TY - JOUR
T1 - Growth of chitinolytic dune soil ß-subclass Proteobacteria in response to invading fungal hyphae
AU - De Boer, W.
AU - Klein Gunnewiek, P.J.A.
AU - Kowalchuk, G.A.
AU - Van Veen, J.A.
N1 - Reporting year: 2001
Metis note: 2810; CTE; TME ; ME file:///L:/Endnotedatabases/NIOOPUB/pdfs/Pdfs2001/DeBoer_ea_2810.pdf
PY - 2001
Y1 - 2001
N2 - It has frequently been reported that chitinolytic soil bacteria, in particular biocontrol strains, can lyse living fungal hyphae, thereby releasing potential growth substrate. However, the conditions used in such assays (high bacterial density, rich media, fragmented hyphae) make it difficult to determine whether mycolytic activity is actually of importance for the growth and survival of chitinolytic bacteria in soils. An unidentified group of beta -subclass Proteobacteria (C beta Ps) was most dominant among the culturable nonfilamentous chitinolytic bacteria isolated from Dutch sand dune soils. Here we demonstrate that the CpPs grew at the expense of extending fungal mycelium of three dune soil fungi (Chaetomium globosum, Fusarium culmorum, and Mucor hiemalis) under nutrient-limiting, soil-like conditions. Aggregates of C beta Ps were also often found attached to fungal hyphae. The growth of a control group of dominant nonchitinolytic dune soil bacteria (beta- and gamma -subclass Proteobacteria) was not stimulated in the mycelial zone, indicating that growth-supporting materials were not independently released in appreciable amounts by the extending hyphae. Therefore, mycolytic activities of C beta Ps have apparently been involved in allowing them to grow after exposure to living hyphae. The chitinase inhibitor allosamidin did not, in the case of Mucor, or only partially, in the cases of Chaetomium and Fusarium, repress mycolytic growth of the CpPs, indicating that chitinase activity alone could not explain the extent of bacterial proliferation. Chitinolytic Stenotrophomonas-like and Cytophaga-like bacteria, isolated from the same dune soils, were only slightly stimulated by exposure to fungal hyphae. [KEYWORDS: Biological-control; serratia-marcescens; ammophila-arenaria; plant-pathogens; borne fungi; chitinase; bacteria; maltophilia; allosamidin; strain]
AB - It has frequently been reported that chitinolytic soil bacteria, in particular biocontrol strains, can lyse living fungal hyphae, thereby releasing potential growth substrate. However, the conditions used in such assays (high bacterial density, rich media, fragmented hyphae) make it difficult to determine whether mycolytic activity is actually of importance for the growth and survival of chitinolytic bacteria in soils. An unidentified group of beta -subclass Proteobacteria (C beta Ps) was most dominant among the culturable nonfilamentous chitinolytic bacteria isolated from Dutch sand dune soils. Here we demonstrate that the CpPs grew at the expense of extending fungal mycelium of three dune soil fungi (Chaetomium globosum, Fusarium culmorum, and Mucor hiemalis) under nutrient-limiting, soil-like conditions. Aggregates of C beta Ps were also often found attached to fungal hyphae. The growth of a control group of dominant nonchitinolytic dune soil bacteria (beta- and gamma -subclass Proteobacteria) was not stimulated in the mycelial zone, indicating that growth-supporting materials were not independently released in appreciable amounts by the extending hyphae. Therefore, mycolytic activities of C beta Ps have apparently been involved in allowing them to grow after exposure to living hyphae. The chitinase inhibitor allosamidin did not, in the case of Mucor, or only partially, in the cases of Chaetomium and Fusarium, repress mycolytic growth of the CpPs, indicating that chitinase activity alone could not explain the extent of bacterial proliferation. Chitinolytic Stenotrophomonas-like and Cytophaga-like bacteria, isolated from the same dune soils, were only slightly stimulated by exposure to fungal hyphae. [KEYWORDS: Biological-control; serratia-marcescens; ammophila-arenaria; plant-pathogens; borne fungi; chitinase; bacteria; maltophilia; allosamidin; strain]
U2 - 10.1128/AEM.67.8.3358-3362.2001
DO - 10.1128/AEM.67.8.3358-3362.2001
M3 - Article
SN - 0099-2240
VL - 67
SP - 3358
EP - 3362
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 8
ER -