title: Involvement of alternative oxidase in the regulation of growth, development, and resistance to oxidative stress of Sclerotinia sclerotiorum.
abstract: Sclerotinia sclerotiorum is a cosmopolitan, filamentous, fungal pathogen that can cause serious disease in many kinds of crops. Alternative oxidase is the terminal oxidase of the alternative mitochondrial respiratory pathway in fungi and higher plants. We report the presence of this alternative pathway respiration and demonstrate its expression in two isolates of S. sclerotiorum under unstressed, normal culture conditions. Application of salicylhydroxamic acid, a specific inhibitor of alternative oxidase, severely inhibited the mycelial growth of S. sclerotiorum both on potato dextrose agar plates and in liquid culture media. Inhibition of alternative oxidase could influence the growth pattern of S. sclerotiorum, as salicylhydroxamic acid treatment induced obvious aerial mycelia growing on potato dextrose agar plates. Under the treatment with salicylhydroxamic acid, S. sclerotiorum formed sclerotia much more slowly than the control. Treatment with hydrogen peroxide in millimolar concentrations greatly decreased the growth rate of mycelia and delayed the formation of sclerotia in both tested S. sclerotiorum isolates. As well, this treatment obviously increased their alternative pathway respiration and the levels of both mRNA and protein of the alternative oxidase. These results indicate that alternative oxidase is involved in the regulation of growth, development, and resistance to oxidative stress of S. sclerotiorum.
authors.affiliation: Institute of Biotechnology, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, P. R. China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xu
authors.forename: Fei
authors.initials: F
authors.lastname: Yao
authors.forename: Wu-Sheng
authors.initials: WS
authors.lastname: Liang
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Li
authors.forename: Dian-Rong
authors.initials: DR
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Zheng-Yi
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D001203:Ascomycota / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology*; D003470:Culture Media / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000633:toxicity; D025301:Hyphae / Q000187:drug effects / Q000254:growth & development; D024101:Mitochondrial Proteins / Q000378:metabolism*; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D012457:Salicylamides / Q000378:metabolism; D013312:Stress, Physiological; D000099188:Alternative Oxidase
chemical_list: D003470:Culture Media; D004791:Enzyme Inhibitors; D006861:Hydrogen Peroxide; D024101:Mitochondrial Proteins; D016877:Oxidants; D010088:Oxidoreductases; D010940:Plant Proteins; D012457:Salicylamides; D000099188:Alternative Oxidase; C005703:salicylhydroxamic acid