AB5046A AND B, NOVEL CHLOROSIS-INDUCING SUBSTANCES FROM NODULISPORIUMSP

Novel chlorosis-inducing substances, AB5046A and B, were isolated from the culture broth of a fungal strain. The producing organism, designa ted AB5046, was identified as a member of Nodulisporium. AB5046A and B were purified by extraction with EtOAc and silica gel chromatography. The structure of AB5046A and B were determined to be 2-butyryl-3,5-di hydroxy-cyclohex-2-ene-l-one and 2-acetyl-3,5-dihydroxy-cyclohex-2-ene -1-one respectively, by spectroscopic analyses. AB5046A and B induced chlorosis against Japanese barnyard millet in vitro. The chlorosis act ivity of these compounds was stronger against monocotyledons than dico tyledons.