摘要
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个与拟南芥WRKY75同源的小麦WRKY型转录因子基因表达序列标签(EST)。依据该EST序列高度同源的小麦WRKY72b序列,克隆了对应基因TaWRKY72b-1。TaWRKY72b-1与WRKY72b在cDNA序列上有2个碱基的差异,但编码氨基酸没有改变。TaWRKY72b-1开放阅读框为621bp,编码206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,TaWRKY72b-1与小麦WRKY72a和大麦WRKY12可能来自相同的祖先。与对照供磷水平(2mmol L-1P)相比,低磷处理使根叶中TaWRKY72b-1的转录本数量均明显增多。表明TaWRKY72b-1对低磷胁迫逆境产生了明显的应答作用。TaWRKY72b-1在烟草中表达表明,低磷胁迫条件下,高表达TaWRKY72b-1的烟草植株干重、单株磷累积量和磷利用效率均较对照明显增加。因此,TaWRKY72b-1基因在改善低磷胁迫下作物的磷效率中可能具有较重要的应用价值。
Phosphorus is one of the indispensable elements in plant growth and development, which is the main component for ATP, nucleic acid, and lecithin. Since phosphorus usually exists in the hard-absorption compounds in soil to cause plant suffering from phosphorus deficiency during growing stage. So plant morphological and physiologically develops the adaptation to low phosphorus stress. Transcription regulation plays an important role in responding to deficient-P cue in plants. Several transcription factors mediating the deficient-P signal transduction have been reported in Arabidopsis and rice. But no similar studies have been conducted in wheat by now. In this study, an expressed sequence tag （EST） homologous to Arabidopsis WRKY75 was identified based on sequencing of clones from a subtractive root cDNA library, in which the differential expressed genes responding to low-P were enriched. The EST gene with high similarity to wheat WRKY72b （GenBank accession No. EF368383）, was cloned and referred to TaWRKY72b-1. TaWRKY72b-1 had two base differences with WRKY72b at the cDNA sequence, with an open reading frame （ORF） of 621 bp and encoding a polypeptide of 206 amino acids. TaWRKY72b-1 contained one of conserved WRKY motif and one of C2H2 zinc finger motif. Phylogenetic tree analysis indicated that TaWRKY72b-1, wheat WRKY72a and barley WRKY12 were possibly derived from one ancestor. Compared with those in suffieient-P （2 mmol L^-1 P） condition, the transcripts of TaWRKY72b-1 in roots and leaves under the deficient-P （20 μmol L^-1 P） condition were all dramatically increased, suggesting that TaWRKY72b-1 gene was involved in the response to low P stress in the plants. Under deficient-P condition, the expression of TaWRKY72b-1 in transgenic tobacco plants obviously increased plant dry weights, plant accumulative phosphorus amount, and phosphorus utilization efficiency compared with that in CK （empty vector transformed plants）. Therefore, the TaWRKY72b-1 gene has possibly a potential use in improving the crop phosphorus use efficiency under low-Pi stress condition.
出处
《作物学报》
CAS
CSCD
北大核心
2009年第11期2029-2036,共8页
Acta Agronomica Sinica
基金
国家重点基础研究发展计划(973计划)前期(2007CB1162090)项目
河北省重点基础研究项目(08965525D)资助
