The sorbitol,fructose and glucose contents and the changes in activities of sorbitol oxidase (SOX),sorbitol dehydrogenase (SDH),which are the enzymes participated in sorbitol metabolism,were investigated respectively in the endocarp,mesocarp,leaf and phloem during the development of fruits of ’Jingyu’and ’Okubao’ peach. The results demonstrated that the pattems of sugar accumulation were analogous in the two varieties. In addition,sorbitol content in leaf was the highest in leaf,followed by that in phloem,and then in pericarp. The contents of glucose and fructose had obvious diversity in disparate parts. At the same time,the changes of SDH and SOX activities had same trend in the two varieties,with a big wave in fruit,and relative unchanged over time in leaf and phloem. Moreover,the testing value of every index was close to zero in endocarp around the 60 th day or so after anthesis,which suggested that the basic metabolism was stagnated. However,the sorbitol metabolism in mesocarp increased sharply,which reflected it came into a new development stage.
[Objective] The aim was to clone the CmNAC gene from Cucurbita moschata and analyze the sequence characteristics. [Method] A pair of degenerate primers was designed based on the conserved sequences of NAC gene from Brassica napus, Lycopersicon esculentum and Capsicum annuum. NAC transcription factor gene was amplified by RT-PCR from Cucurbita moschata leaves and cloned into pMD-19T vector; then the recombinant clones were sequenced. Finally, the sequences of nucleic acid and amino acid were analyzed using BLAST and DNAMAN software. [Result] The NAC transcription factor gene cloned from C. moschata included 442 bp encoding 147 amino acids, named CmNAC. The NAC gene fragment contained a conserved region like other plant NAC genes and belonged to the NAC family ATAF1/2 subfamily. [Conclusion] The stress resistance related gene NAC cloned from C. moschata is a foundation for further study on the biological function of the gene and plant genetic engineering.
