著者

Takumi Nishiuchi Makoto Kimura Kazuhiro Sato

出版者

日本マイコトキシン学会

雑誌

マイコトキシン (ISSN:02851466)

巻号頁・発行日

vol.65, no.2, pp.143-147, 2015-07-31 (Released:2015-09-01)

参考文献数

16

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Phytopathogenic fungi Fusarium species are etiological agents of Fusarium head blight (FHB) and produce trichothecene mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV) in cereals especially barley and wheat. Trichothecenes inhibit the protein synthesis in eukaryotic ribosomes. Therefore, trichothecene-contaminated cereals often cause foodborne illness such as immunosuprression, vomiting, and diarrhea in human and livestocks. Trichothecenes are also phytotoxins and act as effectors to promote infection in host plants. Based on visible disease symptoms, we selected 15 FHB-resistant lines of barley. When these resistant lines and susceptible controls were inoculated with conidia of F. asiaticum, the mycotoxin (NIV) contaminations of resistant two lines were less than half of those of susceptible controls. Furthermore, we performed comparative analysis of global gene expression profiles between these FHB-resistant (low NIV accumulation) lines vs. susceptible controls. A number of genes including the glutathione S-transferase (HvGST13) and glutathione reductase (HvGR2) were specifically up-regulated in the FHB-resistant lines. It is likely that these two genes are involved in the detoxification of NIV by NIV-GSH conjugation in barley. Therefore, we are studying these genes as candidates of trichothecene-detoxifing genes. This study may contributes to the understanding molecular mechanism of trichothecene detoxification in cereals.

著者

Makoto KIMURA Takeshi TOKAI Naoko TAKAHASHI-ANDO Shuichi OHSATO Makoto FUJIMURA

出版者

(社)日本農芸化学会

雑誌

Bioscience, Biotechnology, and Biochemistry (ISSN:09168451)

巻号頁・発行日

vol.71, no.9, pp.2105-2123, 2007-09-23 (Released:2007-09-23)

参考文献数

120

被引用文献数

334

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Trichothecenes are a large family of sesquiterpenoid secondary metabolites of Fusarium species (e.g., F. graminearum) and other molds. They are major mycotoxins that can cause serious problems when consumed via contaminated cereal grains. In the past 20 years, an outline of the trichothecene biosynthetic pathway has been established based on the results of precursor feeding experiments and blocked mutant analyses. Following the isolation of the pathway gene Tri5 encoding the first committed enzyme trichodiene synthase, 10 biosynthesis genes (Tri genes; two regulatory genes, seven pathway genes, and one transporter gene) were functionally identified in the Tri5 gene cluster. At least three pathway genes, Tri101 (separated alone), and Tri1 and Tri16 (located in the Tri1-Tri16 two-gene cluster), were found outside of the Tri5 gene cluster. In this review, we summarize the current understanding of the pathways of biosynthesis, the functions of cloned Tri genes, and the evolution of Tri genes, focusing on Fusarium species.