IDENTIFICATION OF MYCELIAL POLYPEPTIDES ASSOCIATED WITH GLIOTOXIN-PRODUCING STRAINS OF THE BIOCONTROL FUNGUS GLIOCLADIUM-VIRENS

Soluble mycelial polypeptides from two gliotoxin-producing strains of Gliocladium virens (G-20 and G-15) were compared with the soluble mycelial polypeptides from two strains unable to produce gliotoxin (G-3 and G-4) by using two-dimensional gel electrophoresis. In single comparisons, there were between 146 and 170 polypeptides that were common to both producers and nonproducers, and between 12 and 14 polypeptides that were uniquely associated with producers of gliotoxin. However, when the data from all experiments were compared, there were four major polypeptides that were consistently and uniquely associated with strains that have the ability to produce gliotoxin. Molecular weights (kDa) and isoelectric points (pI) of these four polypeptides were estimated to be 33.8, 7.35; 33.8, 7.10; 27.2, 7.25; and 15.1, 4.6. In addition, there were several polypeptides that were consistently more abundant in gliotoxin-producing strains. The results may help to explain physiological differences that affect gliotoxin production and lead to improved methods for selecting and formulating G. virens for biological control.