一个水稻铁转运基因(OsFRDL1)参与缺氧诱导根系铁膜形成的调节过程  

A gene encoding an iron transport protein in rice(OsFRDL1) participates in regulating stagnancy-induced iron plaque formation on the root

作　　者：沈宏[1] 杨旭健[1] 傅友强[1] 

机构地区：[1]华南农业大学资源环境学院根层调控实验室,广州510642

出　　处：《科学通报》2014年第9期787-795,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(31071847,31372125);日本学术振兴会(JSPS-N08552);人事部留学回国人员择优资助项目(人社厅2010-412);广东省高等学校高层次人才项目(粤教师函2010-79号)资助

摘　　要：根表铁膜是水稻重要的养分库和抵抗环境胁迫的天然屏障．然而根表铁膜形成的分子机制并不清楚．本文以日本晴野生型对照及Osfrdll突变体为材料，研究了OsFRDLl基因在水稻根表铁膜形成中的作用．结果发现，低磷（〈0．02mmol L^-1）是水稻根表铁膜形成的重要条件．当处理溶液pH为5．0～6．0，FeS04浓度为30～50μmaol L^-1时，根表铁膜含量最大．与通气处理相比，缺氧处理降低水稻根表铁膜含量；且缺氧处理时，Osfrdll突变体根表铁膜含量低于野生型．实时定量PCR结果表明，缺氧处理显著增加OsFRDLl基因在根系表达，且根系基部的表达强度高于根尖．OsFRDL1：：GUS染色结果表明，OsFRDL1：：GUS报告基因主要在根系表皮细胞和维管束细胞表达；缺氧处理增加了报告基因在上述位置的表达．缺氧处理时，野生型比Osfrdl突变体根系具有较高的过氧化物酶活性．上述结果表明，缺氧处理诱导OsFRDL1基因的高量表达，使野生型与突变体相比，过氧化物酶活性维持较高的水平，从而使其铁膜生成量高于突变体．Iron plaques that form on the surface of roots serve as an important nutrient reservoir and as a natural barrier for rice （Oryza sativa） seedlings to adapt to environmental stress. However, the molecular mechanism of iron plaque formation is poorly understood. In this study, the Osfrdll mutant and its wild-type （Nipponbare） cultivar were used to explore the role of the OsFRDL1 gene in iron plaque formation on rice roots. The results showed that a low phosphorus concentration （〈0.02 mmol L 1） was an important factor for iron plaque formation. The maximum iron plaque formation on roots occurred when the pH value of the nutrient solution was between 5.0 and 6.0 and the FeSO4 concentration was between 30 and 50 grnol L-1. Compared with rice seedlings in the aerated treatment, those in a stagnant treatment showed significantly decreased iron plaque formation on the root surface. Furthermore, iron plaque formation was lower on roots of the Osfrdll mutant than on those of the wild-type. The results of real-time RT-PCR analyses indicated that the stagnant treatment increased the expression of OsFRDL1. As well, OsFRDLI：：GUS staining indicated that the GUS reporter gene was mainly expressed in epidermis cells and stele tissues in the root. The expression of the reporter gene in these tissues was markedly higher in seedlings in the stagnant treatment than in those in the aerated treatment. In the stagnant treatment, the peroxidase activity was higher in roots of wild-type plants than in those of the Osfrdll mutant. Taken together, these results suggest that the stagnant treatment induced increased expression of OsFRDL1. This increased the peroxidase activity to a higher level in the wild-type than in the mutant, and promoted greater iron plaque formation on the roots.

关 键 词：水稻 铁膜 Osfrdl1突变体 缺氧 过氧化物酶 

分 类 号：S511[农业科学—作物学]