Metabolism of the host-selective toxins destruxin B and homodestruxin B: Probing a plant disease resistance trait

[GRAPHICS] Metabolism of the host-selective toxins destruxin B (1) and homodestruxin B (2) by plants resistant and susceptible to Alternaria blackspot (caused by the fungal pathogen Alternaria brassicae (Berk,) Sacc,) was established us ing synthetic radiolabeied compounds. The toxins are transformed into the l ess phytotoxic hydroxydestruxins 3 and 4. The rate of metabolic transformat ion was correlated with the plant's disease resistance, i.e., significantly faster rates were observed for plants resistant to the pathogen, Efficient syntheses of 1, 2, 3, and 4 are described.