pangenome: the full set of genes present within multiple individuals of a species, including core* genes and accessory* genes. Trench warfare dynamics: a theoretical model describing the evolution of effector* and resistance genes in plant-pathogen interactions in which a diversity of pathogen effectors* and host resistance alleles are under balancing selection and maintained in populations of the pathogen or the host. SVs in fungal plant pathogens are presented in blue circles. Green, orange and yellow rectangles refer to population genomics tools, experimental approaches and theoretical modelling methods, respectively, already successfully applied and that would be worth to be extended in several fungal plant pathogens. References related to examples of applications of these methods are cited in the main text or hereafter. A. Genome-wide association study (GWAS) look for significant relationships between genotypic variation and phenotypic variation and can give cues of the phenotypic impact of SVs. As illustrated by [START_REF] Badet | Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen[END_REF], SNPs may be used to test for associations and then coincidence with SVs can be investigated, or the association with SVs may be tested directly (Mérot et al., 2020b).

Figures

Environmental association studies that test for associations between SVs and environmental variables were successfully performed in plants [START_REF] Todesco | Massive haplotypes underlie ecotypic differentiation in sunflowers[END_REF] and would be worth expanding to fungal plant pathogens. B. Engineering of novel SVs in genomes and assessment of the SV fitness effect with in vitro petri dish assays or with in planta tests may help assessing the phenotypic impact of SVs. C. Theoretical modelling can be used to simulate and predict the fitness effect of SVs in populations. D. Long read-based genotyping of SV in multiple populations within a species and investigating population frequency differences of SVs and neutral markers may be indicative of neutral and selective processes on SVs. E.

Experimental evolution allow to study the apparition and evolution of SVs in controlled conditions and can be used to address the three major presented outstanding questions on SVs, as indicated by the dotted blue lines.

Figure 1 :

 1 Figure 1: Diversity of structural variants (SVs) and their ecological and evolutionary significance in fungal plant pathogens. (i) Several types of SVs, ranging from a few hundreds of base pairs to SVs encompassing larger genomic regions (>100 kb). (ii) Examples of eco-evolutionary significance of these SV types in fungal plant pathogens. From top to bottom panels: A. Loss of a single gene; B. Gain of a single gene. Gene gain and loss may be mediated via various mechanisms including nonallelic homologous recombination*, horizontal gene transfer*, or de novo gene evolution; C. Indel or transposable element (TE) jumps leading to gene expression changes. Changes in gene expression such as gene dosage or loss of expression may occur for genes located at SV breakpoints or in the vicinity of SVs; D. Gene duplication; E. Gain of a gene cluster; F. Translocations involving multiple chromosomes (interchromosomal) or along a chromosome (intrachromosomal); G. Fusion/fission of chromosomes. Major consequences of translocations, fusion and fission include linkage between previously unlinked loci, chromosome size variation and change in chromosome numbers; H. Inversions. Inversions may be pericentric* or paracentric* and recombination may be blocked between inverted haplotypes. Segregating inversion within or between populations may protect co-adapted allele combinations. References related to these examples are cited in the main text.

Figure 2 :

 2 Figure 2: Outstanding questions about structural variants (SVs) in fungal plant pathogens and pioneering approaches to address them. Major outstanding questions about

  F. Theoretical modelling can be used to simulate and predict the population genetics of SVs. G. Screening SVs distribution and frequency in genomes give insight in their occurrence with specific genome features, such as epigenetic marks. H. Engineering techniques allow to functionally validate the genetic mechanisms generating SVs. I. Modelling such as machine learning can be used to predict SVs.

Acknowledgments

This work was supported by ANR PIA funding: ANR-20-IDEES-0002 . Tatiana Giraud, Paul Jay, the anonymous reviewers and editor provided useful comments on the manuscript.


Romain Beaume

Rémi Maniak

Crossing innovation & product projects management: A comparative analysis in automotive industry

Keywords: organizational learning, new product projects portfolio, innovation management, automotive industry, comparative analysis

come

Crossing innovation and product projects management:

comparative analysis in the automotive industry.

INTRODUCTION

Projectification and platform approaches have been two main transformation trends for industrial firms in the 1990's and at the beginning of the 2000's. For those firms, innovation management no longer deals with introducing radically and totally new products, but more likely with applying innovative features within a stream of new products and platforms. This implies management of the interplay between the maturation of innovative features and the regular stream of development projects based on existing competencies. This paper proposes an analytical framework for a systematic comparison on innovation-product interplay management, and presents several early results based on data collected in the automotive industry. This sector provides an interesting empirical opportunity to study this question, since it faces a dramatic increase in the pace of launch both of new products and of innovative features.

We first present the empirical drivers of this research, set up the research question, regarding the important literature on project led organisation and learning. We then settle the theoretical framework and methodology for analysing the innovation/product interplay. In the third part we present five case studies, resulting from data collected in European and Asian carmakers. We finally present several lessons learnt from the comparison of these five cases.

1) MOTIVATION OF THE RESEARCH: THE NEW CHALLENGE FOR PRODUCT AND INNOVATION PROJECTS INTERPLAY

The current strategic context: renewing products more frequently while adding more radical innovative features

For the last 20 years, OEMs and suppliers have dramatically increased the pace of new products launches (Fig. 1). At the same time, OEMs launch more innovative features more often (Fig. 2).

As a direct consequence, automotive companies face an emerging challenge: to increase the frequency, reliability, radical nature, and profitability of the innovations developed in research and advanced engineering, and at the sale time to maintain their ability to develop more vehicles than ever in a context of very tight constraints on quality, cost and lead time.

Insert Figures 1 & 2 about here

Such a strategic challenge called for deep transition in car manufacturers product design processes in the last two decades.

The empowerment and routinization of product development activities in the 1990's

During the 1980's, the increasing competitive pressure put emphasis on the ability of industrial firms to improve Quality level, reduce Cost, Time-to market (so called QCT indicators) of new products, and last but not least, to manage the increasing complexity of products. Many industries addressed this shift: automotive, medical devices, consumer goods, and electronics.

Pioneer research defined concepts and organizational frameworks for effective "projectification" of product development processes: heavyweight project management teams, concurrent engineering and early supplier involvement [START_REF] Fujimoto | Product Development Performance. Strategy, Organisation and Management in the World Auto Industry[END_REF][START_REF] Midler | L'Auto qui n'existait pas: Management des projets et transformation de l'entreprise[END_REF][START_REF] Midler | Projectification of the Firm: the Renault Case[END_REF][START_REF] Wheelwright | Revolutionizing Product Development: Quantum Leaps in Speed, Efficiency, and Quality[END_REF]. Industrial firms implemented these frames and methodologies during the 1990's.

Nevertheless, this overwhelming success rapidly showed its bad side: the "fat-design" problem.

The focus on the QCT performance of a single product tended to favour one-shot solutions, developed specifically for one project, disregarding the firm global performance. To fight against this problem companies implemented platform strategies which relied on sharing components and subsystems among different products through a global part sourcing [START_REF] Cusumano | Thinking beyond lean[END_REF][START_REF] Lehnerd | The Power of Product Platforms[END_REF].

Given the increasing pressure on development performance, it became more difficult for firms to take risks in the context of development routines [START_REF] Aggeri | Innovation and project development: an impossible equation? Lessons from an innovative automobile project development[END_REF]. This led to "frontload" all the potential problems to the pre-project phase (the so called "fuzzy front-end" of the project). As a consequence, the pre-project phase more and more consisted both as a product definition process [START_REF] Reinertsen | The Strategist's Role in Shortening Product Development[END_REF][START_REF] Ulrich | Product Design and Development[END_REF] but also as a risk-elimination process aimed at reducing the problem-solving effort of the development phase [START_REF] Ciavaldini | Des Projets à l'Avant-Projet[END_REF][START_REF] Cooper | Winning businesses in product development: The critical success factors[END_REF][START_REF] Gerwin | An Evaluation of Research on Integrated Product Development[END_REF][START_REF] Thomke | The Effect of "Front-Loading" Problem-Solving on Product Development Performance[END_REF].

In the early 2000's, automotive firms were well armed to develop rapidly new products, and to have a global strategy for managing the diversity implied by this evolution. As a consequence, the gap among automotive OEMs around the world in product development performance has been narrowing in the 1990's [START_REF] Fujimoto | Shortening Lead Time through Early Problem-Solving: A New Round of Capability-Building Competition in the Auto Industry[END_REF].

Innovation management in the projectified firm

Although projectified organizations instituted core capabilities maximizing QCT indicators, these core capabilities tended to turn into core rigidities that modelled potential products through a stable architecture and existing competencies [START_REF] Leonard-Barton | Core Capabilities and Core Rigidities: A Paradox in Managing New Product Development[END_REF]. These organizations became reluctant to apply innovative features that were disruptive towards this organizational structure [START_REF] Galunic | Architectural innovation and modular corporate forms[END_REF][START_REF] Henderson | Architectural Innovation: The Reconfiguration of Existing Product Technologies and the Failure of Established Firms[END_REF]. Such results confirmed the results found out in the construction industry [START_REF] Mahmoud-Jouini | Exploring new proactive supply-based strategies the conditions on the project management of major french general building contractors[END_REF][START_REF] Lundin | A Theory of the Temporary Organization[END_REF].

Le Masson et al [START_REF] Le Masson | Les processus d'innovation: conception innovante et croissance des entreprises[END_REF] developed a general formalism to explore innovation reasoning, combining knowledge creation and concept development. Ben Mahmoud-Jouini and Midler [START_REF] Mahmoud-Jouini | Compétition par l'Innovation et Dynamique des Systèmes de Conception dans les Entreprises Françaises[END_REF] proposed a framework for exploring the interplay between product projects and learning processes within the design system of the firm, which articulates the product project management, the competencies creation process and the strategy formulation process. Learning processes imply pre-project research explorations and maturation, within project activities and from projects [START_REF] Blomquist | Learning from Renewal Projects: Content, Context, and Embeddedness, in Projects as Arenas for Renewal and Learning Processes[END_REF] by cross project comparison, formalisation and capitalisation processes [START_REF] Ayas | Professional Project Management: A Shift Towards Learning and a Knowledge Creating Structure[END_REF].

Iansiti's work [START_REF] Iansiti | Technology Integration[END_REF] improved our understanding of the linkage between technological knowledge activities and product development activities. He showed that development projects that "create a match between technological options and application context" perform better than others. In other words, knowledge creation carried out by research activities should be oriented toward the future contexts of application. Iansiti's work highlighted the technology integration process within a a new product, but remained focused on technical improvement, disregarding deeper reshuffling of the product hierarchy. Furthermore, the multi-product deployment of the technology remained at the background of his work.

Cusumano and Nobeoka [START_REF] Cusumano | Thinking beyond lean[END_REF][START_REF] Cusumano | Multi-Project Strategy and Sales Growth: the Benefits of Rapid Design Tranfer in New Product Development[END_REF] studied the management of new components roll-out in the context of automotive platforms . They show that the most efficient way to manage inter-projects linkages was to adopt a strategy of "concurrent technology transfer", a quick parallel rollout of new key components on the range of products of the firm.

Marsh and Stock established a model of "Intertemporal Integration" that addresses this multiproduct issue [START_REF] Marsh | Building Dynamic Capabilities in New Product Development through Intertemporal Integration[END_REF][START_REF] Marsh | Creating Dynamic Capability: The Role of Intertemporal Integration, Knowledge Retention, and Interpretation[END_REF]. By modelling the product learning cycle, their work aimed at identifying key mechanisms of dynamic capabilities at the interplay between development activities and knowledge activities. This framework remains at an emergent phase and still lacks of empirical insights for the moment.

Brady and Davis [START_REF] Brady | Building Project Capabilities: From Exploratory to Exploitative Learning[END_REF] proposed a model of "Project Capability-Building" which occurs when a firm moves into a new technology and/or market base. The model considers a dynamic sequence a bottom-up project-led learning process with a top-down business-led learning process which fully refines, exploits and expands the firm's organizational capabilities and routines for a better execution performance. This approach particularly addresses the important question of dedicating "vanguard projects" to breakthrough innovations that can be incorporated in the firm's patterns in a dynamic exploration to exploitation process.

THEORETICAL FRAMEWORK AND METHODOLOGY

Research questions

The existing literature reveals a large range of different patterns for product and feature/technology projects interplays. Thus, we are exploring the following research questions:

-To what extent can different types of innovative features be matured in pre-development phases in order to secure product development project? -In the interplay, how to manage the trade-off between the short-term focus of the development project and long-term focus of the innovative feature lifecycle?-What is the result for the innovation strategy performance?

The overall approach of the research is to compare innovation cases by characterizing the product/innovation interplay, the organizational processes and the resulting performance.

Innovation sample

We define an innovative feature as a technical solution providing a new functionality which is not included in any existing products of the brand.

We selected four innovation domains that cover a large diversity of features and address different learning domains, from end-user acceptability of the new feature to technological maturation or disruptive business model exploration: Safety and Driving Assistance systems; Comfort and Convenience; Infotainment and Telematic Services; Powertrain Efficiency and low emissions.

Framing the product/feature interplay with the concept of Innovation Life-Cycle

Management (ILCM)

The key analytical concept of our research is the Innovation Life-Cycle (ILC) or what we called Innovation Route in our preliminary studies [START_REF] Maniak | Shifting from co-development to co-innovation[END_REF]. We define this concept as the set of investigations aimed at exploring different innovative features, preparing them for the application to specific contexts, and capitalizing the related knowledge within the core product-process organization.

We distinguish four types of phases in the ILC. The exploration phase consists in exploring and preparing an innovative feature for upcoming development projects. The contextualization phase consists in preparing a specific proposal to adapt the feature to a vehicle pre-project. The development phase consists in developing the feature within the vehicle development process.

Once the first feature has been marketed, the deployment phase consists in capitalizing on this first experience to rollout the feature on a coherent range of products.

Insert Figure 3 here We use this framework to analyse empirical data following a cross-cases methodology.

We use 5 dimensions to highlight differences in the ILCM of several companies:

The learning dynamic-What are the explored dimensions through the process? What is the level of anticipation before product development on customer benefit as on technology maturation? Decision process-Is there a formalized stage gate process for ILCM? Is it bottom up or top down oriented? Who is involved in those decision processes and what are the risks taken along the feature's Life-Cycle?

Working team on innovation-Is there an official team in charge of managing the innovation life cycle? Is it heavyweight or lightweight? What are its main competences scope and continuity through multi-product deployment of the innovative feature?

Innovation life-cycle institutionalisation within the carmaker's organization-How is the innovation processes connected to product development and functional divisions? What is the business model of the innovative feature within the company?

Cooperation processes with suppliers-How and when do the carmaker involve the suppliers in the ILC? How do the firms share cost, risks and benefits?

Estimating the innovation management performance

In order to evaluate the performance of an ILC, we adopted a four-criterion-ranking, based on: Customer Value-How significant is the benefit brought by the Innovative Feature to the end-user?

Integrability-How easily can the innovative feature be applied to different types of vehicles? Maturity-How reliable and effective is the technology used to make the innovative feature? Profitability-To which extent does the OEM can make a profit out of the innovative feature? Specific scales to track the evolution of these trackers are developed, by separating two different characteristics attached to each of these trackers: its expected level, but also its uncertainty level.

Research team, data collection and progression

The research is organized as an international research collaboration, associating European (CRG, Ecole Polytechnique), Japanese (MMRC, University of Tokyo) and American (IMVP, MIT and Wharton) research teams who aim at understanding the challenges facing the global automotive industry.

The teams have involved three OEMs from Europe and Japan since 2006, giving the opportunity to study seven innovative features lifecycles. We expect the final results will come out in 2009, after the involvement of six other OEMs from Asia, Europe and USA.

3) INNOVATION LIFE-CYCLE MANAGEMENT: 5 CASE STUDIES

This paper draws on five cases studied from 2006 to 2008. We selected the cases to be representative of significantly innovative features, to illustrate quite different types of innovations and exemplify the research questions above. The first two cases show how two different OEMs (one from Asia, one from Europe) did manage the Lifecycle of a similar feature, called ACCESS in this paper. We studied three different feature lifecycles within the same vehicle project of another European OEM, through a typical vanguard strategy.

We had access to key managers and to in-house documentation of the car manufacturers and tier-1 suppliers that were involved in the ILC process. We conducted a total of 42 interviews (an average of 6 interviews for each case study) of diverse manager's profiles (covering project, research, purchasing, technical and so on). We discussed the progresses and results in the research committee gathering the research team and VPs from OEM and Suppliers.

ACCESS lifecycle at OEM_A & OEM B

ACCESS Lifecycle at OEM_A

Exploration. OEM_A is an European OEM. During the 1980s, Exterior Equipment Department and its supplier's counterparts lived a period of changes shifting from mechanical key controlled locks to electric radio-controlled centralized locking systems. But such interest for more advanced automatic opening system decreased in the beginning of the 1990s. From 1992 to 1994 the Research Department launched a research project which led to the first draft of the ACCESS system.

Contextualisation. In mid-1996, a vehicle project called for significant innovative features for product differentiation. The vehicle project leader quickly identified ACCESS feature as a high customer value feature and thus proposed to the Board a version of ACCESS Feature, mixing the in-house system and supplier system. The project asked for important functional enhancement compared to the previously studied solution. Important technological changes were introduced to meet these new requirements. Engineering departments were reluctant, due to the important risks, but the supplier accepted the challenge. In December 1997, the Board decided that ACCESS Feature should be applied to the vehicle. At that time, the vehicle was close the design freeze milestone.

Development. An "Innovation Project Manager" was dedicated to coordinate the development teams and suppliers impacted by the system. The ACCESS project involved numerous surprises caused by unexpected interferences between the vehicles and the ACCESS Innovative Features.

Customer un-anticipated miss-uses of the new feature generated problems during the commercial launching. The system was finally right on-time, even if it caused some quality problems to OEM_A.

Deployment. But this first version of ACCESS was not deployed on other vehicle: the technical problems that emerged during this first application led to come back to technological options that were proposed by the suppliers on the first vehicle, but were too costly. Today, this ACCESS system is deployed on 8 models from 3 platforms. ACCESS is now under the responsibility of a joint electronic -mechanic team, which has been recently co-located.

ACCESS Lifecycle at OEM_B

Exploration -OEM_B is a Asian OEM. In the early 1980s, the Mechanical Division wondered how it could benefit from the generalization of electric power in cars. It launched a two-year study focus on the electrification of the steering column lock. At the same time, the Exterior Equipment Division triggered a parallel study aimed at developing automatic door locking. Both studies failed to show enough benefit to justify more resources, even though the auto-lock project was sold as optional equipment in a luxury car.

Contextualization -The topic was 'silent' until 1995, when the Board voted a customer value based strategy, applying innovative features to upcoming vehicles. The dedicated steering committee nominated a taskforce responsible for introducing the ACCESS feature in the market.

The members of this taskforce were the former pilots of the above cases. They rapidly merged their experience to propose a coherent ACCESS system. They initially targeted the directly upcoming car project, which was a luxury one. After 6 months of study, they realized that no solution could match the cost and functional expectations. Taking advantage from this new trial, they targeted another upcoming vehicle project and managed to build a scenario that met the cost (scale effect), technical functional requirements.

Development -The early collaboration engaged among the different technical departments was identified as a key success factor for the implementation of the feature: technical departments realized that this feature forced the management of new interactions between components, as well as adapting the validation procedures within the vehicle development project. Finally, OEM_B launched the new vehicle on time, and widely based the marketing plan on the promotion of the ACCESS system. The car sales and ACCESS equipment rate were high in comparison with company's standards.

Deployment -Then, OEM_B decided to rollout the feature on other vehicle platforms. The same team supported its roll out to more than a dozen of different vehicles in 5 years time. In order to enhance the customer value on each vehicle, they developed refined versions of the feature to fit to each market segment. Meanwhile, the enlarged knowledge about this feature permitted sourcing of different components of the system from a broader panel of suppliers, which dramatically decreased the cost of ACCESS from one vehicle project to another.

Three Innovative Features at OEM C

OEM_C, a European OEM, marketed at the end of 2006 an innovative car, called InnovCar in this article. This vehicle is for OEM_C a strategic product, realizing 5% of total company sales. It is part of the Multi Purpose Vehicle (MPV) segment. In order to increase its market share on this highly competitive segment, OEM_C realized it had no choice but to innovate. The project team tried to implement a total of 83 innovative features, out of which 48 were finally marketed, typically 2 to 3 times more than other OEM_C vehicles.

Three major innovative features were studied. Two were successfully implemented: the WINDSCREEN and the SEATS. The third one, called TRUNK, was abandoned during the development phase.

WINDSCREEN lifecycle at OEM C

Exploration -The windscreen is an important feature that contributes to key vehicle attributes (cruising ambiance, style and structure). Thus, automotive glass has been an intense domain of innovation since the early 1990's (athermic glass, complexity increase of the shape), especially at OEM_C. In 2000, OEM_C initiated with a supplier a research programme for a completely new type of windscreens: very large windscreens (40% bigger than the biggest existing ones) and highly curved windscreens. At that time, no production process was available at any supplier to produce such windscreens, and it was identified that the only alternative would be to make a technological leap.

The first step was focused on preparing a concept-car, prefiguring a future vehicle, called Vehicle A in this article, to be marketed a couple of years later. This concept-car was seen as an occasion of collective learning between the supplier and OEM_C.

Contextualization -The second step was Vehicle A development, which adopted a very complex shape (derived from, but simpler than the one of the concept car) for the windscreen. OEM_C thus applied the knowledge created with the supplier during the 2000-2002 period. The marketed vehicle benefited from this complex windscreen, but end-users did not consider it as valuable because at that time, the exterior design had not taken advantage of all possibilities of innovative windscreens.

At the beginning of 2003, the project managers of InnovCar adopted the innovative windscreen, which would give it 2-3 years advantage relative to competitors. It selected the same supplier that worked during the previous phases.

Development -This third step was an important and risky challenge for InnovCar managers: no one could evaluate the end-users value for the feature at the beginning of the process; the feasibility of such windscreen, and its integrity in vehicle architecture was still very unsure and there was no possible backup development scenario for the car if the innovation development failed. Nevertheless, InnovCar project manager accepted the challenge and secured the project by adopting specific design processes: 9 months frontload from initial go-no go milestone on the vehicle project; agenda for the exterior design of the car to fit the constraints of the innovative feature; supplier selection process to maximize knowledge capitalization from previous experiences. Such development process allowed the feature to be ready and reliable at the commercial launch of the vehicle.

Deployment -After these successes, OEM C's strategy was to deploy this innovative windscreens lineage through its new vehicles.

Modular SEATS life cycle at OEM C

Exploration and Contextualisation -One other strategic feature for a MPV is its "modularity": end-users not only look for a vehicle able to offer 5 to 7 seats, but they also want the vehicle to store for a lot of luggage in case few people are in the car. At the beginning of the 1990's, an OEM_C competitor introduced rear seats removable from the car. This Innovative Feature gave this OEM a real competitive advantage, and became later a standard of the MPV segment.

Nevertheless the trouble with this feature was the difficulty of removing the seats (comfortable seats tend to be heavy) and of storing them. InnovCar SEATS are innovative because they can fit into the vehicle floor. It is thus easy for the end-user to change the interior configuration of the car.

Surprisingly, the flexible seat idea came late, during the development phase. One could have foreseen that this type of innovation could have been anticipated. Actually, such a feature is so contingent to car body and components that off the shelf exploration is very difficult to justify, as application to a specific vehicle will need major and costly rework.

The SEATS idea emerged from one supplier through a Request for Information process, and was selected by the project team as a key differentiating advantage.

Development -So, even if the seats development process should have been considered

completely out of time on this project, the project leader decided that the vehicle development scheme would have to adapt to the specific needs of these seats. It was decided, in 2003 (less than 3 years before the official commercial launch) that part of the chassis would be redesigned, and the spare wheel would be removed, to provide more room into the vehicle floor.

Actually, this impacted on the whole vehicle and required investment. But the decisions were made in less than 3 months. Moreover, the selected supplier for these seats was not part of OEM_C traditional panel of suppliers before InnovCar project. This risk was hedged by creating different levels of communication between OEM_C and the supplier, for quick problem-solving loops.

After this vehicle development, the seats met a commercial success. Because of the very short time to develop the feature, some minor quality problems had to be managed, but these had been anticipated by the OEM which appointment specific task-force. Development -Two concepts emerged after this creativity phase: one was, unsurprisingly, the shutters concept; the other, called "baggage hold", was much simpler, but partially unsatisfactory.

Deployment

The project manager decided to quickly prototype the two concepts on an existing vehicle, similar to InnovCar. A focus group was set up. For both features, the results of the focus group were disappointing. The end-users were interested by the feature, but seemed not to be ready to pay for it. This was problematic for InnovCar, because both features implied incremental costs, and increased the vehicle weight. Consequently, the project manager decided to give up the development of the innovative trunk.

After this failed application of the feature, the research department decided to continue to work on their primary solution. After 2 years of refinement, they tried once more to "sell" it to a new vehicle development team. The vehicle project manager refused to apply the innovative feature, roughly for the same reasons.

4) FINDINGS FROM THE CASES

The ILCM framework highlights dramatic differences between innovation practices of different companies. We discuss here several findings of this first panel of five features. We expect to validate these hypotheses through the rollout of this methodology on a larger panel in the coming year.

Innovation as an interplay

In the context of automotive industry, the cases confirm that, innovation management does not consist in a linear process which begins with "research" and ends with "development", but in an interplay between product development projects and knowledge activities (from early preparation to standardized application on vehicles). This interplay brings richness as well as complexity in the process. Development projects stand as learning fields for innovative features, because it is possible for the teams working on them to get a deeper access to questions related to the end-user value or the business model of such feature.

Therefore, our analytical model gives a framework to track the activities that a company has to perform in order to transform an idea into a commercial innovative feature applied on a full range of products. This framework can be then fruitful to understand and compare different company strategies.

Limits of off-the-shelf metaphor and the key role of vanguard projects in ILCM

In a context of increasing pressure on vehicle development projects, one could imagine that only off-the-shelf innovative features would have a chance to go to the market successfully. Instead, the cases studied at OEM_C illustrate another pattern. InnovCar project proved to play a key role in selecting and maturing innovative features. Such a result emphasizes the importance of contextualization phase in ILCM. It also shows the importance of learning and adaptability capabilities within the vehicle development process to find out new compromises given the unavoidable surprises of the contextualization phase. This result contradicts the on going trend in auto industry that promotes a real routinization of product development phase, asking for complete upfront validation of any innovative feature. OEM C, as the famous Prius by Toyota [START_REF] Morgan | The Toyota Product Development System[END_REF], illustrate the importance of "vanguard projects" [START_REF] Brady | Building Project Capabilities: From Exploratory to Exploitative Learning[END_REF] even in such stable dominant design context.

The European and Asian Innovation Life Cycle Management

ILCM analytical framework reveals two highly contrasted approaches, in term of performance and process.

The European manufacturer, OEM_A, arrived on the market at an opportune moment, with a clearly targeted feature. However, it suffered from a quality crisis because of poor anticipation and discontinuity in the study on technical maturity and integrity of the feature within a vehicle context.

In contrast, the Asian OEM_B was very efficient to mature the technical solutions, to integrate them within the vehicles, but rather bad performing to define an accurate functional target, and a good business model to launch profitable innovations. Such a result leads to the conclusion that innovation process performance cannot be reduced to technical learning performance through the traditional indicators of quality, cost and lead-time.

This result calls for an articulation between the engineering capabilities, the customer and profit capabilities.

Table 1 shows how such contrasted performances mirror deep differences in life cycle management processes, as analyzed through the five organizational dimensions.

Insert Table 1 about here

Towards a comparison of Innovation Strategies

Such differences between innovation capabilities and innovation/product projects interplay management lead to formalize two different global patterns for innovation strategy of the firm.

On one side, a product-project oriented strategy gives priority to innovations that prove their financial value from the product project perspective, with short-term customer value as a key go/no-go driver for the selection process. In this strategy, the firm manages the innovative feature portfolio through the needs of product project portfolio.

On the other, a strategic view with a more global and long-term perspectives emphasizes brand values and/or technology policies. In this pattern, product project portfolio has to integrate the constraints of the strategic innovations learning tracks.

Our cases explore a variety of situations on this matter (see Table 2). OEM A has a strong product-project oriented strategy while OEM B adopts a clear technology orientation. OEM C appears with a balanced strategy: SEATS and TRUNK cases demonstrate the driving forces of vehicle projects to shape innovation portfolio management. However, WINDSCREEN life cycle reveals how the brand can develop key differentiating innovative attributes through successive vehicle projects. In addition, the unsuccessful TRUNK story shows how upfront technical divisions can maintain their innovation learning tracks beyond vehicle project refusals to market their solutions.

Insert Table 2 about here

CONCLUSION & FURTHER RESEARCH

This paper questioned and enlarged the platform development and technology integration paradigms in projectified firms. Within the context of stabilized product lines, we considered the innovation challenge as the interplay between product / platform projects and innovative features.

We developed a conceptual framework, based on the concept of Innovation Life Cycle Management, in order to compare the evolution of features from their early emergence to their cross-products deployment. This framework characterizes both the process leading the innovation life cycle and the performance related to this process.

Schedule of Figures and Tables

  -Even before the commercial launch of InnovCar, OEM_C decided to apply a similar feature on other vehicles. TRUNK Lifecycle at OEM C Exploration -The last innovation case is related to the trunk of the InnovCar. It proposed a radically new way to open it. Because of the large vertical dimension of an MPV trunk, traditional opening solutions are problematic when there is little room left behind the parked car. Based on this consideration, OEM_C has developed since 2000 a research program focused on innovative concepts for trunks. One concept (called "Shutters" in this article) emerged during this work, which could potentially solve the cluttering problem. Prototypes were made on existing cars (but not on MPV vehicle), in order to test the technical feasibility of the feature. Contextualisation -Not surprisingly, when the Shutter feature was proposed for InnovCar the InnovCar team were not convinced by this upfront solution so they decided to rethink the innovative trunk from scratch. The vehicle development team decided to open up a period for creativity and looked for innovative concepts that would solve this problem of trunk cluttering. During 2 months, an intense work was done within the vehicle development team to find out innovative concepts to realize a very compact trunk opening system.

Figure

  Figure 1: number of vehicle launched by Renault

1 :Figure 2 :Figure 3 : 1 :Figure 1 :

 12311 Figure 1: number of vehicle launched by Renault

We presented an outlook of the application of this framework on five features introduced on various independent platform projects and firms. The results confirm the importance of interplay between product project portfolio management and innovation life cycle management. The study reveals significant differences both in the way firms manage this interplay and the results they achieve in terms of time to market as customer value. The next phase of the research is to deploy a questionnaire-based approach for a systematic comparison of different ILCM practices and performance in the automotive industry.