谷子SiWRKY03基因的分子特征与表达分析

Molecular Characteristics and Expression Analysis of SiWRKY03 Gene in Foxtail Millet

WRKY是参与植物生长发育与抗逆反应的一类转录因子。为了解谷子中SiWRKY03基因的功能,利用生物信息学软件分析了其生物学特征,采用Real-time PCR技术检测了SiWRKY03转录因子在谷子不同组织部位和抗谷锈病过程中的表达丰度变化。结果表明,SiWRKY03基因的开放阅读框全长为1 137 bp,编码378个氨基酸,预测分子质量为39.73 ku,理论等电点(pI)为5.91,含有1个WRKY保守结构域。该蛋白质二级结构的最大元件是无规则卷曲,最小元件为β-转角。进化分析表明,SiWRKY03与糜子(RLM93064.1)和哈氏黍(PAN29607.1)的氨基酸序列同源性最高,为99%。组织表达分析表明,该基因在谷子根、茎、叶和穗中均有表达,其中根中表达量最高,穗中表达量最低,与转录组数据一致。在谷子响应锈菌胁迫反应的120 h内,SiWRKY03基因在抗病反应的12,36 h上调表达,而感病反应过程中无显著性变化,推测SiWRKY03在谷子抗锈病反应中起正调控作用。上述试验结果为进一步研究SiWRKY03基因功能与抗病机制奠定理论基础。

The WRKY transcription factor is involved in the developmental process and stress response of plant. To better understand the function of foxtail millet SiWRKY03 gene, its biological characteristics was analyzed by means of bioinformatics software. Real-time PCR was used to survey the expression profile in different tissues and the rust resistance response. The results showed that the open reading frame of SiWRKY03 gene contained 1 137 bp, encoding 378 amino acids with a WRKY conserved domain. The predicted protein molecular weight was 39.73 ku and the theoretical isoelectric point(pI) was 5.91. The largest secondary structure element of SiWRKY03 protein was random coil, and the smallest element was beta turn. Phylogenetic analysis showed that SiWRKY03 protein had 99% homology with those of Panicum miliaceum(RLM93064.1) and Panicum hallii(PAN29607.1). Expression patterns showed that SiWRKY03 gene of foxtail millet was expressed in roots, stems, leaves and panicles at booting stage, and the highest expression level was in roots and the lowest in panicles, which was consistent with the result of transcriptome data. During the responses to rust stress of foxtail millet, the expression of SiWRKY03 gene was up-regulated at 12,36 h in disease resistance response, but it had no significant change in the whole process of susceptible reaction, suggesting that SiWRKY03 played a positive regulatory role in the rust disease resistance of foxtail millet. The results provided a theoretical foundation for further study of the SiWRKY03 function and its resistance mechanism in foxtail millet.