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Biological Control of the Grapevine Dieback Fungus Eutypa lata I: Screening of Bacterial Antagonists
Author(s) -
Schmidt C. S.,
Lorenz D.,
Wolf G. A.
Publication year - 2001
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.2001.tb03874.x
Subject(s) - biology , bacillus subtilis , mycelium , microbiology and biotechnology , chitinase , antagonism , pseudomonas , bacteria , fungus , bacillales , serratia marcescens , botany , escherichia coli , enzyme , biochemistry , genetics , receptor , gene
Antifungal bacterial strains were assayed for antagonistic activity towards the grapevine dieback fungus Eutypa lata in vitro and on grape wood. One hundred and twenty‐one of 188 isolates (64%) exhibited antagonistic activity towards E. lata in vitro (> 83% of the tested actinomycetes, Bacillus and Erwinia herbicola strains and 32% of the Pseudomonas strains). On autoclaved grape wood discs, liquid cultures from 24 of 76 selected bacterial strains (32%) caused at least 50% suppression of mycelial growth over a period of 2 weeks. Among these were two Bacillus subtilis , four E. herbicola , two Serratia plymuthica and 16 actinomycete isolates. One B. subtilis strain (B1α), two E. herbicola strains (JII/E2 and JII/E4) and one actinomycete (A123) showed the highest degree of antagonism (70‐100% control over a period of 4 weeks). In E. herbicola and the actinomycete A123 the cell‐free supernatant was the active fraction of the applied liquid culture (100% control); suspended cells showed no or limited effect. Conversely, in B. subtilis the cells were the decisive component (50‐70% control). Erwinia herbicola JII/E2 and B. subtilis B1α inhibited growth of six different E. lata isolates on wood significantly. The strong antagonistic effect of the four bacterial strains was confirmed by the measurement of fungal hydrolase activity (chitinase, protease, cellulase). Activities of fungal hydrolases were highly correlated with mycelial growth on wood ( r > 0.88). In B. subtilis B1α antagonistic activity and ability to colonize grape wood was further demonstrated by cryo‐scanning electron microscopy.