Cornexistin: A new fungal metabolite with herbicidal activity.

Abstract

Cornexistint, a new compound demonstrating promising herbicidal activity, was purified from the culture nitrate of a newly-isolated fungus identified as Paecilomyces variotii SANK 21086. The compoundwas extracted with organic solvents from the culture nitrate, purified using column chromatography on Sephadex LH-20 and finally crystallized from methylene chloride. Following analysis of its physico-chemical properties it was identified to be a new compound belonging to the nonadride group. Chemical structure elucidation was conducted by analyses of various spectral data and the structure was finally confirmed by means of X-ray crystallographic analysis. Based on its herbicidal characteristics cornexistin may be classified as a postemergence herbicide active against certain young annual and perennial monocotyledonous and dicotyledonous plants with selective protection for corn.

Natural Compounds as Next-Generation Herbicides

“…This enzyme catalyzes the reversible transfer of an a-amino group interconverting Asp and a-ketoglutarate to oxaloacetate and Glu. A number of phytotoxic natural products such as gostatin (5-amino-2-carboxy-4-oxo-1,4,5,6-tetrahydro-pyridine-3-acetic acid), produced by S. sumanensis (Nishino et al, 1984), and cornexistin, produced by P. variotii (Nakajima et al, 1991;Amagasa et al, 1994), target this enzyme. Gostatin is a slow-binding inhibitor (time dependent) that acts as a suicide substrate (mechanism-based inhibitor).…”

Agroactive Compounds of Microbial Origin

“…Thus, cornexistin is probably useful for postemergence weed control in corn fields. A weak herbicidal effect of the structurally related rubratoxin B was reported earlier (94).…”

“…Deoxy dt�rivatives were synthesized but showed no activity (82). Cornexistin is a lipophilic herbicidal metabolite with a nonadride structure (Figure 3) isolated from Paecilomyces variotii SANK 21086 (94). Pot tests demonstrated activity against common annual species of weeds on postemerg ence treatment at 100 and 500 ppm.…”

Avaliação da capacidade de produzir fitotoxinas in vitro por parte de fungos com propriedades antagônicas a nematóides

“…(STONARD & MILLER-WIDEMAN, 1994), Fusarium spp. (ABBAS et al, 1995(ABBAS et al, , 1998SVABOVA & LEBEDA, 2005;VESONDER et al, 2000), Paecilomyces vatiotii Bainer (NAKAJIMA et al, 1991), Penicillium spp. (STONARD & MILLER-WIDEMAN, 1994), Sclerotinia sclerotiorum (Lib.)…”