Fusarium phytotoxin trichothecenes have an elicitor-like activity in Arabidopsis thaliana, but the activity differed significantly among their molecular species.
Phytopathogenic fungi such as Fusarium spp. synthesize trichothecene family phytotoxins. Although the type B trichothecene, deoxynivalenol (DON), is thought to be a virulence factor allowing infection of plants by their trichothecene-producing Fusarium spp., little is known about effects of trichothecenes on the defense response in host plants. Therefore, in this article, we investigated these effects of various trichothecenes in Fusarium-susceptible Arabidopsis thaliana. Necrotic lesions were observed in Arabidopsis leaves infiltrated by 1 microM type A trichothecenes such as T-2 toxin. Trichothecene-induced lesions exhibited dead cells, callose deposition, generation of hydrogen peroxide, and accumulation of salicylic acids. Moreover, infiltration by trichothecenes caused rapid and prolonged activation of two mitogen-activated protein kinases and induced expression of both PR-1 and PDF1.2 genes. Thus, type A trichothecenes trigger the cell death by activation of an elicitor-like signaling pathway in Arabidopsis. Although DON did not have such an activity even at 10 microM, translational inhibition by DON was observed at concentrations above 5 microM. These results suggested that DON is capable of inhibiting translation in Arabidopsis cells without induction of the elicitor-like signaling pathway.
Nishiuchi
Takumi
T
Division of Functional Genomics, Advanced Science Research Center, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934, Japan. tnish9@kenroku.kanazawa-u.ac.jp
Masuda
Daisuke
D
Nakashita
Hideo
H
Ichimura
Kazuya
K
Shinozaki
Kazuo
K
Yoshida
Shigeo
S
Kimura
Makoto
M
Yamaguchi
Isamu
I
Yamaguchi
Kazuo
K