title: Nox gene expression and cytochemical localization of hydrogen peroxide in Polyporus umbellatus sclerotial formation.
abstract: The effect of temperature shift on Polyporus umbellatus sclerotial development was investigated. Micromorphology of the sclerotia was observed by using scanning electron microscopy (SEM). The cytochemical localization of H2O2 expressed as CeCl3 deposition at the subcellular level was observed by using transmission electron microscopy (TEM). Nox gene expression in sclerotia and mycelia was detected by quantitative real-time PCR (qRT-PCR) analysis. In addition, superoxide dismutase (SOD) and catalase (CAT) specific activities increased during sclerotial development and decreased after the antioxidant diphenyleneiodonium (DPI) was used. Results indicated that the temperature shift treatment induced P. umbellatus sclerotial formation. Compared with the mycelia, the Nox gene was respectively upregulated by 10.577-, 30.984- and 25.469-fold in the sclerotia of SI, SD and SM stages respectively. During the sclerotial formation, H2O2 accumulation was observed in the cell walls or around the organelle membranes of the mycelial cells. The antioxidant DPI decreased the generation of H2O2 in mycelial cells. The specific activity of SOD and CAT levels was decreased significantly by DPI. The activity of the two antioxidant enzymes in the mycelia increased much more during sclerotial formation (p < 0.05). Oxidative stress was closely associated with sclerotial development in P. umbellatus induced by temperature shift treatment.
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Malianwa North Road 151, Haidian District, Beijing 100193, China. sxguo1986@163.com.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Xing
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Chao
authors.initials: C
authors.lastname: Song
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Liu
authors.forename: Shun-Xing
authors.initials: SX
authors.lastname: Guo
authors.forename: Chun-Lan
authors.initials: CL
authors.lastname: Wang
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D002374:Catalase / Q000096:biosynthesis; D015966:Gene Expression Regulation, Fungal; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008854:Microscopy, Electron; D025282:Mycelium / Q000201:enzymology / Q000254:growth & development; D019255:NADPH Oxidases / Q000096:biosynthesis / Q000235:genetics*; D009861:Onium Compounds / Q000494:pharmacology; D018384:Oxidative Stress; D055492:Polyporus / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure*; D013482:Superoxide Dismutase / Q000096:biosynthesis; D013696:Temperature
chemical_list: D000975:Antioxidants; D009861:Onium Compounds; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases