Citation:Gaballa A., Abeysinghe P.D., Urich G., Matthijs S., De Greve H., Cornelis P., Koedam N.(1997).Trehalose Induces Antagonism towards Pythium debaryanum in Pseudomonas fluorescens ATCC 17400. Appllied and Environmental Microbiogy, 63(11): 4340-4345.
Date:1997-09-03
Abstract:
Pseudomonas fluorescens ATCC 17400 shows in vitro activity against Pythium debaryanum under conditions
of iron limitation. A lacZ reporter gene introduced by transposon mutagenesis into the P. fluorescens ATCC
17400 trehalase gene (treA) was induced by a factor released by the phytopathogen Pythium debaryanum. The
induction of the lacZ gene was lost upon treatment of the Pythium supernatant with commercial trehalase. A
trehalose concentration as low as 1 mM could induce the expression of treA. The mutation did not affect the
wild-type potential for fungus antagonism but drastically decreased the osmotolerance of the mutant in liquid
culture and suppressed the ability of P. fluorescens ATCC 17400 to utilize trehalose as a carbon source. A
subsequent transposon insertion in treP, one of the trehalose phosphotransferase genes upstream of treA,
silenced the lacZ gene. This double mutant restricted fungal growth only under conditions of high osmolarity,
which probably results in internal trehalose accumulation. These data confirm the role of the disaccharide
trehalose in osmotolerance, and they indicate its additional role as an initiator of or a signal for fungal
antagonism.
