Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, P. R. China.
Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, 350002, P. R. China.
BMC Plant Biol. 2020 May 26;20(1):236. doi: 10.1186/s12870-020-02446-9.
Rice is a chilling-sensitive crop that would suffer serious damage from low temperatures. Overexpression of the Lsi1 gene (Lsi1-OX) in rice enhances its chilling tolerance. This study revealed that a serine hydroxymethyltransferase (OsSHMT) mainly localised in the endoplasmic reticulum (ER) is involved in increasing tolerance to chilling.
A higher transcription level of OsSHMT was detected in Lsi1-OX rice than in the wild type. Histone H1 and nucleic acid binding protein were found to bind to the promoter region of OsSHMT and regulate its expression, and the transcription levels of these proteins were also up-regulated in the Lsi1-OX rice. Moreover, OsSHMT interacts with ATP synthase subunit α, heat shock protein Hsp70, mitochondrial substrate carrier family protein, ascorbate peroxidase 1 and ATP synthase subunit β. Lsi1-encoded protein OsNIP2;1 also interacts with ATP synthase subunit β, and the coordination of these proteins appears to function in reducing reactive oxygen species, as the HO content of transgenic OsSHMT Arabidopsis thaliana was lower than that of the non-transgenic line under chilling treatment.
Our results indicate that ER-localised OsSHMT plays a role in scavenging HO to enhance the chilling tolerance of Lsi1-OX rice and that ATP synthase subunit β is an intermediate junction between OsNIP2;1 and OsSHMT.
水稻是一种对低温敏感的作物，低温会对其造成严重损害。Lsi1 基因（Lsi1-OX）在水稻中的过表达增强了其对低温的耐受性。本研究表明，一种主要定位于内质网（ER）的丝氨酸羟甲基转移酶（OsSHMT）参与提高对低温的耐受性。
在 Lsi1-OX 水稻中，OsSHMT 的转录水平高于野生型。发现组蛋白 H1 和核酸结合蛋白结合到 OsSHMT 的启动子区域并调节其表达，并且这些蛋白质的转录水平在 Lsi1-OX 水稻中也上调。此外，OsSHMT 与 ATP 合酶亚基α、热休克蛋白 Hsp70、线粒体底物载体家族蛋白、抗坏血酸过氧化物酶 1 和 ATP 合酶亚基β相互作用。Lsi1 编码的蛋白 OsNIP2;1 也与 ATP 合酶亚基β相互作用，这些蛋白质的协调似乎在减少活性氧方面起作用，因为在低温处理下，转 OsSHMT 拟南芥的 HO 含量低于非转基因系。
我们的结果表明，定位于 ER 的 OsSHMT 发挥清除 HO 的作用，增强 Lsi1-OX 水稻的低温耐受性，并且 ATP 合酶亚基β是 OsNIP2;1 和 OsSHMT 之间的中间连接点。
