Michel Renard

Bio: Michel Renard is an academic researcher from Institut national de la recherche agronomique. The author has contributed to research in topics: Leptosphaeria maculans & Population. The author has an hindex of 39, co-authored 130 publications receiving 5743 citations. Previous affiliations of Michel Renard include University of Rennes.

Early allopolyploid evolution in the post-Neolithic Brassica napus oilseed genome

Abstract: Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.

Identification of the fertility restoration locus, Rfo, in radish, as a member of the pentatricopeptide-repeat protein family

Abstract: Ogura cytoplasmic male sterility (CMS) in radish (Raphanus sativus) is caused by an aberrant mitochondrial gene, Orf138, that prevents the production of functional pollen without affecting female fertility Rfo, a nuclear gene that restores male fertility, alters the expression of Orf138 at the post-transcriptional level The Ogura CMS/Rfo two-component system is a useful model for investigating nuclear-cytoplasmic interactions, as well as the physiological basis of fertility restoration Using a combination of positional cloning and microsynteny analysis of Arabidopsis thaliana and radish, we genetically and physically delimited the Rfo locus to a 15-kb DNA segment Analysis of this segment shows that Rfo is a member of the pentatricopeptide repeat (PPR) family In Arabidopsis, this family contains more than 450 members of unknown function, although most of them are predicted to be targeted to mitochondria and chloroplasts and are thought to have roles in organellar gene expression

Quantitative resistance increases the durability of qualitative resistance to Leptosphaeria maculans in Brassica napus

Abstract: It has frequently been hypothesized that quantitative resistance increases the durability of qualitative (R-gene mediated) resistance but supporting experimental evidence is rare. To test this hypothesis, near-isogenic lines with/without the R-gene Rlm6 introduced into two Brassica napus cultivars differing in quantitative resistance to Leptosphaeria maculans were used in a 5-yr field experiment. Recurrent selection of natural fungal populations was done annually on each of the four plant genotypes, using crop residues from each genotype to inoculate separately the four series of field trials for five consecutive cropping seasons. Severity of phoma stem canker was measured on each genotype and frequencies of avirulence alleles in L. maculans populations were estimated. Recurrent selection of virulent isolates by Rlm6 in a susceptible background rendered the resistance ineffective by the third cropping season. By contrast, the resistance was still effective after 5 yr of selection by the genotype combining this gene with quantitative resistance. No significant variation in the performance of quantitative resistance alone was noted over the course of the experiment. We conclude that quantitative resistance can increase the durability of Rlm6. We recommend combining quantitative resistance with R-gene mediated resistance to enhance disease control and crop production.

Gene flow from transgenic crops

Abstract: Gene flow from crops to related wild species must be considered when assessing the potential environmental impact of cultivating genetically modified plants1. Evidence of pollen dispersal within species has been found for several crops but little information is available on spontaneous gene flow from crops to related species with simultaneous flowering periods2,3. To study the genetic mechanisms involved, we have developed an intergeneric model of gene flow from transgenic oilseed rape (Brassica napus L.; genotype, AACC; diploid chromosome number, 2n=38) containing one copy of the bar gene, which confers resistance to the herbicide Basta (glufosinate ammonium), to wild radish (Raphanus raphanistrum L.; genotype, RrRr; 2n=18), a widely distributed weed.

Method of producing double low restorer lines of Brassica napus having a good agronomic value

Abstract: A method of producing double low restorer line of Brassica napus for Ogura cytoplasmic male sterility (cms) presenting radish introgression carrying the Rfo restorer gene deleted of the radish Pgi-2 allele and recombined with the Pgi-2 gene from Brassica oleracea, and having a good agronomic value characterized by female fertility, a good transmission rate of Rfo and a high vegetative vigour A method of forming Brassica napus hybrid seeds and progeny thereof The seeds of Brassica napus and use of the combined markers PGIol, PGIunt, PGIint, BolJon and CP418 for characterising

Hybridization using cytoplasmic male sterility, cytoplasmic herbicide tolerance, and herbicide tolerance from nuclear genes

Abstract: The process of the present invention provides a convenient route for producing a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination Cytoplasmic male sterile plants which also exhibit cytoplasmic herbicide tolerance (ie, to a Type A herbicide) and tolerance to a different herbicide attributable solely to nuclear genes (ie, to a Type B herbicide) are the key plants for use in the present process The maintainer and restorer plants exhibit tolerance to different herbicides (ie, to either a Type A herbicide or a Type B herbicide) The economical bulk planting of the parent plants is made possible during each step of the process For instance, cytoplasmic male sterile plants, plants resulting from the self-pollination of a maintainer, and restorer plants can be grown in a substantially random population, with the self-pollinated maintainer plants being destroyed by an appropriate herbicide prior to pollination, and the self-pollinated restorer plants being destroyed by an appropriate herbicide immediately following pollination or in the subsequent generation The process of the present invention is applicable to grain crops, forage crops, seed-propagated fruits, seed-propagated ornamentals, and industrial species In a particularly preferred embodiment a predetermined variety of Brassica napus (ie, rape or improved forms thereof known as canola) is formed which is the product of cross-pollination

Pathogen population genetics, evolutionary potential, and durable resistance

Abstract: ▪ Abstract We hypothesize that the evolutionary potential of a pathogen population is reflected in its population genetic structure. Pathogen populations with a high evolutionary potential are more likely to overcome genetic resistance than pathogen populations with a low evolutionary potential. We propose a flexible framework to predict the evolutionary potential of pathogen populations based on analysis of their genetic structure. According to this framework, pathogens that pose the greatest risk of breaking down resistance genes have a mixed reproduction system, a high potential for genotype flow, large effective population sizes, and high mutation rates. The lowest risk pathogens are those with strict asexual reproduction, low potential for gene flow, small effective population sizes, and low mutation rates. We present examples of high-risk and low-risk pathogens. We propose general guidelines for a rational approach to breed durable resistance according to the evolutionary potential of the pathogen.

Early allopolyploid evolution in the post-Neolithic Brassica napus oilseed genome

Abstract: Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.

Phenolics in food and nutraceuticals

Abstract: Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Sequencing of allotetraploid cotton ( Gossypium hirsutum L. acc. TM-1) provides a resource for fiber improvement

Abstract: Upland cotton is a model for polyploid crop domestication and transgenic improvement. Here we sequenced the allotetraploid Gossypium hirsutum L. acc. TM-1 genome by integrating whole-genome shotgun reads, bacterial artificial chromosome (BAC)-end sequences and genotype-by-sequencing genetic maps. We assembled and annotated 32,032 A-subgenome genes and 34,402 D-subgenome genes. Structural rearrangements, gene loss, disrupted genes and sequence divergence were more common in the A subgenome than in the D subgenome, suggesting asymmetric evolution. However, no genome-wide expression dominance was found between the subgenomes. Genomic signatures of selection and domestication are associated with positively selected genes (PSGs) for fiber improvement in the A subgenome and for stress tolerance in the D subgenome. This draft genome sequence provides a resource for engineering superior cotton lines.