title: Inhibitory effect of selenium against Penicillium expansum and its possible mechanisms of action.
abstract: Some organic and inorganic salts could inhibit the growth of many pathogens. Selenium (Se), as an essential micronutrient, was effective in improving the plant resistance and antioxidant capacity at a low concentration. Penicillium expansum is one of the most important postharvest fungal pathogens, which can cause blue mold rot in various fruits and vegetables. In this study, the inhibitory effect of Se against P. expansum was evaluated. The result showed that Se strongly inhibited spore germination, germ tube elongation, and mycelial spread of P. expansum in the culture medium. The inhibitory effect was positively related to the concentration of Se used. Fluorescence microscopy observation of P. expansum conidia stained with propidium iodide (PI) indicated that the membrane integrity decreased to 37 % after the conidia were treated with Se (20 mg/l) for 9 h. With the use of an oxidant-sensitive probe 2,7-dichlorofluorescin (DCHF-DA), we found that Se at 15 mg/l could induce the generation of intracellular reactive oxygen species (ROS). Furthermore, methane dicarboxylic aldehyde (MDA) content, hydrogen peroxide (H2O2), and superoxide anion (O2 (-)) production rate in P. expansum spores exposed to Se increased markedly. Compared with the control, the activities of superoxide dismutase (SOD) and the content of glutathione (GSH) were reduced, confirming that damage of Se to cellular oxygen-eliminating system is the main reason. These results suggest that Se might serve as a potential alternative to synthetic fungicides for the control of the postharvest disease of fruit and vegetables caused by P. expansum.
authors.affiliation: Key Laboratory of Agri-Food Safety of Anhui Province, School of Plant Protection, Anhui Agricultural University, Hefei, 230036, China, 13732639644@163.com.
authors.forename: Zhi-Lin
authors.initials: ZL
authors.lastname: Wu
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Yin
authors.forename: Zhi-Qing
authors.initials: ZQ
authors.lastname: Lin
authors.forename: Gary S
authors.initials: GS
authors.lastname: Bañuelos
authors.forename: Lin-Xi
authors.initials: LX
authors.lastname: Yuan
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Miao
authors.initials: M
authors.lastname: Li
mesh_terms: D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D008856:Microscopy, Fluorescence; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development; D010407:Penicillium / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development* / Q000502:physiology; D011419:Propidium / Q000032:analysis; D017382:Reactive Oxygen Species / Q000032:analysis; D012643:Selenium / Q000633:toxicity*; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013194:Staining and Labeling
chemical_list: D017382:Reactive Oxygen Species; D011419:Propidium; D012643:Selenium