School of Agriculture, Ningxia University, Yinchuan, 750021, China.
College of Life Sciences, Northwest Normal University, Lanzhou, 730070, China.
J Plant Physiol. 2023 Mar;282:153927. doi: 10.1016/j.jplph.2023.153927. Epub 2023 Jan 19.
Rice is a crucial staple food crop in many countries, yet, abiotic factors like salt and drought impact its growth. The Domain of Unknown Function 966 (DUF966) gene family may be crucial in how rice plants respond to abiotic stress. Our earlier research showed that overexpression of OsDSR2 (DUF966-stress repressive gene 2 in Oryza sativa) decreased resistance to salt and drought stress. To further understand how OsDSR2 negatively affects rice tolerance to salt and drought stress, transgenic rice plants with decreased OsDSR2 expression levels were created employing the RNAi technique. We investigated alterations in rice phenotype, physiology, and differentially expressed genes (DEGs) using a combination of physio-biochemical measurement and RNA-seq analysis. The results of the study demonstrated that rice seedling lines with OsDSR2 knockdown exhibited improved salt and drought stress tolerance. Statistical analysis revealed that the transgenic plants' survival rate (56-68%) was higher than the control plants (30%), in addition to a roughly 3 fold, 3.5 fold, 20% and 10.5% reduction in cell membrane permeability, malondialdehyde (MDA), superoxide anion radical (O) and hydrogen peroxide (HO) contents, respectively. However, the proline content and antioxidant enzymes (superoxide dismutase (SOD) and peroxidase (POD)) activities were considerably increased by about 5.5 fold, 3.5 fold, and 4.5 fold, respectively, at physiological levels. There were 115 up-regulated and 173 down-regulated DEGs in the leaves of the transgenic lines on the transcriptional regulation under the combined salt-drought stress. Among these, both up-regulation DEGs (e.g., OsHAK5, OsIAA25) and the down-regulation DEGs (e.g., OsbZIP23, OsERF48, OsAP2-39, etc.) may be related to the enhanced tolerance of the transgenic lines under combined salt-drought stress. This possibly depended on the involvement of abscisic acid (ABA) and indoleacetic acid (IAA) signaling pathways. These findings further confirmed that OsDSR2 negatively affected rice's ability to withstand salt and drought, suggesting that it could be a helpful gene for CRISPR-Cas9 technology-based genetic modification of rice's ability to withstand abiotic stress.
水稻是许多国家的重要主食作物，但盐和干旱等非生物因素会影响其生长。未知功能域 966（DUF966）基因家族在水稻植物对非生物胁迫的反应中可能很重要。我们之前的研究表明，过表达 OsDSR2（水稻中的 DUF966-应激抑制基因 2）会降低对盐和干旱胁迫的抗性。为了进一步了解 OsDSR2 如何负调控水稻对盐和干旱胁迫的耐受性，我们利用 RNAi 技术创建了 OsDSR2 表达水平降低的转基因水稻植株。我们结合生理生化测量和 RNA-seq 分析，研究了水稻表型、生理和差异表达基因（DEGs）的变化。研究结果表明，敲低 OsDSR2 的水稻幼苗系表现出对盐和干旱胁迫的耐受性提高。统计分析表明，与对照植株（30%）相比，转基因植株的存活率（56-68%）更高，细胞膜渗透率、丙二醛（MDA）、超氧阴离子自由基（O）和过氧化氢（HO）含量分别降低了约 3 倍、3.5 倍、20%和 10.5%。然而，脯氨酸含量和抗氧化酶（超氧化物歧化酶（SOD）和过氧化物酶（POD））的活性分别显著增加了约 5.5 倍、3.5 倍和 4.5 倍。在盐旱胁迫下，转基因系叶片的转录调控中有 115 个上调和 173 个下调的 DEGs。在这些 DEGs 中，上调的 DEGs（如 OsHAK5、OsIAA25）和下调的 DEGs（如 OsbZIP23、OsERF48、OsAP2-39 等）可能与转基因系在盐旱胁迫下的增强耐受性有关。这可能依赖于脱落酸（ABA）和吲哚乙酸（IAA）信号通路的参与。这些发现进一步证实，OsDSR2 负调控水稻的耐盐和耐旱能力，表明它可能是基于 CRISPR-Cas9 技术的水稻耐非生物胁迫遗传改良的有用基因。
