Furukawa Tomohiro, Yoshinari Tomoya, Sakuda Shohei
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
National Institute of Health Sciences, 1-18-1 Kamiyouga, Setagaya-ku, Tokyo 158-0098, Japan.
FEMS Microbiol Lett. 2017 Nov 15;364(21). doi: 10.1093/femsle/fnx213.
The intracellular superoxide level is a clue to clarification of the regulatory mechanism for mycotoxin production in Fusarium graminearum. In this study, we focused on two manganese superoxide dismutases (SODs) of the fungus, FgSOD2 and FgSOD3, to investigate the relationship of the superoxide level to trichothecene production. Recombinant FgSOD2 and FgSOD3 showed SOD activity, and they were localized mainly in the mitochondria and cytoplasm, respectively. Trichothecene production and mRNA levels of Tri5 and Tri6, which encode a trichothecene biosynthetic enzyme and a key regulator of trichothecene production, respectively, were greatly reduced in gene-deletion mutants of FgSod2 and FgSod3 (ΔFgSod2 and ΔFgSod3). Significant increases in the cytosolic and mitochondrial superoxide levels were observed in ΔFgSod2 and ΔFgSod3, respectively. These results suggested that the cellular superoxide level affects trichothecene production in F. graminearum.
细胞内超氧化物水平是阐明禾谷镰刀菌中霉菌毒素产生调控机制的一个线索。在本研究中，我们聚焦于该真菌的两种锰超氧化物歧化酶（SOD），即FgSOD2和FgSOD3，以研究超氧化物水平与单端孢霉烯族毒素产生之间的关系。重组FgSOD2和FgSOD3表现出SOD活性，且它们分别主要定位于线粒体和细胞质中。在FgSod2和FgSod3的基因缺失突变体（ΔFgSod2和ΔFgSod3）中，单端孢霉烯族毒素的产生以及分别编码单端孢霉烯族毒素生物合成酶和单端孢霉烯族毒素产生关键调节因子的Tri5和Tri6的mRNA水平大幅降低。在ΔFgSod2和ΔFgSod3中，分别观察到胞质和线粒体超氧化物水平显著升高。这些结果表明，细胞内超氧化物水平影响禾谷镰刀菌中单端孢霉烯族毒素的产生。
