Pooled sequencing reveals genome regions involved in resistance to bacterial wilt in Italian ryegrass

Abstract

Xanthomonas translucens pv . graminis (Xtg) is the causal agent of bacterial wilt, one of the main diseases of Italian ryegrass (Lolium multiflorum Lam .) . One major QTL for resistance was previously discovered, but the underlying genes are yet to be determined. In order to fine-map this QTL, a mapping population consisting of 7,484 F2 individuals segregating for resistance was established in the greenhouse and inoculated with a highly virulent Xtg strain . Two pools of the most resistant and the most susceptible individuals were sequenced and SNPs associated with resistance were identified. Most of the significant SNPs map to linkage group 4, where the QTL was previously identified. Genes containing these SNPs will be determined and will constitute candidate resistance genes to be investigated further .

High‐resolution bulked segregant analysis enables candidate gene identification for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.)

“…It also demonstrates the efficacy of BSA based on whole genome sequencing of pools of contrasting phenotypes to identify candidate genes associated with a binary trait of interest in a L. multiflorum biparental F 2 population. While previous work based on a first draft of the M2289 genome assembly was able to identify genomic regions associated with resistance mapping to chromosome 4, the very fragmented nature of this genome assembly, as well as the lack of reliable information on the position of each scaffold on chromosomes, did not allow for a precise location of the resistance gene in the genome (Goettelmann et al, 2021;. The recent development of a high-quality chromosome-level genome assembly of Rabiosa allowed to produce the updated chromosome-level genome assembly M2289_v2.…”

High-resolution bulked segregant analysis enables candidate gene identification for bacterial wilt resistance in Italian ryegrass

“…While previous work based on a first draft of the M2289 genome sequence was able to identify genomic regions associated with resistance mapping to chromosome 4, the very fragmented nature of this genome assembly, as well as the lack of reliable information on the position of each scaffold on chromosomes, did not allow for a precise location of the resistance gene in the genome (Knorst et al, 2018a; Goettelmann et al, 2021). The recent development of a high-quality chromosome-level genome sequence of Rabiosa allowed to produce the updated chromosome-level genome sequence M2289_v2.…”