Tongji University, No. 1239 Siping Road, Shanghai, 200092, China; Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China; University of Chinese Academy of Science, China.
Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China; University of Chinese Academy of Science, China.
Plant Sci. 2020 Mar;292:110353. doi: 10.1016/j.plantsci.2019.110353. Epub 2019 Nov 23.
The transcription factors EIN3 (ETHYLENE-INSENSITIVE 3) and EILs (EIN3-Likes) play important roles in plant development and defense responses; however, their mechanism in these processes remain unclear. Here, we report that OsEIL2, an EIN3-like transcription factor from rice (Oryza sativa), plays important roles in abiotic stress and leaf senescence. OsEIL2 is a nuclear-localized protein with transactivation activity in the C-terminus (amino acids 344-583) and can be induced by NaCl, polyethylene glycol (PEG), dark, and abscisic acid (ABA) treatment. Transgenic plants of overexpressing OsEIL2 (OsEIL2-OX) show reduced tolerance to salt and drought stress compared with the controls. While the transgenic plants of overexpressing OsEIL2-RNA interference (OsEIL2-RNAi) exhibit enhanced tolerance to salt and drought stress compared with the controls. Moreover, seedlings of OsEIL2-overexpressing transgenic plants exhibit delayed leaf development and an accelerated dark-induced senescence phenotype, whereas OsEIL2-RNAi plants display the opposite phenotype. We further found that OsEIL2 functions upstream of OsBURP14 and OsBURP16. OsBURP14 and OsBURP16 are the members of the β subunit of polygalacturonase subfamilies. OsBURP16 overexpression reduced pectin content and cell adhesion and increased abiotic stress sensitivity in rice. OsEIL2 binds directly to the promoter of OsBURP14 and OsBURP16 and activates their transcript levels. We also found that OsEIL2 overexpression decreased the pectin content by increasing polygalacturonase (PG) activity. Taken together, these results revealed a new mechanism of OsEIL2 in abiotic stress responses. These findings provide new insights into plant resistance to abiotic stress.
转录因子 EIN3（ETHYLENE-INSENSITIVE 3）和 EILs（EIN3-Likes）在植物发育和防御反应中发挥重要作用；然而，它们在这些过程中的机制仍不清楚。在这里，我们报告说，来自水稻（Oryza sativa）的 EIN3 样转录因子 OsEIL2 在非生物胁迫和叶片衰老中发挥重要作用。OsEIL2 是一种核定位蛋白，在 C 端（氨基酸 344-583）具有转录激活活性，并且可以被 NaCl、聚乙二醇（PEG）、黑暗和脱落酸（ABA）处理诱导。过表达 OsEIL2（OsEIL2-OX）的转基因植物与对照相比，对盐和干旱胁迫的耐受性降低。而过表达 OsEIL2 的转基因植物（OsEIL2-RNAi）与对照相比，对盐和干旱胁迫的耐受性增强。此外，过表达 OsEIL2 的转基因植物幼苗表现出叶片发育延迟和暗诱导衰老表型加速，而 OsEIL2-RNAi 植物则表现出相反的表型。我们进一步发现，OsEIL2 位于 OsBURP14 和 OsBURP16 的上游。OsBURP14 和 OsBURP16 是多聚半乳糖醛酸酶亚家族的β亚基成员。OsBURP16 的过表达降低了果胶含量和细胞黏附性，并增加了水稻的非生物胁迫敏感性。OsEIL2 直接结合到 OsBURP14 和 OsBURP16 的启动子上，并激活它们的转录水平。我们还发现，过表达 OsEIL2 通过增加多聚半乳糖醛酸酶（PG）活性降低了果胶含量。总之，这些结果揭示了 OsEIL2 在非生物胁迫反应中的一个新机制。这些发现为植物对非生物胁迫的抗性提供了新的见解。
