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Antibiosis plays a role in the context of direct interaction during antagonism of Paenibacillus polymyxa towards Fusarium oxysporum
Author(s) -
Dijksterhuis J.,
Sanders M.,
Gorris L. G. M.,
Smid E. J.
Publication year - 1999
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1999.t01-1-00600.x
Subject(s) - antibiosis , paenibacillus polymyxa , antagonism , context (archaeology) , fusarium oxysporum , microbiology and biotechnology , biology , paenibacillus , botany , bacteria , genetics , paleontology , receptor , 16s ribosomal rna
Interaction of Fusarium oxysporum and Paenibacillus polymyxa starts with polar attachment of bacteria to the fungal hyphae followed by the formation of a large cluster of non‐motile cells embedded in an extracellular matrix in which the bacteria develop endospores. Enumeration of fungal viable counts showed that less than one of 36 000 colony‐forming units survived in paired cultures for 71 h. Effective antagonism was not observed below pH 5 and was specific for the bacterial species. Development of F. oxysporum was inhibited in cell‐free filtrates derived from cultures of P. polymyxa , but was much more strongly repressed in the presence of living bacteria. Furthermore, recovery of fungal growth started immediately after addition of antibiotics to paired cultures. Restoration of fungal growth was enhanced in filtrates that were supplemented with MgCl 2 , which suggests that anti‐fungal compounds produced by the bacteria were counteracted by magnesium ions. In paired cultures, fungal counts remained very low, even in the presence of the magnesium salt.This study clearly showed that P. polymyxa antagonizes the plant pathogenic fungus F. oxysporum in liquid medium by means of an interaction process in which the presence of living bacteria is a prerequisite for continuous suppression of fungal growth.