Noble Research Institute, LLC, Ardmore, Oklahoma 73401, USA.
Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, Oklahoma 73401, USA.
Plant Physiol. 2022 Jun 1;189(2):988-1004. doi: 10.1093/plphys/kiac078.
As a major adverse environmental factor in most parts of the world, drought causes substantial crop yield losses. Rice (Oryza sativa) is one of the staple foods for more than one-half of the world's population. Rice plants are sensitive to even mild drought stress and need almost twice the amount of water compared to wheat (Triticum aestivum) or maize (Zea mays). Arabidopsis (Arabidopsis thaliana) small GTPase Nucleolar GTP-binding protein 1 (AtNOG1) plays a role in biotic stress tolerance. Here, we created transgenic rice lines constitutively overexpressing AtNOG1-1 or AtNOG1-2. We also developed rice RNA interference (RNAi) lines that show downregulation of OsNOG1. AtNOG1-1 and AtNOG1-2 overexpressors showed enhanced drought tolerance without compromising grain yield, whereas OsNOG1-RNAi was more susceptible to drought when compared to wild-type plants. Analysis of physiological parameters showed increased cell sap osmolality, relative water content, and abscisic acid (ABA) level, but decreased leaf water loss in AtNOG1-1 or AtNOG1-2 overexpressor lines compared to the control. We found upregulation of several genes involved in ABA and jasmonic acid (JA) signaling, stomata regulation, osmotic potential maintenance, stress protection, and disease resistance in AtNOG1-1 and AtNOG1-2 overexpressor lines compared to the control. We elucidated the role of NOG1-2 and NOG1-1 in regulation of silica body formation around stomata to prevent transpirational water loss. These results provide an avenue to confer drought tolerance in rice.
作为世界上大部分地区的主要不利环境因素，干旱导致大量作物减产。水稻（Oryza sativa）是全球一半以上人口的主食之一。与小麦（Triticum aestivum）或玉米（Zea mays）相比，水稻植株对轻度干旱胁迫非常敏感，需要的水量几乎是它们的两倍。拟南芥（Arabidopsis thaliana）小分子 GTP 酶核仁 GTP 结合蛋白 1（AtNOG1）在生物胁迫耐受中发挥作用。在这里，我们创建了组成型过表达 AtNOG1-1 或 AtNOG1-2 的转基因水稻品系。我们还开发了水稻 RNA 干扰（RNAi）系，该系表现出 OsNOG1 的下调。与野生型植物相比，AtNOG1-1 和 AtNOG1-2 过表达植株在不影响籽粒产量的情况下表现出增强的耐旱性，而 OsNOG1-RNAi 对干旱更敏感。对生理参数的分析表明，与对照相比，AtNOG1-1 或 AtNOG1-2 过表达系的细胞液渗透压、相对水含量和脱落酸（ABA）水平升高，但叶片水分损失减少。我们发现，与对照相比，AtNOG1-1 和 AtNOG1-2 过表达系中参与 ABA 和茉莉酸（JA）信号转导、气孔调节、渗透势维持、应激保护和抗病性的几个基因上调。我们阐明了 NOG1-2 和 NOG1-1 在调节围绕气孔的硅体形成以防止蒸腾失水方面的作用。这些结果为在水稻中赋予耐旱性提供了途径。
