HC-toxin

HC-toxin is a virulence factor for the plant pathogenic fungus Cochliobolus (Helminthosporium) carbonum. Specific resistance to HC-toxin and C. carbonum is controlled by Mendelian genes in maize that encode carbonyl reductases, which detoxify HC-toxin by reducing the carbonyl group of Aeo. Analogs of HC-toxin are made by at least five other fungi. Biosynthesis of HC-toxin involves at least five genes that are present in two or three functional copies over a ∼500 kb region. The genes are absent from natural toxin non-producing isolates of C. carbonum. HC-toxin is a universal inhibitor of histone deacetylases of the Rpd3/Hda1 class.