摘要：

WRKY是植物特有的一类转录因子,在非生物胁迫应答、种子休眠与发芽、生长发育等方面起重要作用。为揭示大豆WRKY转录因子家族中GmWRKY44基因的功能和潜在的分子机制,对大豆Williams 82中GmWRKY44基因进行了生物信息学分析及功能验证。结果表明,GmWRKY44基因CDS全长1 077 bp,编码358个氨基酸;结构预测与进化分析结果显示,其编码的蛋白质二级结构由23.46% α-螺旋、4.75% β-折叠、58.94%无规则卷曲和12.85%延伸链构成,三级结构与二级结构相统一;含一个保守的WRKY结构域,锌指结构为C₂H₂类型,属WRKY IIc亚家族;该基因是拟南芥AtWRKY71的同源基因,相似度为35.56%,两者具有相似的基因结构。RT-qPCR分析表明,GmWRKY44响应盐胁迫,表达量先下降后上升。在盐胁迫下,野生型(Col-0)和GmWRKY44过表达拟南芥株系的萌发率和根长均受到一定程度抑制,但GmWRKY44过表达株系明显优于Col-0。另外,在盐处理后,GmWRKY44过表达株系生长受抑制程度低于Col-0。生理指标分析发现,在盐胁迫下,GmWRKY44过表达株系的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著高于Col-0,而丙二醛(MDA)含量显著低于Col-0。以上表明,GmWRKY44过表达可以提高转基因拟南芥的耐盐性。

关键词: 大豆, GmWRKY44, 基因克隆, 生物信息学分析, 功能验证, 盐胁迫

Abstract:

WRKY is a unique class of transcription factors in plants,which plays an important role in plant abiotic stress response,seed dormancy and germination,growth and development,etc.In order to reveal the function and underlying molecular mechanism of GmWRKY44 gene in soybean WRKY transcription factor family,bioinformatics analysis and biology function verification of soybean Williams 82 GmWRKY44 were performed.GmWRKY44 gene was 1 077 bp in length and encoded 358 amino acids;the results of structural prediction and evolutionary analysis showed that,the secondary structure was composed of 23.46% α-helix,4.75% β-fold,58.94% irregular coil and 12.85% extended chain,and the tertiary structure was unified with the secondary structure;It contained a conserved WRKY domain, the zinc finger structure was of the C₂H₂ type, and it belonged to the WRKY IIc subfamily; GmWRKY44 is a homologous gene of Arabidopsis thaliana AtWRKY71 with a similarity of 35.56%, and the two genes had similar gene structures. RT-qPCR analysis showed that GmWRKY44 responded to salt stress and its expression level first decreased and then increased.Under salt stress,the germination rate and root length of wild-type(Col-0)and GmWRKY44 overexpressing Arabidopsis lines were inhibited to a certain extent,but GmWRKY44 overexpressing lines were significantly better than Col-0.In addition,under salt stress,the growth inhibition of GmWRKY44 overexpressing lines was lower than that of Col-0.Physiological index analysis revealed that under salt stress,the overexpression lines of GmWRKY44 exhibited significantly higher activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)than Col-0,while the content of malondialdehyde(MDA)was significantly lower than Col-0.These data indicated that overexpression of GmWRKY44 could improve salt tolerance in transgenic Arabidopsis.

Key words: Soybean, GmWRKY44, Gene cloning, Bioinformatics analysis, Function verification, Salt stress