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Existence of qualitative resistance against blackleg disease in Brassica oleracea L. and detection of gene-specific single nucleotide polymorphism
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/302889
Blackleg disease caused by Leptosphaeria maculans, is the most devastating disease of Brassica germplam worldwide that causes million tonnes of crop losses per year throughout the world. To date, a total of 12 race-specific resistance genes of Brassica napus to L. maculans have been reported but linkage mapping analysis reveals that all of those loci are located in A genome i.e., in B. rapa chromosomes. B. oleracea has high ancestral synteny with B. rapa through their evolution. We believe that presence of qualitative resistance is possible in B. oleracea germplasm. The present study was therefore planned to find out any race-specific qualitative resistance gene present in C genome of B. oleracea. A total of 16 microsatellite markers were used which are linked to seven different Rlm and Lep genes of B. napus to screen 32 inbred lines of cabbage. Primers were designed based on homology assessment in corresponding nucleotide sequence available in Bolbase (a B. oleracea genome database, http://www.ocri-genomics.org/bolbase/index.html), located in B. oleracea scaffolds/chromosomes. Out of 16 SSR markers, 13 were found polymorphic which indicates possible existence of resistant genes in cabbage lines. The inbred lines are then assessed against two L. maculans stains with known avirulent genes. Some inbred lines were hypersensitive against gene-specific virulent strains of L. maculans that confirmed existence of Rlm1, Rlm2, Rlm4, LepR3 and LepR4 in the cabbage lines. In this way we were able to select out resistant and susceptible lines against each resistant gene. The gene-specific polymorphic SSR marker regions were cloned and sequenced and candidate SNPs were identified for confirmation of their functionality.
