小麦转录因子基因TaWRKY46的克隆与表达分析

Cloning and Expression Profiles of TaWRKY46,a WRKY Type Transcription Factor Gene in Wheat(Triticum aestivum L.)

在富集低磷胁迫特异表达基因的小麦根系cDNA差减杂交文库中,鉴定了1个小麦WRKY型转录因子基因(TaWRKY46)。依据该基因的cDNA序列,在石新828中克隆了该基因。TaWRKY46的cDNA长度为872 bp,开放阅读框为669 bp,编码222个氨基酸残基,氨基酸组成上含有保守的WRKY基序和C2H2基序。系统进化分析表明,TaWRKY46与大麦WRKY34可能来自相同的祖先。与对照供磷水平(2 mmol/L Pi)相比,低磷处理(20μmol/L Pi)使根系中TaWRKY46的转录本数量明显增多,表明TaWRK46对低磷胁迫逆境产生了明显应答。此外,TaWRKY46对氮、钾、锌和钙养分胁迫也表现明显的上调表达特征。表明该基因编码蛋白在介导上述养分逆境信号的转导中具有重要作用。此外,TaWRKY46对干旱、盐分等非生物逆境和脱落酸(ABA)也产生明显应答。因此,TaWRKY46是小麦种属中应答多种非生物逆境的重要调控转录因子,在增强小麦抵御养分胁迫和非生物逆境的能力中可能具有重要作用。

One WRKY type transcription factor gene designated as TaWRKY46 was identified in a root subtractive cDNA library in which the differential expressed genes responding to the low-Pi stress were enriched.Based on the cDNA sequence of TaWRKY46,this gene was cloned in wheat cultivar Shixin828.The cDNA of TaWRKY46 was 872 bp in length,with an open reading frame of 669 bp and an encoded polypeptide of 222 aa.TaWRKY46 contains a conserved WRKY motif and a C2H2 conserved domain.Phylogenetic analysis displays a high similarity between TaWRKY46 and HvWRKY34,a WRKY transcription family gene in barley,suggesting them to be possibly derived from a same ancestor.Compared with those in sufficient-P（2 mmol/L Pi） condition,the transcripts of TaWRKY46 in roots under the deficient-P（20 μmol/L Pi） condition were dramatically increased,suggesting that TaWRKY46 gene was involved in the response to low P stress in the plants.In the meantime,TaWRKY46 was also obviously responding to the deficiencies of nitrogen,potassium,zinc,and calcium,as well as to be markedly up-regulated by other abiotic stresses,such as drought,salinity,and abscisic acid（ABA）.Therefore,TaWRKY46 has potential roles in regulating plant adaptation to nutrition deficiencies and other abiotic stress,such as drought and salinity in wheat.