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Endogenous ABA alleviates rice ammonium toxicity by reducing ROS and free ammonium via regulation of the SAPK9–bZIP20 pathway
- Source :
- Journal of Experimental Botany
- Publication Year :
- 2020
- Publisher :
- Oxford University Press (OUP), 2020.
-
Abstract
- Abscisic acid plays a positive role in regulating the OsSAPK9–OsbZIP20 pathway and elevating antioxidant and GS/GOGAT activities in rice to increase tolerance to high-NH4+ stress.<br />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.
- Subjects :
- inorganic chemicals
Antioxidant
Physiology
medicine.medical_treatment
OsbZIP20
Mutant
antioxidant activity
Plant Science
medicine.disease_cause
chemistry.chemical_compound
Glutamate-Ammonia Ligase
Glutamine synthetase
Ammonium Compounds
medicine
ammonium assimilation
Ammonium
Abscisic acid
chemistry.chemical_classification
Reactive oxygen species
Oryza sativa
AcademicSubjects/SCI01210
fungi
food and beverages
high ammonium stress
Oryza
Research Papers
OsSAPK9
ABA
chemistry
Biochemistry
Reactive Oxygen Species
Oxidative stress
Abscisic Acid
Subjects
Details
- ISSN :
- 14602431 and 00220957
- Volume :
- 71
- Database :
- OpenAIRE
- Journal :
- Journal of Experimental Botany
- Accession number :
- edsair.doi.dedup.....fd6cfd230e78de51899c759290b95b90