小麦黄色素合成途径中Psy基因的克隆及分子特性

Cloning and Molecular Characterization of Psy Gene in Wheat Yellow Pigment Biosynthesis

对普通小麦(Ttiticum aestivum)黄色素(YP)合成途径中的首要限速酶——八氢番茄红素合成酶(Psy)基因进行克隆和测序,并和玉米Psy基因进行序列比对。结果表明,在高和低YP含量小麦品种中均扩增出一条长1192bp的Psy基因片段,该片段包含一条可编码78个氨基酸的小麦Psy基因的外显子,与玉米Psy基因第4外显子的核苷酸序列同源率为80.74,同源区域内有47个SNPs,但仅11个SNPs导致氨基酸编码序列的改变,二者氨基酸序列的同源率达85.89,推测Psy基因在不同物种中的表达具有较高的保守性。BLAST聚类分析表明,禾谷类植物Psy基因的分类与物种的亲缘关系存在明显的相关性,小麦Psy基因在系统进化中比禾谷类其他植物更为高级。

Phytoene synthase （Psy） gene, a primary rate-limiting enzyme in the biosynthesis pathway of wheat yellow pigment （YP）, was cloned and sequenced in this study, at the same time, the Psy gene sequences between wheat and maize were compared. The results showed that, a 1 192 bp DNA fragment was amplified by polymerase chain reaction in DNA samples extracted from the high YP and low YP content wheat cultivar, the gene fragment contains a intact exon of Psy gene, which codes 78 amino acids. Sequence analysis showed that the wheat DNA fragment was closely homologous to those of the maize 4th exon, with homology rate of nucleotide and amino acids sequences at 80.74% and 85.89%. Although there were 47 SNPs in the homology area of wheat and maize, only 11 SNPs led to the variation of amino acid sequences, which indicates Psy gene was conservative in different species. Blast clustering analysis showed, the class of Psy gene was significantly related to their genetic relationship in gramineous plants, the Psy gene of wheat was more advanced than other cereal plants in system evolution.