摘 要 ：依据火把梨编码谷胱甘肽S-转移酶(GST)的EST序列设计基因特异引物，采用快速扩增cDNA末端技术，从云南火把梨中克隆到一个新的GST基因的全长cDNA序列。该基因被命名为PpGST（GenBank登录号为HQ889136）。PpGST全长cDNA为1 177 bp，具有130 bp 5′-UTR、696bp ORF以及351 bp 3′-UTR，编码含231个氨基酸的蛋白质。与已知植物GSTs家族成员间的氨基酸序列聚类分析将PpGST聚为zeta类GST。RT-PCR分析显示，PpGST在火把梨光照的果皮和没有光照的果皮中大量表达，并且表达强度不受光照时间的影响，而在幼嫩叶片中没有表达。研究结果暗示在果皮中大量表达的PpGST可能参与维持火把梨果实发育过程中的氧化还原平衡及应答逆境胁迫。
Abstract:Based on the EST sequence encoded the glutathione S-transferase (GST),gene-specific primers were designed and used to obtain the full-length cDNA of a novel GST gene from Pyrus pyrifolia Nakai cv.Huobali in Yunnan Province with the method of rapid amplification of cDNA ends (RACE).This novel gene was named as PpGST.PpGST is 1 177 bp in length with an ORF of 696 bp,a 5′-untranslated region (UTR) of 130 bp,and a 3′-UTR of 351 bp,and the ORF encodes a predicted polypeptide of 231 amino acids.A phylogenetic analysis of the relationship of the newly identified PpGST with some known plant GSTs grouped the PpGST into the class of zeta GSTs.PpGST is abundantly expressed in pericarps of Huobali regardless received sunlight or not,but no expression was detected in the young leaves.The abundant expression of PpGST in fruits of P.pyrifolia hints that the PpGST may be involved in maintaining the redox balance and stress response during the pear fruit development.