Identification of novel rice (Oryza sativa) HPP and HIPP genes tolerant to heavy metal toxicity
Identification of novel rice (Oryza sativa) HPP and HIPP genes tolerant to heavy metal toxicity
复制标题
新型耐重金属毒性水稻HPP和HIPP基因的鉴定
DOI：
10.1016/j.ecoenv.2019.03.040
复制
发表时间：
2019-07-15
影响因子：
6.8
通讯作者：
Yang, Zhi Min
中科院分区：
文献类型：
--
作者：
Khan, Irfan Ullah;Rono, Justice Kipkoir;Yang, Zhi Min
HPP(重金属相关植物蛋白)和HIPP(重金属相关异戊二烯基化植物蛋白)是一类与金属结合的金属配位蛋白，在金属动态平衡和解毒中起着至关重要的作用。到目前为止，在植物中只有很少的功能基因被鉴定。在此，我们在水稻基因组中鉴定了54个HPP和HIPP基因。对镉胁迫下水稻基因组转录组数据的分析发现，17个HPP/HIPP基因差异表达，其中11个基因表达上调(>；2倍变化，p<；0.05)。通过qRT-PCR对转录产物的综合分析表明，在过量的锰、铜和镉胁迫下，这两种基因在水稻中表现出不同的表达模式。对HPPs/Hipps进行了多种基因组分析，包括系统发育、保守结构域和基序、基因组排列、基因组和串联复制。为了确定这些基因的作用，随机选择OsHIPP16、OsHIPP34和OsHIPP60在酿酒酵母突变株pmr1、CuP2、ycf1和ZRc1中表达，它们分别对锰、铜、镉和锌的毒性敏感。补充试验表明，转化细胞积累了更多的金属，但其生长状况有所改善。为了证实这一功能，在金属胁迫下对两个OsHIPP42表达缺陷的突变株oshipp42进行了鉴定。在正常条件下，oshipp42突变体和野生型植株的生长没有差异。在过量的铜、锌、镉和锰的作用下，oshipp42品系的生长弱于野生型。我们的工作提供了一个新的水稻重金属结合基因的来源，可以用于培育修复重金属污染土壤中植物的工程植物。
HPP (heavy metal associated plant protein) and HIPP (heavy metal associated isoprenylated plant protein) are a group of metal-binding metallochaperones playing crucial roles in metal homeostasis and detoxification. Up to now, only few of them have been functionally identified in plants. Here, we identified 54 HPP and HIPP genes in rice genome. Analysis of the transcriptome datasets of the rice genome exposed to cadmium (Cd) revealed 17 HPP/HIPP genes differentially expressed, with 11 being upregulated ( > 2 fold change, p < 0.05). Comprehensive analysis of transcripts by qRT-PCR showed that both types of genes displayed diverse expression pattern in rice under excess manganese (Mn), copper (Cu) and Cd stress. Multiple genomic analyses of HPPs/HIPPs including phylogenesis, conserved domains and motifs, genomic arrangement and genomic and tandem duplication were performed. To identify the role of the genes, OsHIPP16, OsHIPP34 and OsHIPP60 were randomly selected to express in yeast (Saccharomyces cerevisiae) mutants pmr1, cup2, ycf1 and zrc1, exhibiting sensitivity to Mn, Cu, Cd and Zn toxicity, respectively. Complementation test showed that the transformed cells accumulated more metals in the cells, but their growth status was improved. To confirm the functional role, two mutant oshipp42 lines defective in OsHIPP42 expression were identified under metal stress. Under normal condition, no difference of growth between the oshipp42 mutant and wild-type plants was observed. Upon excess Cu, Zn, Cd and Mn, the oshipp42 lines grew weaker than the wild-type. Our work provided a novel source of heavy metal-binding genes in rice that can be potentially used to develop engineered plants for phytoremediation in heavy metal-contaminated soils.