miR3979在水稻砷耐受性中的作用

miR3979可能参与水稻Oryza sativa应答亚砷酸盐和过氧化氢胁迫,但其具体的生物学功能未知。以miR3979过表达转基因株系(As21-2,As21-3)和野生型品种中花11为试材,系统研究了转基因植株对亚砷酸盐的耐受性表现及其初步生理机制。结果表明:与野生型相比,miR3979过表达转基因植株对亚砷酸盐更加敏感,其对砷的吸收与转移能力明显增强;转基因植株在砷胁迫下,其根部脯氨酸、可溶性蛋白质量浓度显著升高,但各抗氧化酶活性却受到明显抑制,miR3979在亚砷酸盐处理后的野生型和转基因植株叶片中的表达谱截然不同。这些结果可为进一步揭示由该基因介导的水稻对砷耐性改变的分子机制以及抗逆育种提供理论参考。

miR3979-mediated arsenite tolerance in rice

It was reported that miR3979 might be involved in the responses to arsenite and hydrogen peroxide stresses in rice, but its biological function remains unclear. In this study, using transgenic plants overexpressing miR3979 As21-2 and As21-3, and wild-type (WT) Zhonghua 11 as materials, we investigated its physiological functions in response to arsenite stress in rice. The results showed that, compared with WT, transgenic plants were more sensitive to arsenite, which has a greater arsenic absorption and translocation. Under arsenite stress, the proline and soluble protein contents were significantly increased, while the activity of most of the antioxidant enzymes SOD, POD, APX, and CAT was inhibited extensively in roots of transgenic plants. Furthermore, it was found that miR3979 exhibited distinct gene expression profiles in leaves of WT and transgenic plants after exposure to arsenite. These results may be very significative for further investigation the molecular mechanisms of miR3979-mediated arsenic tolerance in rice, and also providing some useful clues for rice stress resistance breeding.