玉米ZmENA1基因的克隆及其对金属离子的应答分析

Cloning of ZmENA1 and Its Responses to Metal Ions in Maize

烟酰胺(NA)是重要的植物铁载体麦根酸(MA)的前体物质,烟酰胺外排转运体ENA是植物体介导NA转运的重要蛋白。探究ZmENA1的基本功能可为阐明玉米中金属离子的转运及储存机制提供依据。本研究同源克隆了ZmENA1基因,并通过生物信息学方法分析了该蛋白的基本特征,同时运用实时荧光定量技术分析了该基因在籽粒发育过程及在不同金属离子浓度下的表达模式。结果表明,ZmENA1的ORF长1356 bp,预测其编码蛋白等电点为8.06,蛋白质大小为48.998 kD,在蛋白质二级结构中α螺旋占比达53.98%;该蛋白有4个磷酸化位点、10个跨膜区且N端含有1个信号肽。表达分析发现,ZmENA1在胚乳和种皮混合物中的表达量高于胚,并在16 DAP达到高峰,然后随着发育进程逐渐降低。此外,ZmENA1的表达可应答于Zn2+、Mn2+和Cu2+的缺乏以及过量的Zn2+、Mn2+和Cd2+,推测ZmENA1在调节金属离子的转运和储藏方面发挥作用。本研究为深入揭示ZmENA1的功能提供基础。

Nicotianamine(NA)is the precursor of mugineic acid(MA)which is a phytosiderophore of plants,and nicotianamine effluxer(ENA)is an important protein mediating NA transport in plants.Thus,exploring the functions of ZmENA1 may provide bases for understanding metal ions transport and storage mechanisms in maize.In this study,ZmENA1 was homologously cloned and the basic characteristics of the encoded protein were analyzed via bioinformatics.Also the expression patterns of ZmENA1 during kernel development process under different metal ions concentrations were examined using real-time quantitative PCR.The results showed that the ORF of ZmENA1 was 1356 bp,and the encoded protein had a deduced isoelectric point of 8.06 and molecular weight of 48.998 kD.In addition,ZmENA1 contained 53.98%proportion ofα-helix,four phosphorylation sites,10 transmembrane regions,and 1 N terminal signal peptide.The expression of ZmENA1 in the mixture of endosperm and pericarp was higher than that in the embryo,reached a peak at 16 DAP,and decreased with the developmental process.Besides,the expression of ZmENA1 presented fluctuations in response to deficiency of Zn2+,Mn2+,and Cu2+,as well as excess of Zn2+,Mn2+,and Cd2+,suggesting that ZmENA1 played a role in mediating transport and storage of these metal ions.This study may provide a basis for further revealing the function of ZmENA1.