OsIMA1增强水稻对镉逆境的适应性

OsIMA1 enhances tolerance to cadmium stress in rice

关键词:  水稻, OsIMA, Cd, Fe, 拮抗作用

Key words:  rice, OsIMA, cadmium, iron, antagonism

摘要:

铁(Fe)是植物生长发育所必需的营养元素而镉(Cd)是对植物有害的元素且对植物Fe和Cd的吸收存在拮抗作用。OsIMA是一类正调控水稻Fe吸收的一类小肽,其过表达可以促进Fe的积累。为探究OsIMA是否参与水稻对Cd胁迫的适应性,该研究以水稻为研究材料,利用荧光定量PCR分析了OsIMA基因的表达水平,通过遗传转化和CRISPR/Cas9基因编辑技术构建了OsIMA1过表达植物和ima1突变体植物,评估了OsIMA1过表达和突变体植物在Cd逆境条件下的株高,并利用电联耦合等离子体质谱法测量了根和地上部的Fe和Cd含量。结果表明:(1)Cd处理后,OsIMA1和OsIMA2的转录水平上调。(2)OsIMA1过表达植物比野生型植物对Cd胁迫更耐受。(3)ima1功能缺失突变体比野生型植物对Cd胁迫更敏感。(4)OsIMA1过表达植株根系的Cd含量较高,而ima1突变体植株地上部的Cd含量较高。综上所述,OsIMA1通过限制Cd从根向地上部的转运以增强水稻对Cd逆境的适应能力,该研究结果为定向培育耐Cd作物提供了理论参考。

Abstract:

Iron(Fe)is crucial for the growth and development of plants and cadmium(Cd)is toxic to plants. There is an antagonistical mechanism between Fe and Cd uptake in plants. OsIMAs are a class of small peptides, and their overexpression improves Fe accumulation in rice. To explore the role of OsIMA genes in response to Cd stress, we analyzed the expression of two OsIMA genes by qRT-PCR, generated OsIMA1 overexpression plants and CRISPR/Cas9 edited ima1 mutants by genetic transformation, assessed the plant heights of OsIMA1 overexpressing plants and ima1 mutant plants under Cd stress, and measured the Fe and Cd concentration of root and shoot. The results were as follows:(1)Transcriptional levels both OsIMA1 and OsIMA2 were up-regulated by Cd treatment.(2)Overexpression of OsIMA1 gene improved the tolerance of plants to Cd stress.(3)The loss-of-function of OsIMA1 led to the higher sensitivity of plants to Cd stress.(4)OsIMA1 overexpressing plants accumulated more Cd in the root and the ima1 mutants accumulated more Cd in the shoot. To sum up, OsIMA1 improves Cd tolerance by restricting Cd translocation from root to shoot, which provides the theoretical reference for breeding the Cd-tolerant rice.