采后荔枝果皮中谷胱甘肽转移酶基因的表达与酶活分析

Expression Analysis and Determination of Enzyme Activity of the Gultathione Transferase Gene from Postharvest Litchi Pericarp

为探明荔枝谷胱甘肽转移酶基因(Lc GST)的表达与果皮褐变之间的关系,在荔枝c DNA芯片中获得了荔枝Lc GST全长c DNA序列(ABR15777)。该序列全长913 bp,5′-UTR长53 bp,3′-UTR长215 bp,含一个645 bp的完整开放阅读框,编码含214个氨基酸残基的多肽。该氨基酸残基序列与沙梨等物种的谷胱甘肽转移酶蛋白相似性较高。基因表达分析表明,Lc GST在常温储存条件下基因的最大表达量出现在24 h,在保湿储存条件下,Lc GST的最大表达量出现在48 h。GST酶活性测定结果表明,在常温储存条件下酶活性的最大值出现在24 h,在保湿储存条件下酶活性的最大值出现在48 h。说明Lc GST在荔枝果皮褐化过程中起重要作用。

The relationship between postharvest browning and the expression of gultathione transferases （GST） gene （LcGST） in litchi pericarp was discussed in this work.The LcGST was obtaind from cDNA chip of Litchi.The full-length cDNA sequence of LcGST was 913 bp in length,contained a 53 bp 5＇-UTR,a 215 bp 3＇-UTR and a 645 bp open reading frame （ORF）,which encoded a 214 amino acid polypeptide.The deduced amino acid sequence of LcGST had high identities with GST protein from Pyrus pyrifolia.RT-PCR analysis showed that the maximum expression was in 24 hours under the normal temperature storage; under the moisture storage,the maximum expression was in 48 hours.The results of GST enzyme activity showed that the maximum of enzyme activity was in 24 hours under the normal temperature storage and 48 hours under the moisture storage.The results showed that GST gene plays an important role in the litchi pericarp browning.