Endogenous ABA alleviates rice ammonium toxicity by reducing ROS and free ammonium via regulation of the SAPK9-bZIP20 pathway.

Autor:	Sun L; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu, China.; State Key Lab of Crop Genetics and Germplasm Enhancement, Cytogenetics Institute, Nanjing Agricultural University/JCIC-MCP, Nanjing, Jiangsu, China., Di DW; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu, China., Li G; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu, China., Kronzucker HJ; School of Agriculture and Food, University of Melbourne, Parkville, VIC, Australia.; Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada., Wu X; Key Lab of Plant-Soil Interaction, MOE, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China., Shi W; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu, China.
Jazyk:	angličtina
Zdroj:	Journal of experimental botany [J Exp Bot] 2020 Jul 25; Vol. 71 (15), pp. 4562-4577.
DOI:	10.1093/jxb/eraa076
Abstrakt:	Ammonium (NH4+) is one of the principal nitrogen (N) sources in soils, but is typically toxic already at intermediate concentrations. The phytohormone abscisic acid (ABA) plays a pivotal role in responses to environmental stresses. However, the role of ABA under high-NH4+ stress in rice (Oryza sativa L.) is only marginally understood. Here, we report that elevated NH4+ can significantly accelerate tissue ABA accumulation. Mutants with high (Osaba8ox) and low levels of ABA (Osphs3-1) exhibit elevated tolerance or sensitivity to high-NH4+ stress, respectively. Furthermore, ABA can decrease NH4+-induced oxidative damage and tissue NH4+ accumulation by enhancing antioxidant and glutamine synthetase (GS)/glutamate synthetasae (GOGAT) enzyme activities. Using RNA sequencing and quantitative real-time PCR approaches, we ascertain that two genes, OsSAPK9 and OsbZIP20, are induced both by high NH4+ and by ABA. Our data indicate that OsSAPK9 interacts with OsbZIP20, and can phosphorylate OsbZIP20 and activate its function. When OsSAPK9 or OsbZIP20 are knocked out in rice, ABA-mediated antioxidant and GS/GOGAT activity enhancement under high-NH4+ stress disappear, and the two mutants are more sensitive to high-NH4+ stress compared with their wild types. Taken together, our results suggest that ABA plays a positive role in regulating the OsSAPK9-OsbZIP20 pathway in rice to increase tolerance to high-NH4+ stress. (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu