Agricultural College of Ningxia University/Key Laboratory of Modern Molecular Breeding of Dominant Characteristic Crops in?Ningxia
State Natural Sciences Foundation (31560297)
为探究盐胁迫下OsDSR2 RNAi转基因水稻的生理特性和差异基因的表达调控，以野生型中花11(ZH11) 植株为对照，对盐胁迫下OsDSR2 RNAi转基因水稻幼苗进行生理指标测定和转录组学分析，结果表明：正常条件下, ZH11和OsDSR2 RNAi转基因水稻中的各项生理指标均没有显著性差异，而盐胁迫处理后，OsDSR2 RNAi转基因水稻中的叶绿素含量、可溶性糖（SS）含量、超氧化物歧化酶（SOD）活性、过氧化氢酶（CAT）活性与ZH11相比没有明显变化，但转基因植株中的细胞膜透性、丙二醛（MDA）含量、Na+/K+明显低于ZH11，脯氨酸（Pro）含量、过氧化物酶（POD）活性明显高于ZH11。OsDSR2 RNAi转基因植株在盐胁迫前后共产生68个差异表达基因，其中有55个上调表达，13个基因下调表达。GO分析结果显示，差异表达基因主要富集在胁迫应激反应、分解代谢等生物学过程中。KEGG分析结果表明，差异表达基因主要参与类胡萝卜素生物合成、油菜素内酯生物合成以及表皮素，软木脂和蜡质生物合成代谢通路,进一步通过RT-qPCR验证了OsbZIP16、OsLEA3、RAB21等逆境胁迫相关基因参与水稻的胁迫应答反应。综上，在生理层面上，OsDSR2 RNAi转基因水稻植株主要通过降低细胞膜透性、MDA含量和Na+/K+，增加Pro和POD活性，抑制叶绿素的降解来提高耐盐性；在分子水平上，OsDSR2通过ABA（脱落酸）、BR（油菜素内酯）信号通路参与调控OsLEA3、RAB21、OsbZIP16等逆境相关基因以及植物表皮蜡质生物合成相关基因（LOC_Os04g28620）的表达来提高苗期水稻的耐盐性，为进一步阐明OsDSR2参与调控水稻耐盐的详细分子机制奠定了基础。
In order to explore the physiological characteristics and the transcriptional regulation of OsDSR2 RNAi transgenic rice under salt stress, we analyzed the physiological indicators and the transcriptome profiles of OsDSR2 RNAi transgenic rice seedlings compared to wild type Zhonghua 11(ZH11) plants. Analysis of the various physiological indexes under normal conditions revealed no significant difference in OsDSR2 RNAi transgenic line and ZH11. Under salt stress treatments, no significant difference on the content of chlorophyll, soluble sugar (SS), superoxide dismutase (SOD) activity and catalase (CAT) activity of OsDSR2 RNAi transgenic rice to ZH11 was detected, while the content of cell membrane permeability, malondialdehyde (MDA) and Na+/K + in transgenic rice were detected to be significantly lower; the content of Proline (Pro) and peroxidase (POD) activity were significantly higher than those of ZH11. The transcriptome analysis revealed 68 differentially expressed genes in OsDSR2 RNAi transgenic plants before and after salt stress treatment, 55 genes of which were up-regulated and 13 genes of which were down-regulated. GO analysis showed that the differentially expressed genes were enriched in stress response, catabolism and other biological processes. KEGG analysis showed that the differentially expressed genes were mainly involved in the biosynthesis of carotenoids, brassinolactone and the biosynthesis of epidermal, cork and wax biosynthesis pathways. The differential expression of OsbZIP16, OsLEA3, RAB21 and other stress-related genes under treatments was further verified by RT-qPCR. Taken together, the OsDSR2 RNAi transgenic rice plants showed the salt tolerance which might be associated with the reduction of the cell membrane permeability, the content of MDA and Na+/K +, the Pro and POD activities as well as the inhibition of the chlorophyll degradation. Furthermore, OsDSR2 gene might be also involved in the transcriptional regulation of OsLEA3, RAB21, OsbZIP16 and plant cuticular wax biosynthesis gene (LOC_Os04g28620).