谷子PPDK2在非生物逆境胁迫下的表达分析

Expression Analysis of PPDK2 Gene under Abiotic Stress in Foxtail Millet

谷子是具有抗旱、耐瘠、抗逆性强、适应性广等特点的C4禾本科作物,发掘谷子高光效、逆境相关基因,旨在揭示谷子在光照和逆境胁迫下的基因表达特征。采用生物信息学方法,在谷子中鉴定出一个PPDK基因,命名为SiPPDK2;该基因位于谷子3号染色体,含有18个内含子,有3个转录本,原始转录本编码945个氨基酸。亚细胞定位预测结果显示,该基因位于叶绿体中。功能域分析和多序列比对发现,SiPPDK2蛋白与玉米、高粱和水稻PPDK蛋白的亲缘关系较近。Real-time PCR分析表明,PEG、ABA、盐和低温胁迫对苗期SiPPDK2基因表达有不同程度的诱导。进一步研究表明,SiPPDK2基因在拔节期、抽穗期和灌浆期均参与了对干旱和光照的胁迫响应,其中抽穗期和灌浆期在干旱条件下及拔节期和灌浆期在弱光条件下其表达量显著上调。顺式元件分析结果表明,在SiPPDK2启动子区域主要包括激素类应答、逆境应答、光应答以及其他类生长调控相关的顺式元件。结果推测,SiPPDK2基因可能参与了谷子对非生物逆境胁迫的响应。

Foxtail mille is a C 4 gramineous crop with drought resistance,barren-tolerance,wild adaptability and high adverse resistance.To reveal the role of the genes expression characteristics under light and stress of foxtail millet,the genes related to abiotic stress were explored in this experiment.A PPDK gene,named as SiPPDK2,was identified in foxtail millet genome by bioinformatics method.SiPPDK2 was located on chromosome 3 in foxtail millet genome,which contained 18 introns.It contained 3 transcripts and primary alternative transcript encoding 945 amino acids residues.Subcellular localization predictions indicated that SiPPDK2 was mainly localized in chloroplasts.Functional domain and multiple sequence alignment analysis revealed that SiPPDK2 protein had a more closely relationship with PPDK proteins in maize,sorghum and rice.RT-PCR analysis showed that the expression of SiPPDK2 at its seedling stage was induced by PEG,ABA,salt and low temperature treatments.Further studies indicated that SiPPDK2 was involved in drought stress and different light intensity at the jointing,heading and filling stage,in which the expression was significantly increased under the drought condition at heading and filling stages and under the low light condition at jointing and filling stage.cis-elements analysis revealed that hormonal,stress,light,and other growth-related responses cis-elements were present in the promoter region of the SiPPDK2.The results speculated that SiPPDK2 is involved in the response to abiotic stress in foxtail millet.