QTL Mapping And Candidate Gene Research Of Grapevine Botrytis Cinerea Resistance

In this study,the hybrids of ‘Red Globe' × ‘Shuangyou' and ‘Chardonnay' × ‘Beibinghong' are used as test materials to identify their resistance in the method of inoculation of mycelium in vitro.Combining the established genetic linkage maps of grapes and the resistance phenotypic values,to locate the resistant QTLs of the grape to Botrytis cinerea in the interval mapping method.The genes related to resistance in the positioning segment are found out and t the 3 candidate genes SGT1,MYB44 and ERF023 are screened out.The resistant cultivar ‘Zhuosexiang' and the susceptible cultivar ‘Victoria' are used as tested materials,The expression levels of three andidates genes,SGT1,MYB44 and ERF023 at different times after inoculation with Botrytis cinerea are detected by the real-time fluorescence quantitative PCR.The results are as follows:In the inoculating method of indoor vitro leaves,the resistance to Botrytis cinerea of 149 strains of 'Red Globe' × 'Shuangyou' hybrids and 130 strains of 'Chardonnay' × 'Beibinghong' hybrids are identified.The results show that the absolute values of the kurtosis and skewness of two groups are all less than 1,which indicates that the index of the resistance to Botrytis cinerea of these population satisfies a normal distribution;the disease incidence of individuals in two groups is found to be different significantly,their genetic characteristics distribution is continuous,which is consistent with the regular pattern of quantitative traits inheritance,the resistance phenotypic values can be used for QTL mapping analysis of resistance to Botrytis cinerea.Combined with the existing linkage genetic maps and resistance phenotypic values,the QTL site for resistance to Botrytis cinerea with a LOD ? 3.0 was screened out by MapQTL5.0.In the group 'Red Globe' × 'Shuangyou'.Fifteen QTLs are detected,six QTLs are detected in the interated maps,mainly distributed on the LG2,LG5,LG6,LG15,LG18 and LG19 linkage groups.Four QTLs are detected on the maternal 'Red Globe' maps,distributed on the LG6 and LG18 inkage groups,Five QTLs are detected in the paternal 'Shuangyou' maps;distributed on the LG2,LG5,LG15 and LG19 linkage groups.Ten QTLs are detected in the 'Chardonnay'×'Beibinghong' populations,and four QTLs are detected in the interated maps,mainly distributed on the LG1,LG4,LG14 and LG15 linkage groups;in the paternal 'Beibinghong' maps,Three QTLs are detected on the LG1,LG14 and LG15 linkage groups;two QTLs are detected on the maternal 'Chardonnay' maps;distributed on the LG1 and LG15 linkage groups.Based on the results of QTL mapping for the resistance to Botrytis cinerea,the bioinformatics of the genes are analysised in the QTLs segment,and SGT1,MYB44 and ERF023 are used as candidate genes.The relative expression levels of SGT1,MYB44 and ERF023 candidate genes in the resistant cultivar ‘Zhuosexiang' and the susceptible cultivar ‘Victoria' at different infestation times are analyzed by the real-time fluorescence quantitative PCR.The expression of the three candidate genes in the resistant varietie is higher,and there is different expression in time.This suggests that the three candidate genes of SGT1,MYB44,and ERF023 may play different roles in the varietie and susceptible varietie against Botrytis cinerea.