title: The natural product citral can cause significant damage to the hyphal cell walls of Magnaporthe grisea.
abstract: In order to find a natural alternative to the synthetic fungicides currently used against the devastating rice blast fungus, Magnaporthe grisea, this study explored the antifungal potential of citral and its mechanism of action. It was found that citral not only inhibited hyphal growth of M. grisea, but also caused a series of marked hyphal morphological and structural alterations. Specifically, citral was tested for antifungal activity against M. grisea in vitro and was found to significantly inhibit colony development and mycelial growth with IC50 and IC90 values of 40.71 and 203.75 μg/mL, respectively. Furthermore, citral reduced spore germination and germ tube length in a concentration-dependent manner. Following exposure to citral, the hyphal cell surface became wrinkled with folds and cell breakage that were observed under scanning electron microscopy (SEM). There was damage to hyphal cell walls and membrane structures, loss of villous-like material outside of the cell wall, thinning of the cell wall, and discontinuities formed in the cell membrane following treatment based on transmission electron microscopy (TEM). This increase in chitinase activity both supports the morphological changes seen in the hyphae, and also suggests a mechanism of action. In conclusion, citral has strong antifungal properties, and treatment with this compound is capable of causing significant damage to the hyphal cell walls of M. grisea.
authors.affiliation: Institute of Crop Protection, Guizhou University, Guiyang 550025, China.
authors.forename: Rong-Yu
authors.initials: RY
authors.lastname: Li
authors.affiliation: Institute of Crop Protection, Guizhou University, Guiyang 550025, China.
authors.forename: Xiao-Mao
authors.initials: XM
authors.lastname: Wu
authors.affiliation: Institute of Crop Protection, Guizhou University, Guiyang 550025, China.
authors.forename: Xian-Hui
authors.initials: XH
authors.lastname: Yin
authors.affiliation: Instrument Center of Institute of Microbiology Chinese Academy of Sciences, Institute of Microbiology, Chinese Academy of Science, Beijing 100101, China.
authors.forename: Jing-Nan
authors.initials: JN
authors.lastname: Liang
authors.affiliation: Institute of Crop Protection, Guizhou University, Guiyang 550025, China. lm21959@163.com.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D000080462:Acyclic Monoterpenes; D001688:Biological Products / Q000494:pharmacology*; D002473:Cell Wall / Q000187:drug effects*; D002688:Chitinases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020536:Enzyme Activators / Q000494:pharmacology; D005659:Fungicides, Industrial / Q000494:pharmacology*; D025301:Hyphae / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D020082:Magnaporthe / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D050296:Microbial Viability / Q000187:drug effects; D039821:Monoterpenes / Q000494:pharmacology*
chemical_list: D000080462:Acyclic Monoterpenes; D001688:Biological Products; D020536:Enzyme Activators; D005659:Fungicides, Industrial; D039821:Monoterpenes; D002688:Chitinases; C007076:citral