Pedras M Soledade C, Ahiahonu Pearson W K, Hossain Mohammad
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
Phytochemistry. 2004 Oct;65(19):2685-94. doi: 10.1016/j.phytochem.2004.08.033.
The phytoalexins, brassinin, 1-methoxybrassinin and cyclobrassinin, were metabolized by the stem rot fungus Sclerotinia sclerotiorum into their corresponding glucosyl derivatives displaying no detectable antifungal activity. Importantly, co-incubation of S. sclerotiorum with camalexins, various phytoalexin analogs, and brassinin indicated that a synthetic camalexin derivative could slow down substantially the rate of brassinin detoxification. Furthermore, inducible brassinin glucosyltransferase (BGT) activity was detected in crude cell-free extracts of S. sclerotiorum. BGT activity was induced by the phytoalexin camalexin, and the brassinin analogs methyl tryptamine dithiocarbamate and methyl 1-methyltryptamine dithiocarbamate. The overall results suggest that the fungus S. sclerotiorum in its continuous adaptation and co-evolution with brassinin producing plants, has acquired efficient glucosyltransferase(s) that can disarm some of the most active plant chemical defenses.
植保素、油菜素、1-甲氧基油菜素和环油菜素被菌核病菌代谢为相应的葡萄糖基衍生物，这些衍生物没有可检测到的抗真菌活性。重要的是，将菌核病菌与camalexins、各种植保素类似物和油菜素共同培养表明，一种合成的camalexin衍生物可以显著减缓油菜素解毒的速度。此外，在菌核病菌的无细胞粗提物中检测到了可诱导的油菜素葡萄糖基转移酶（BGT）活性。BGT活性由植保素camalexin以及油菜素类似物甲基色胺二硫代氨基甲酸盐和甲基1-甲基色胺二硫代氨基甲酸盐诱导。总体结果表明，菌核病菌在与产生油菜素的植物持续适应和共同进化过程中，获得了能够解除一些最活跃的植物化学防御的高效葡萄糖基转移酶。
