小麦谷氨酰胺合成酶前体Ⅱ基因的克隆与分析

Cloning and Analysis of Glutamine SynthaseⅡ Precursor in Triticum aestivum L.

采用RACE方法,从小麦耐盐突变体RH8706-49的转录产物中获得谷氨酰胺合成酶Ⅱ(GS2)前体基因的全长cDNA序列,共包含1 690 bp,其中ORF区1 284 bp,编码427氨基酸。该基因已提交GenBank(登录号:DQ103756)。经Blast比对,该基因与大麦、水稻、玉米GS2的同源性分别达94.6%、87.0%和90.4%。经Northern blotting分析,发现GS2基因在小麦耐盐突变体RH8706-49和其同属”一粒传”后代的敏盐突变体H8706-34中盐胁迫前后均有表达,但前者高于后者。盐胁迫后二者的表达量均有所下降,不过在敏盐突变体中下降的更为明显,说明GS2基因是盐抑制基因,属于转录水平上的调控,且与小麦耐盐性密切相关。

In this study, we were cloned the sequence of glutamine synthoze 2 （ GS2 ） in the wheat salt-resistant mutant RH8706-49. It contains 1 690 bp and the coding sequence has 1 284 bp which can code 427 amino acid. We have submitted this gene to GenBank （Accession No. ： QD103756）. The coding area of GS2 in wheat showed 94.6%, 87.0% and 90.4% similarities with barley, rice and maize, respectively. The result of Northern blotting showed that GS2 expressed both in salt-resistant wheat RH8706-49 and salt-sensitive wheat H8706-34 which were the offsprings propagated by “One Seed” mutant. The expression of GS2 in RH8706-49 was obviously higher than that in H8706-34. The expression of GS2 was reduced by salt-stress, and the amount of GS2 reduced more in H8706-34. It is demonstrated that GS2 is a kind of salt-inhibitory gene and may be regulated at the transcription level.