玉米ZmWRKY53基因克隆及诱导表达分析

Cloning and Induced Expression Analysis of ZmWRKY53 in Zea mays

WRKY是植物细胞中进化较为保守的一类转录因子,参与了生物和非生物逆境胁迫应答反应的调控。本研究基于干旱诱导的玉米(Zea mays L.)B73转录组数据库,成功克隆到1个WRKY基因,命名为Zm WRKY53。序列比对发现,该基因含有904 bp的完整开放读码框,编码302个氨基酸,在C端含有1个保守的WRKYGQK结构域,同源比对ZmWRKY53属于IIc类WRKY转录因子。生物信息学预测,Zm WRKY53为碱性不稳定亲水性蛋白,无信号肽和跨膜结构域。洋葱内表皮亚细胞定位显示,Zm WRKY53蛋白位于细胞核中。实时荧光定量PCR(qRT-PCR)分析表明,Zm WRKY53基因在玉米的根和叶中有较高的表达水平,而在茎、玉米须、雄穗和胚中的表达量较低。不同的非生物胁迫如低温(8℃)、NaCl、H2O2和PEG均能显著提高Zm WRKY53的表达水平,尤其是PEG诱导使其表达水平上调9.5倍。接种玉米纹枯病的叶片中,Zm WRKY53的表达量提高了13倍。对比不同的激素处理情况,脱落酸(abscisic acid,ABA)和水杨酸(salicylic acid,SA)处理后,Zm WRKY53的表达水平持续上调;而在赤霉素(gibberellin,GA)和乙烯处理的玉米根中,Zm WRKY53呈现无规律的变化特征。蛋白互作预测,十个候选基因可作为后续Zm WRKY53调节机制的靶目标研究。上述实验表明,Zm WRKY53基因通过对不同激素信号的调节,不仅参与玉米对纹枯病的抗性反应,还参与对非生物胁迫信号的转导。

WRKY is one of conserved transcription factors in plant cells and is important for the regulation of diverse biotic and abiotic stresses.Based on the B73 transcriptome of maize(Zea mays L.),a WRKY gene was successfully cloned,named as Zm WRKY53,in our present study.Sequence analysis showed that the complete open reading frame of Zm WRKY53 was 904 bp,encoding 302 amino acid residues.The ZmWRKY53 protein contained a conserved WRKYGQK domain and belonged to IIc subgroup of WRKY transcription factor family by the homology alignment.Bioinformatics analysis showed that Zm WRKY53 was an alkaline unstable hydrophilic protein without the signal peptide and transmembrane structures.ZmWRKY53 was located in the nucleus after transient expression in onion epidermal cells.The quantitative real-time PCR(qRT-PCR)demonstrated that high transcription accumulation of Zm WRKY53 was det ected in roots and leaves,but lower expression levels were found in stems,tassels,silks and embryos.Different abiotic stresses such as low temperature(8℃),NaCl,H2 O2 and PEG up-regulated significantly expression levels of ZmWRKY53.Especially,9.5 fold increase was found in the maize roots after PEG treatment.Inoculation with the sheath blight induced 13 fold increase in leaves.Compared with different hormone treatments,expression levels of Zm WRKY53 were gradually up-regulated after treatments with abscisic acid(ABA)and salicylic acid(SA),while irregular changes were detected after gibberellin(GA)and ethylene treatments.Protein interaction prediction exhibited that ten candidate genes can be considered as ZmWRKY53 targets.The above results indicated that ZmWRKY53 not only participates in the resistance of maize to the sheath blight,but also plays a role in the regulation of abiotic stresses by different hormone pathways.