Cloning and expression analysis of xyloglucan endotransglucosy- lase/hy- drolase （XTH） gene in jujube fruit

Abstract：In order to study the relationship of Xyloglucan endotransglucosylase/hydrolase （XTH） and fruit growth and softening in two jujube （Ziziphus jujuba M.） cultivars, Li jujube and Zhanhua Dong jujube, two partial XTH cDNA sequences were obtained by 3 RACE, and the expression of XTH genes during fruit growth and ripening at the room temperature was investigated by real-time quantitative PCR （RT-qPCR）approach. The results showed that, the two partial XTH cDNA sequences named ZJXTH1 （Gen- Bank accession number： HQ896312） and ZJXTH2 （GenBank accession number： HQ896313） were 776bp, containing 636 bp ORF and coding 212 amino acids. The results of homologous analysis in GenBank demonstrated that the ZJXTH sequences were 68% to 78% identical with those of other plants on the nucleotide sequences and the deduced amino acid sequences. The expression of ZJXTH genes accumulated since 51 days after flowering in both jujube cultivars and was markedly higher during the fruit ripen and storage than the growth period. The ZJXTH1 expression displayed up-down-up trend during the storage, and the maximums appeared in the fruit turning red and rapidly softening period. The ZJXTH2 expression displayed up-down trend during the storage, and the maximum appeared in the fruit turning red period. All these results suggest that the XTH gene might play a promoting role in the jujube fruit ripeness and softening process.