Isolation and structure elucidation of HT-toxin produced by Exserohilum turcicum

摘要

Northern corn leaf blight (NCLB), caused by Exserohilum turcicum (=Setosphaeria turcica), is a major corn disease in most corn-growing areas of the world and cause serious yield losses. Several enzymes and a heat-stable pathotoxin (HT-toxin), which is non-host selective, could be produced while E.turcicum was cultured in liquid medium in vitro. It had been reported that the toxin produced by E.turcicum grown in culture could be separated into two fractions, a chloroform and an aqueous extract, and could induce typical NCLB symptoms on corn. A substance called monocerin had been separated from E. turcicum culturing and a water-soluble compound that inhibits chlorophyll synthesis in corn plants had also been identified as a peptide. Major dominant genes conferring qualitative resistance and polygenic quantitative resistance were used to control the disease, and the toxin produced by E.turcicum was deduced to be a host-specific pathotoxin.