杨树重金属相关异戊二烯化植物蛋白(HIPPs)基因的鉴定及表达分析

金属伴侣在植物的生理活动中发挥关键作用,负责结合金属离子并将其转运至靶蛋白以维持细胞的金属离子稳态。目前关于HIPP （heavy metal-associated isoprenylated plant protein）金属伴侣蛋白的特性和功能分析多集中于模式植物拟南芥。本研究在毛果杨（Populus trichocarpa）中鉴定了14个PtHIPPs蛋白,均具有两个保守的金属离子结合基序MXCXXC,氨基末端可以形成βαββαβ二级结构,羧基末端具有保守的异戊二烯化基序;一些PtHIPPs还具有赖氨酸和/或甘氨酸富集区。根据基因结构、蛋白质的保守基序和进化树分析,PtHIPPs蛋白可分为3个亚组。PlantGenIE的组织特异性表达数据及荧光定量PCR鉴定结果显示,毛果杨PtHIPPs基因及小黑杨（Populus simonii×Populus nigra）PnHIPPs基因具有特定的组织表达特异性且存在差异。此外,利用缺铜及过量铜离子处理小黑杨植株不同时间后,不同组织部位中PnHIPPs基因的表达模式发生改变。本研究为鉴定木本模式植物杨树HIPPs蛋白在维持铜离子稳态过程中发挥的作用提供了参考依据。

Identification and Expression Analysis of Heavy Metal-associated Isoprenylated Plant Proteins(HIPPs) Genes in Populus

Metal chaperones play key roles in plant physiological activities, and could bind metal ions and transport them to target proteins in order to maintain the metal ions homeostasis of cells. Currently, the properties and function analysis of the metal chaperones HIPP (heavy metal-associated isoprenylated plant protein) is mostly limited to the model plant Arabidopsis thaliana. In this study, 14 PtHIPPs were identified in Populus trichocarpa, all of which had two conserved metal ion binding motif MXCXXC, as well as the conserved isoprenylation motif in the carboxyl terminal. The amino terminal of PtHIPPs was form the βαββαβ secondary structure. Some PtHIPPs had lysine-rich and/or glycine-rich regions. PtHIPPs proteins could be divided into three subgroups according to gene structure, protein conservation motifs and phylogenetic analysis. The tissue-specific expression data of PlantGenIE and the results of fluorescence quantitative PCR identification showed that PtHIPPs genes of P.trichocarpa and PnHIPPs genes of Populus simonii×Populus nigra had tissue-specific expression characterizations and differences. In addition, the expression patterns of PnHIPPs in different tissues of P.simonii×P.nigra seedlings were changed after treated with copper deficiency or copper excess conditions for different times. This study provided theoretical groundwork for identifying the roles of HIPPs proteins in maintaining copper homeostasis in woody model plant Populus.