Induction of chlorosis, ROs generation and cell death by a toxin isolated from Pyricularia oryzae.
The ethyl acetate extract of the conidia germination fluid from an Avena isolate (Br58) of Pyricularia oryzae had chlorosis-inducing activity on oat leaf segments. The same activity was also present in the acetone extract of an oatmeal agar culture of Br58. Fungal cultures were used for a large-scale preparation. A series of acetone and ethyl acetate extraction monitored by chromatography was used to isolate an active fraction. The active principle was purified by HPLC. We show by NMR and LC/MS that the toxin was an oxidized C18 unsaturated fatty acid named Mag-toxin. Mag-toxin induced chlorosis on oat leaf segments incubated in the light but not in the dark. Reactive oxygen species (ROS) and cell death were induced by Mag-toxin in oat cells. The sub-cellular localization of ROS generation induced by the toxin treatment was correlated with the location of mitochondria. Interestingly, the induction of ROS generation and cell death by Mag-toxin was light-independent.
Faculty of Business, Hannan University, Matsubara, Japan. tsuru@hannan-u.ac.jp
Tetsu
T
Tsurushima
Yukari
Y
Minami
Hisashi
H
Miyagawa
Hitoshi
H
Nakayashiki
Yukio
Y
Tosa
Shigeyuki
S
Mayama
D018554:Avena / Q000382:microbiology; D016923:Cell Death / Q000187:drug effects* / Q000528:radiation effects; D002734:Chlorophyll; D002851:Chromatography, High Pressure Liquid; D005231:Fatty Acids, Unsaturated; D008027:Light; D020082:Magnaporthe / Q000737:chemistry*; D009183:Mycotoxins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012275:Oryza / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000528:radiation effects
D005231:Fatty Acids, Unsaturated; D009183:Mycotoxins; D017382:Reactive Oxygen Species; D002734:Chlorophyll