Detoxification of the cruciferous phytoalexin brassinin in Sclerotinia sclerotiorum requires an inducible glucosyltransferase.
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.
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. s.pedras@usask.ca
M Soledade C
MS
Pedras
Pearson W K
PW
Ahiahonu
Mohammad
M
Hossain
D000935:Antifungal Agents / Q000378:metabolism* / Q000633:toxicity; D001203:Ascomycota / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002457:Cell Extracts; D002851:Chromatography, High Pressure Liquid; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D008658:Inactivation, Metabolic; D007211:Indoles / Q000378:metabolism* / Q000633:toxicity; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010936:Plant Extracts / Q000378:metabolism* / Q000633:toxicity; D012717:Sesquiterpenes; D013729:Terpenes; D013859:Thiocarbamates / Q000378:metabolism* / Q000633:toxicity; D000094162:Phytoalexins
D000935:Antifungal Agents; D002457:Cell Extracts; D007211:Indoles; D010936:Plant Extracts; D012717:Sesquiterpenes; D013729:Terpenes; D013859:Thiocarbamates; C089020:brassinin; D005964:Glucosyltransferases; D000094162:Phytoalexins