玉米磷转运蛋白基因ZmPht3;1的克隆和功能分析

Cloning and Characterization of ZmPht3;1,a Phosphate Transporter Gene in Maize

Pht3(phosphate transporter 3)磷转运子家族属于一类低亲和力磷转运蛋白,在调节植株体内磷素的动态平衡中发挥重要作用。为了初步探讨玉米中Zm Pht3;1基因的结构特征及其磷饥饿的响应机制,利用同源克隆的方法从耐低磷玉米自交系Mo17中分离得到Zm Pht3;1基因,并运用实时荧光定量PCR和亚细胞定位的方法对其进行深入研究。结果表明,Zm Pht3;1的编码区全长1 101 bp,编码366个氨基酸,含有典型的线粒体转运家族(mitochondrial carrier family,MCF)结构特征与6个疏水跨膜结构。荧光定量PCR分析表明,该基因在两个极端材料的根系与叶片中均有表达,而表达模式差异显著,在耐低磷玉米自交系Mo17的根系和叶片中表现为缺磷胁迫前期的一般性反应和后期的特异性反应。转化烟草的亚细胞定位结果显示,Zm Pht3;1主要分布于细胞膜上,可能是一个双亲和转运体,在玉米响应磷饥饿胁迫过程中发挥重要的适应性调节作用。

Pht3（phosphate transporter 3）family belonging to low-affinity phosphate transporters play an important role in the regulationof phosphorus homeostasis in plants. In order to explore the characterization of gene structure and response mechanism of Zm Pht3;1 tophosphorus（P）starvation,the gene Zm Pht3;1 was isolated from low-phosphorus（low-P）tolerance maize inbred line Mo17 by homologycloning. Then the quantitative real-time PCR and subcellular localization of Zm Pht3;1 were performed for further research in this study. Theresults showed that the complete CDS of Zm Pht3;1 was 1 101 bp encoding 366 putative amino acids in length,and contained 6 hydrophobictransmembrane domains and had a typical conservation structure domain of mitochondrial carrier family. The PCR results exhibited that the geneexpressed in roots and leaves,and the expression patterns were significantly different in the two extreme materials,respectively. While geneexpression pattern in low-P tolerance maize inbred line Mo17 both roots and leaves revealed general and special response to P deficiency stressin early and late stages,respectively. Subcellular localization in the transformed tobacco（Nicotiana benthamiana）showed that Zm Pht3;1mainly expressed in cytoplasm membrane and it was a phosphate transporter in both low-and high-P environment,and played a key role in theprocess of adapting to P starvation in maize.