Fine Detection Of QTLs For Resistance To White Rot Of Vitis Amurensis Rupr. And Analysis Of Disease Resistant Genes Expression

The grape is a perennial vine fruit tree of the family Vitaceae and Vitis.It has a long history of cultivation.The harm of pathogens to grapes is an important factor restricting grape production.Among them,grape white rot(Coniothyrium diplodiella(Speg.)Sace.)is one of the most serious diseases.The cultivated grape varieties in production have a low resistance to white rot.At present,it is mainly controlled by using chemical agents,which not only easily causes pesticide residues,pollutes the environment,but also causes resistance to pathogenic bacteria.Therefore,breeding resistant varieties is a safe,economic and effective way to solve the white rot of grapes.In this research,use two populations and their hybrid genotypes as materials.Two populations are ‘Red Globe’ × ‘Shuangyou’ and ‘Chardonnay’ × ‘Beibinghong’.We collect the leaves and stab them with five needles in vitro at laboratory and use the high-density genetic linkage map to detect fine QTLs about resistance of grape white rot.Then use the bioinformatics analyze detected QTL in the corresponding physical position of the linkage map,screen out candidate genes for resistance of grape white rot,and analyze genes for disease resistance by real-time PCR.The results of this study are as follows:(1)Test populations resistance identification and genetic analysis results: RS and CB populations were identified for disease resistance by indoor in vitro leaves inoculation method to and obtain phenotypic datas.At the first combination,in 2017 and 2018,the disease index of the female ‘Red Globle’ was 50.79 and 64.72,and the disease index of the male ‘Shuangyou’ was 33.3 and 27.78.At another combination,the female ‘Chardonnay’disease index was 51.90 and 51.22 and the male ‘Beibinghong’ disease index was 25.19 and 25.00 in 2017 and 2018,respectively,the phenotypic data of the two combinations showing typical quantitative traits genetic characteristics,showing continuous variation,in two groups.We found a certain proportion of ultra-low parental strains that have a great potential at resistance of grape white rot breeding.(2)Resistant QTL mapping results: Based on the constructed high-density genetic linkage map,combined with the phenotypic datas obtained from the resistance identification,using the interval mapping method(IM)and the composite interval mapping method(CIM)detect resistant QTLs for RS and CB populations.at the RS population,we found four resistant QTLs,which were distributed in LG1,LG7,LG10 and LG18.In the CB populations,four resistant QTLs were finally obtained,which were distributed in LG4,LG7,LG11,and LG13.(3)Screening of candidate resistant genes and real-time PCR results: After analyzing the localization results,8 resistant QTL loci were finally obtained,and their positions on the genetic map were determined by the markers linked to them,and screen out the candidate genes related to white rot resistance at database CRIBI.Finally,three genes showing that are related to resistance of white rot at grape,which were PR gene,RPM1 gene and NB-ARC gene.The relative expression of PR gene,RPM1 gene and NB-ARC gene in the resistant varieties ‘Shuangyou’ and ‘Beibinghong’,was higher than that of susceptible varieties ‘Red Globe’ and ‘Chardonnay’.It is indicated that the PR gene,RPM1 gene and NB-ARC gene have effective resistance for grape white rot.