| Grapevine is one of the most important fruit trees and it was widely cultivated all over the world for its outstanding economic and social value.Grape white rot disease caused by Coniothyrium diplodiella(Speg.)Sacc.seriously affected the grape yield and quality.Until now,only a few related researches were reported but the internal mechanism of grape white rot resistance was still limited.An alternative strategy is cultivating white rot resistance cultivar through traditional crossbreeding.While traditional crossbreeding was lengthy,costly and had lower breeding efficiency in the past.In recent years,as the development of molecular biological technique as well as the completion of grape whole genome sequencing,marker-assisted selection(MAS)based ong these works can make breeding more efficient and precise.It has been widely used for the research of grape important agronomic traits breeding.So,the resistance related genes discovery and molecular development based on transcriptome analysis and QTL mapping possess important theoretical and practical significance for grape white rot resistance breeding in the future.In this study,grape cultivar “Zhuosexiang”(V.vinifera L.× V.labrusca L.)and “Victoria”(V.vinifera L.)which showed significant difference in white rot resistance were selected as the plant material,transcriptome analysis was conducted for white rot infected leaves,these two cultivars were also used for the hybrid population construction and white rot resistance QTL mapping.The main results are as follows:1.The grape cultivar “Zhuosexiang” was used as the female parent and “Victoria” used as the male parent,after interspecific hybridization,in total of 672 individuals were harvested.Among these hybrid offspring,177 seedlings and the two parents were used as the white rot resistance identification and genetic analysis.Based on 4 replicated experiments of white rot resistance identificated in 2017 and 2018,the white rot resistance of hybrid offspring showed continuous variation,which is a typical quantitative trait controlled by multiple genes.According to the broad sense heritability analysis,white rot resistance of this hybrid population was major controlled by genetic factor and some indivals which showed high white rot resistance were selected;2.Illumina and SMRT sequencing were conducted for white rot infected leaves of these two grape cultivars after 0 h and 72 h,in total of 18,698 gene loci and 37,010 unique full-length isoforms were achieved,including 3999 new loci and 27,560 new isoforms.A new transcript library containing 53,906 transcripts was constructed after the combination of novel transcripts identified by SMRT sequencing and annotated transcripts from the reference genome.3.The differentially expressed genes(DEGs)analysis during different cultivars and different infection period was conducted bsed on Illumina sequencing and our new constructed library.The result showed that,grape PR1(pathogenesis-related protein 1)which mediated by salicylic acid(SA)and jasmonic acid(JA)signaling pathway may played crutial role in white rot resistance,furthermore,genes involved in SA and JA signaling pathway showed different expression in these two cultivars,this may be the reason of different white rot resistance level;4.A high-density genetic linkage map was constructed based on RAD-seq,containing 6249 molecular markers and the average genetic distance of adjacent markers was 0.50 c M.Based on the linkage map and white rot resistance identification in two years,we conducted the white rot resistance QTLmaping.In total of 4 stable QTLs were discovered on LG14,the explained phenotypic variation of them were ranged from 12.93% to 13.43%.A molecular marker which co-segregated with grape white rot resistance was discovered based on QTL maping result.Combined with the different expression data of RNA-seq,two candidate ?R? genes which may play important role in grape white rot resistance were selected. |
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