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Merdinoglu, D.

Publications and source records attributed to Merdinoglu, D..

7 recordsLinked to original sources

Comparative assessment of genomic, phenomic, and metabolomic prediction models in biparental grapevine breeding populations

Accelerating grapevine breeding for disease resistance and climate adaptation remains constrained by long generation cycles. We benchmarked genomic (SNP), phenomic (NIRS), and metabolomic (untargeted LC-MS) prediction for 24 agronomic traits in a biparental population phenotyped over three years. Seven statistical frameworks and four tissue x timepoint combinations (wood; vineyard leaves at budbreak and flowering; greenhouse leaves at flowering) were evaluated, together with feature-wise BLUPs across samples. Cross-year and cross-population analyses with two additional populations assessed temporal robustness and transferability. Genomic prediction was most accurate (up to r = 0.83), metabolomic prediction was intermediate (up to r = 0.59), and phenomic prediction was lowest (up to r = 0.39) despite its lower acquisition cost. Metabolite features were more heritable than NIR wavelengths, for which most unexplained variation remained residual under the fitted model. Multi-omics integration produced limited overall gains. These results support genomic selection as the primary approach, with metabolomic or phenomic screening considered only for traits and sampling designs that show reproducible predictive signal.

genomics↗

Uncovering the genetic basis of agronomic traits in over 1,000 grapevine genotypes derived from a disease resistance breeding program

Breeding disease-resistant grapevines that retain agronomic performance under variable climates requires loci and predictions that transfer across related hybrid families. We analyzed 1,081 genotypes from 95 crosses within the French INRAE-ResDur breeding program for 13 phenology, yield and berry-composition traits evaluated at five sites from 2006 to 2024. We integrated within-family QTL mapping, kinship- and population-adjusted multiple-population QTL mapping in 772 progeny, and structure-aware GWAS in 899-968 individuals, depending on the trait, together with cross-environment, cross-trait and local genomic estimated breeding-value analyses. Genetic and phenotypic differentiation among families strongly affected locus detection. Of 76 family-QTL intervals, seven, representing six trait-region hypotheses, were locally concordant across all three mapping frameworks. The strongest recurrent evidence involved a chromosome-16 region for veraison and harvest date, where a localGEBV block at 14.69 Mb ranked first for veraison and second for harvest; chromosome-14 cluster traits and chromosome-1 compactness emerged as additional validation priorities. Cross-environment meta-analysis detected no common fixed-effect association at 5% FDR but revealed extensive heterogeneous evidence. Cross-trait analysis grouped 270 significant marker tests into 54 candidate multi-trait regions, without establishing biological pleiotropy. Population-adjusted localGEBV yielded a mean leave-one-population-out correlation of 0.470 between phenotypic BLUPs and genomic scores across traits. These results distinguish compact haplotype-validation targets from background- and environment-dependent signals, supporting a staged strategy that combines marker- assisted selection for validated recurrent regions with externally validated multi-trait, multi- environment genomic prediction for polygenic traits.

genetics↗

Metabolic biomarker-based phenotyping unveils quantitative effects of plant resistance and pathogen aggressiveness in the grapevine (Vitis spp.) - downy mildew (Plasmopara viticola) pathosystem.

Grapevine resistance to downy mildew has been primarily associated with major "Resistance to Plasmopara viticola" (Rpv) loci, which are extensively used in breeding programs. Resistant varieties represent an effective solution to mitigate the environmental impact of fungicide application in viticulture, but P. viticola strains able to overcome major Rpv have become a main threat to their cultivation. Pyramiding resistance loci in the same variety enhances plant resistance, but interactions involving stacked and defeated Rpv and different P. viticola strains are poorly documented. Investigation of these interactions may uncover new information for the development of efficient breeding strategies, the optimal exploitation of Rpv, and the building of durable resistance. In the present study, a grapevine offspring carrying single and pyramided Rpv1, Rpv3.1 and Rpv10 was phenotyped in laboratory conditions for the resistance to P. viticola using a naive strain and a strain virulent towards Rpv10. By using a high-resolution phenotyping strategy based on P. viticola metabolic biomarkers, we demonstrated that the efficacy of Rpv combinations and aggressiveness of P. viticola strains can be quantified in the early phase of infection and were often related to sporulation outcome. Furthermore, we described how a limited residual effect of a defeated Rpv may become significant in pyramiding. In conclusion, in addition to providing the keys to streamlining resistance utilization in grapevine, our research presents a distinctive case study that provides valuables information for breeding new resistant varieties, thanks to an innovative "omic"-based phenotyping approach, which may be adapted to other plant pathosystems.

plant biology↗

Breeding for durable resistance in crops: defeated loci may act as Trojan horses compromising the effectiveness of major resistance genes.

Resistance breeding offers invaluable perspectives for environment-friendly crop protection, but its success may be limited by the breakdown of plant resistance by pathogen strains. This threat is particularly acute for perennial crops, which may be cultivated for several decades. With the increasing use of new varieties carrying multiple major resistance loci, grapevine (Vitis spp.) represents a distinctive model to investigate the broad agreement that combining several resistance genes (pyramiding) enhances both resistance efficacy and durability. To this end, grapevine progenies segregating for four resistance loci against Plasmopara viticola (Rpvs) were used to evaluate the efficiency of single and pyramided major loci when confronted to naive and Rpv-breaking pathogen strains. In the context of polygenic resistance, both undefeated and defeated Rpvs provided significant quantitative effects. However, interactions between pyramided Rpvs were either beneficial, neutral or detrimental to the level of resistance, depending on the loci combination and pathogen strain. In particular, the fact that the presence of defeated resistance loci may compromise the resistance provided by functional major loci has important implications for crops resistance breeding. Thorough phenotypic investigations of pyramiding breeding schemes emerge as a critical step for the effective and durable management of genetic resistances and plant diseases.

plant biology↗

Impact of the introgression of resistance loci on agro-oenological traits in grapevine interspecific hybrids

O_LIA major aim in modern grapevine (Vitis vinifera L.) breeding programs is the introgression of disease resistance genes along with desired cultural and nological traits. Understanding the genetic links between resistance genes and agro-nological traits is a crucial issue for grapevine breeders. C_LIO_LIWe studied the genetic determinism of a wide range of agro-oenological traits in a complex interspecific hybrid population and identified two cases of colocalizations with disease resistance quantitative trait loci (QTL). C_LIO_LIThe species of origin of chromosomal regions in the off-springs were determined thanks to in silico chromosome painting. The linkage drag around resistance genes from primary gene pool was assessed as low due to a good recombination rate with V. vinifera. C_LIO_LIWe established that wild Vitis species are, apart from their interest in disease resistance, essential resources for improving the cultural characteristics of grapevine. C_LI

plant biology↗

Rpv2 is part of a cluster of NLRs specific to Vitis rotundifolia and confers extreme resistance to grapevine downy mildew.

Downy mildew caused by the oomycete Plasmopara viticola is one of the most important diseases affecting grapevine. Resistant varieties are an environmentally-friendly tool to control grapevine downy mildew. Efficient breeding for durable resistance requires knowledge of the underlying mechanisms. Here we aimed at identifying the molecular basis of Rpv2, a gene for extreme resistance to downy mildew derived from Vitis rotundifolia, and at characterizing its effect on pathogen development. Individuals from two populations segregating for Rpv2 were evaluated for resistance to downy mildew and genotyped. Following genetic mapping, markers flanking Rpv2 were used to screen new populations and identify recombinant individuals. Sequencing of recombinants and in silico chromosome painting was used to reduce the interval containing Rpv2. Comparative genomics inside the Vitaceae, involving de novo assembly of the V. rotundifolia Regale genome, allowed narrowing-down the list of candidate genes. We restrict Rpv2 to a 250 kb genomic region that contains two resistance genes of the NLR type. Comparative genomics analyses could not find orthologs of both NLRs in the other Vitis species studied. We also show that Rpv2-mediated resistance leads to pathogen arrest early in the infection cycle. Our results show that Rpv2 belongs to the NLR family of resistance genes, contributing thus to understand the potential and risks of its use in breeding programs and suggesting that combining NLR-type genes may lead to durable resistance KEY MESSAGEThe Rpv2 locus for extreme resistance to grapevine downy mildew is mapped to a 250 kb genomic region containing two NLR-type genes specific to V. rotundifolia.

plant biology↗

Discovery of a locus associated with susceptibility to esca dieback in grapevine

Esca is the most destructive and predominant grapevine trunk diseases. The chronic infections and vine mortality caused by esca syndrome lead to huge economic losses and threatens the sustainability of vineyards worldwide. Although shown as associated with the presence of wood fungi, the etiology of esca remains still unclear and putatively involves multifactorial causes, which makes the development of effective control methods challenging. As differences in esca susceptibility had already been observed among grapevine varieties, we investigated in a biparental population the presence of genetic factors that can explain theses variations. Thanks to the destructive phenotyping of a 16-year-old vineyard plot, we discovered that the Gewurztraminer variety carries on chromosome 1 a locus linked to variations in trunk necrosis associated with esca, which we have named ENS1. Our study also suggests that there is a partial link between trunk vigor and necrosis due to esca. To our best knowledge, ENS1 is the first instance of genetic factor identified as involved in the limitation of necrosis associated to grapevine esca. While the identification of ENS1 alone may not provide a complete resolution of the esca issue, this discovery represents nonetheless a first step towards a genetic solution and paves the way for broader genetic investigations in the future.

genetics↗