| Gray mold is a fungal disease.There are gray mold damages in many viticulture areas in China.The occurrence of diseases has caused economic losses to grape production.At present,the most common control method is chemical agent treatment,which not only increases the cost of production,but also causes harm to human body and pollution to the environment after long-term use.The most fundamental way to solve this problem is to cultivate high-quality and high-resistance grape varieties.In this study,31 grape cultivars,‘Red Globe'בVenus Seedless' hybrid progeny population and ‘Zhuosexiang'בVictoria' hybrid progeny population are used as the experimental materials for identification and analysis of gray mold resistance,screening high resistance germplasm resources against gray mold,combined with high-density genetic map to locate the QTL for resistance to gray mold,the expression response of the candidate gene was analyzed and its expression response to gray mold was verified,to provide a reference for the cultivation of high quality and high resistance grape cultivars.The main results are as follows:1.The resistance of 31 grape cultivars to gray mold was identified,and the results showed that several varieties with high resistance to gray mold are ‘Zuoyouhong',‘Gongzhubai',‘Concord',‘Shuangyou' and ‘Beibinghong',and several varieties with poor resistance,for ‘Centennial Seedless',‘Rizamat' and ‘Italia'.Through comparison,it was found that the V.labrusca L.,V.amurensi Rupr.and V.vinifera L.×V.amurensi Rupr.had higher resistance to gray mold,while the V.vinifera L.was generally susceptible.The microstructure of 5 cultivars with different resistance to gray mold was observed,including ‘Concord',‘Venus Seedless',‘Cabernet Sauvignon',‘Red Globe' and ‘Centennial Seedless'.It was found that the growth of Botrytis cinerea in ‘Concord' and ‘Venus Seedless' leaves was inhibited,and the morphology of mycelium changed significantly.While ‘Cabernet Sauvignon',‘Red Globe' and ‘Centennial Seedless' had no obvious inhibition on Botrytis cinerea,the morphology of mycelium did not change.The disease resistance of the ‘Red Globe'בVenus Seedless' hybrid progeny population and the ‘Zhuosexiang'בVictoria' hybrid progeny population were identified,and it was found that the hybridization progeny of the two populations significantly separated the resistance to gray mold,which showed continuous distribution,genetic characteristics of quantitative traits,and a certain proportion of transgressive advantage appeared,which provided the basis for breeding high quality and high resistance cultivars.2.The genetic map of grape was constructed with ‘Red Globe'בVenus Seedless' and its 176 offspring,and the QTL mapping of gray mold resistance was carried out by combining the two-year gray mold resistance identification phenotype data.On the integrated map of ‘Red Globe'בVenus Seedless',a total of 6 QTL loci were mapped,which were distributed on the LG1,LG3,LG6,LG7 and LG11 linkage groups.The contribution rate of these loci when present alone was 10.3%-19.6%.3.According to the QTL locus mapping in the ‘Red Globe'בVenus Seedless' population,analyzed relevant resistance genes,6 related resistance candidate genes were selected: TIR1,TIR2,DIS3,DIS4,SER5 and PAT7.Real-time fluorescence quantitative analysis of the relative expression of these 6 genes in different stages of the susceptible cultivars ‘Red Globe' and ‘Victoria',resistant cultivars ‘Venus Seedless' and ‘Zhuosexiang' inoculated with gray mold,the results showed that the same genes in different cultivars and different periods is obvious different.It is speculated that TIR1,TIR2 and DIS3 genes may play an important role in inhibiting Botrytis cinerea in disease-resistant cultivars. |
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