Activation of tyrosinase in Agaricus bisporus strains following infection by Pseudomonas tolaasii or treatment with a tolaasin-containing preparation

Soler‐Rivas, Cristina; Arpin, N.; Olivier, Jean-Marc; Wichers, Harry J.

doi:10.1017/s0953756296002729

Cited by 66 publications

(55 citation statements)

References 16 publications

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“…Both induction and inhibition of phenoloxidase activity have been reported in other fungai-bacterial interactions. Bacillus subtilis cells and extracts were found to induce laccase in the wood-decaying basidiomycete Hypholoma fasciculare (8), and Pseudomonas tolaasii enhanced tyrosinase activity in Agaricus bisporus fruit bodies by the action of a metabolite resembling viscosinamide (27). Exposure of the mycoparasite Phanaerochaete magnoliae and saprophyte Trichoderma viride to growthinhibiting volatiles from soil bacteria inhibited laccase and induced or inhibited tyrosinase, depending on the bacterial strain (16).…”

Section: Discussionmentioning

confidence: 99%

Induction of Laccase Activity in Rhizoctonia solani by Antagonistic Pseudomonas fluorescens Strains and a Range of Chemical Treatments

Crowe¹,

Olsson²

2001

Appl Environ Microbiol

122

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Fungi often produce the phenoloxidase enzyme laccase during interactions with other organisms, an observation relevant to the development of biocontrols. By incorporating the laccase substrate 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into agar, we analyzed laccase induction in the plant-pathogenic fungus Rhizoctonia solani when paired against isolates of the soil bacterium Pseudomonas fluorescens. Substantial induction of R. solani laccase was seen only in pairings with strains of P. fluorescens known to produce antifungal metabolites. To study laccase induction further, a range of chemical treatments was applied to R. solani liquid cultures. p-Anisidine, copper(II), manganese(II), calcium ionophore A23187, lithium chloride, calcium chloride, cyclic AMP (cAMP), caffeine, amphotericin B, paraquat, ethanol, and isopropanol were all found to induce laccase; however, the P. fluorescens metabolite viscosinamide did not do so at the concentrations tested. The stress caused by these treatments was assessed by measuring changes in lipid peroxidation levels and dry weight. The results indicated that the laccase induction seen in pairing plate experiments was most likely due to calcium or heat shock signaling in response to the effects of bacterial metabolites, but that heavy metal and cAMP-driven laccase induction was involved in sclerotization.Rhizoctonia solani is a soil-living plant-pathogenic fungus which attacks a wide range of crop plants, including sugarbeet, potato, and rice. Seeds and seedlings are particularly susceptible to this fungus, which persists in soil in the form of resistant sclerotia. Fungicides can be used to control R. solani, but recently attention has focused on the development of biocontrol techniques. To this end, strains of the bacterium Pseudomonas fluorescens that are antagonistic to R. solani have been isolated and are currently being evaluated as biocontrol agents in our department. The most promising strain is P. fluorescens DR54, which produces the antifungal depsipeptide metabolite viscosinamide (18).Inevitably, most fungi will encounter competitive or antagonistic organisms, whether bacterial, fungal or animal, during their life cycles. Fungi engaged in such competition frequently produce secondary metabolites, extracellular phenol-oxidizing enzymes, and differentiated structures in the zone of conflict (2,4,8). These responses may be critical in determining the outcome of a biocontrol treatment.Our first aim was to study the induction pattern of the fungal phenol-oxidizing enzyme laccase in interactions between R. solani and P. fluorescens and how this related to the characteristics of different P. fluorescens strains. Laccase, ubiquitous in fungi and flexible in function (28), is often induced during antagonistic interactions, and R. solani has been shown to possess four laccase genes (29). Our second aim was to determine the pathways of laccase induction in R. solani and relate these to the effects of antagonistic bacteria. We believed that this work would aid the...

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Section: Discussionmentioning

confidence: 99%

Induction of Laccase Activity in Rhizoctonia solani by Antagonistic Pseudomonas fluorescens Strains and a Range of Chemical Treatments

Crowe¹,

Olsson²

2001

Appl Environ Microbiol

122

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“…The suspensions were prepared according to Soler-Rivas et al (1997), using optical density at 450 nm as a measure of bacterial concentration (Olivier et al, 1978). The correlation of O.D.…”

Section: Bacterial and Spore Suspension Preparationmentioning

confidence: 99%

“…The correlation of O.D. with cell concentration (cfu ml −" ) was calculated as in Soler-Rivas et al (1997).…”

Section: Bacterial and Spore Suspension Preparationmentioning

confidence: 99%

“…Mushrooms of 30-40 mm cap diam., at stage 2 or 3 (classification according to Hammond & Nichols, 1975) from the first flush, were harvested and prepared as in Moquet, Mamoun & Olivier (1996), inoculated with 300 µl of the bacterial suspensions, or the spore dilutions as described in Soler-Rivas et al (1997) and incubated for 2 d.…”

Section: Inoculation Proceduresmentioning

confidence: 99%

“…When activated, it can oxidase phenolic compounds into brown melanins (Boekelheide et al, 1979 ;Soulier & Arpin, 1993 ;Jolivet et al, 1995). It was activated during natural senescence (Burton, 1988), and also during infection by Pseudomonas tolaasii or exposure to its toxin, tolaasin, causing brown blotch disease symptoms (Soler-Rivas et al, 1997).…”

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