title: The alternative respiratory pathway is involved in brassinosteroid-induced environmental stress tolerance in Nicotiana benthamiana.
abstract: Brassinosteroids (BRs), plant steroid hormones, play essential roles in modulating cell elongation, vascular differentiation, senescence, and stress responses. However, the mechanisms by which BRs regulate plant mitochondria and resistance to abiotic stress remain largely unclear. Mitochondrial alternative oxidase (AOX) is involved in the plant response to a variety of environmental stresses. In this report, the role of AOX in BR-induced tolerance against cold, polyethylene glycol (PEG), and high-light stresses was investigated. Exogenous applied brassinolide (BL, the most active BR) induced, while brassinazole (BRZ, a BR biosynthesis inhibitor) reduced alternative respiration and AOX1 expression in Nicotiana benthamiana. Chemical scavenging of H2O2 and virus-induced gene silencing (VIGS) of NbRBOHB compromised the BR-induced alternative respiratory pathway, and this result was further confirmed by NbAOX1 promoter analysis. Furthermore, inhibition of AOX activity by chemical treatment or a VIGS-based approach decreased plant resistance to environmental stresses and compromised BR-induced stress tolerance. Taken together, our results indicate that BR-induced AOX capability might contribute to the avoidance of superfluous reactive oxygen species accumulation and the protection of photosystems under stress conditions in N. benthamiana.
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, PR China.
authors.forename: Xing-Guang
authors.initials: XG
authors.lastname: Deng
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China hhlin@scu.edu.cn yuanmiao1892@163.com.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Zhang
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China hhlin@scu.edu.cn yuanmiao1892@163.com.
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Lin
mesh_terms: D060406:Brassinosteroids / Q000494:pharmacology*; D003080:Cold Temperature; D008027:Light; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013260:Steroids, Heterocyclic / Q000494:pharmacology*; D013312:Stress, Physiological; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014230:Triazoles / Q000494:pharmacology; D000099188:Alternative Oxidase
chemical_list: D060406:Brassinosteroids; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011092:Polyethylene Glycols; D017382:Reactive Oxygen Species; D013260:Steroids, Heterocyclic; D014230:Triazoles; D000099188:Alternative Oxidase; C412342:brassinazole; C023623:brassinolide
keywords: Alternative oxidase; Nicotiana benthamiana; brassinosteroids; reactive oxygen species; stress tolerance.