Production of extracellular hydrolytic enzymes by the grapevine dieback fungus Eutypa lata

Production of extracellular cellulase, xylanase, 1,3-beta-glucanase, chitin ase and protease was demonstrated in the grapevine dieback fungus Eutypa la ta growing in vitro and on autoclaved wood. Enzyme production in vitro depe nded largely on the culture medium. In grape wood extract medium, xylanase was the dominating enzyme whereas protease activity prevailed in potato dex trose broth. In annual grape wood, activities of cellulase, xylanase and pr otease activity were nearly equally high; low levels of 1,3-beta-glucanase were measurable. In perennial wood, proc-ease was clearly the dominating en zyme, followed by chitinase. Their activity was highly correlated with visi ble mycelial growth. 1,3-beta-glucanase activity was not detectable in pere nnial wood. Six different Eutypa lata isolates showed a nearly identical pa ttern of extracellular enzyme activities in perennial wood. Enzyme detection in xylem washing fluid (XWF) was up to 35-fold more sensit ive than in wood extracts. The data concerning cellulase give rise to assum e the existence of two isoforms with different: pH- and temperature optima and different substrate-binding properties.