Evaluating Of Drought Tolerance Of Five Grape Rootstock Varieties And Function Study Of LEA11 Gene In Grape

As one of the most important kinds of abiotic stress,drought seriously restricted the development of grape industry.Screening and utilizing high drought-tolerance grape rootstocks,and studying the drought-tolerance gene have important application value and theoretical value for grape drought resistance.In this study,5 kinds of grape rootstock were treated under drought stress,by using different water gradients.And,1 kind of rootstock was selected by comprehensive systematic evaluation.Based on the grape genome,through annotating grape LEA gene family and analyzing eene differential expression under osmotic stress,a severest responsive gene was selected as the target gene.Based on these research,we cloned the target gene and stably transformed it into’41B9 suspension cells and studied the function of the target gene.The results are as follows:1.A kind of rootstock,’llOR5,has the highest drought tolerance capacity among 5 rootstocks.Its comprehensive evaluation value(D value)of drought tolerance was 0.871,the highest.We used principal component analysis,membership function analysis and cluster analysis to evaluate the ability of drought tolerance.Besides,combined with gray correlation analysis,we obtained the indicators which were closely related to drought tolerance.They were antioxidant enzyme activity,leaf photosynthetic index,membranous peroxidation level,and biomass.These indicators could be used as primary factors for evaluating drought-tolerance on grapes.2.52 LEA genes were identified from the grape genome by Hidden Markov Model and BLAST and Conservative Domain Analysis.According to the transcriptome data under osmotic stress,52 LEA genes were differentially expressed,and 23 genes with up-regulated expression were obtained.The relative expression of LEA1H gene was increased by 700 times at 24 h after osmotic stress.The response to osmotic stress was the most severe.3.The grape gene LEA1H was cloned in ’110R’,and its full length was 393 bp,encoding 130 amino acids.The subcellular localization results showed that LEA11 was colocalized.4.The rootstock ’41B’ suspension cells were infected by Agrobacterium and the callus material stably overexpressing LEA11 gene was obtained by screening,and seedlings were induced.By measuring the electrical conductivity of LEA11 gene overexpression(OE)and stable transformation of empty-vector(EV)callus materials,SOD,POD and other related physiological indicators,it was found that compared with EV,the conductivity of OE was significantly decreased,SOD activity and POD activity significantly increased.So,under these preliminary studies,LEA11 gene was considered closely related to drought-tolerance.