谷子ABF3基因对PEG胁迫的响应

The Response of ABF3 Gene to PEG Stress in Foxtail Millet(Setaria italica L.)

ABF/AREB转录因子在植物抗旱调控途径中起着重要的作用,ABF3主要参与ABA胁迫应答。利用拟南芥ABF3基因序列从谷子基因组中比对获得同源ABF3基因序列。该基因有2种可变剪接形式,分别编码由354个和357个氨基酸残基组成的蛋白质,分子量和等电点分别为38153.65Da、38234.68Da和9.27、6.48。采用实时荧光定量PCR分析SiABF3基因表达,发现该基因在抗旱品种勾勾母鸡咀和干旱敏感品种青谷1号中的表达存在显著差异。抗旱品种在20%PEG-6000模拟干旱胁迫0.5h时,mRNA转录水平达到峰值;干旱敏感品种在干旱胁迫2h时SiABF3基因表达达到最高值。转录因子基因SiABF3在干旱胁迫初期的快速表达可能与谷子抗旱性有着紧密的联系。

ABF/ABRE binding factors play an important role in regulatory pathways of drought tolerance in plants.ABF3 is mainly involved in ABA stress response.In this study,ABF3 gene sequence in foxtail millet（SiABF3） was obtained by searching the genome and comparing the sequence alignment with Arabidopsis ABF3.It has two alternative splicing forms which were responsible for encoding proteins with 354 and 357 amino acids.The molecular weight and isoelectric point of the proteins of those two forms were about 38153.65 Da,38234.68 Da,and 9.27,6.48,respectively.Fluorescence quantitative RT-PCR system was established to analyze the expression of SiABF3under the 20 % PEG-6000 stress with foxtail millet varieties GG（drought tolerance） and QG1（drought sensitive）.The results showed the significant difference between GG and QG1.The mRNA transcriptional level reached the peak at 0.5 h under drought stress in GG,which was 68.36 folds compared with that of the QG1 in which the gene expression level reached the high level at 2 h.The dramatic increase in the expression of SiABF3at early stage under drought stress may be linked to drought tolerance.