Journal Article

In vitro attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa

Buck, J.W, Allen, T.W, Burpee, L.L

2004

Overview

The ability of yeasts to attach to hyphae or conidia of phytopathogenic fungi has been speculated to contribute to biocontrol activity on plant surfaces. Attachment of phylloplane yeasts to Botrytis cinerea, Rhizoctonia solani, and Sclerotinia homoeocarpa was determined using in vitro attachment assays. Yeasts were incubated for 2 d on potato dextrose agar (PDA) prior to experimentation. A total of 292 yeasts cultured on PDA were screened for their ability to attach to conidia of B. cinerea; 260 isolates (89.1%) attached to conidia forming large aggregates of cells, and 22 isolates (7.5%) weakly attached to conidia with 1 or 2 yeast cells attached to a few conidia. Ten yeasts (3.4%), including 8 isolates of Cryptococcus laurentii, 1 isolate of Cryptococcus flavescens, and an unidentified species of Cryptococcus, failed to attach to conidia. All non-attaching yeasts produced copious extracellular polysaccharide (EPS) on PDA. Seventeen yeast isolates did not attach to hyphal fragments of B. cinerea, R. solani, and S. homoeocarpa after a 1 h incubation, but attachment was observed after 24 h. Culture medium, but not culture age, significantly affected the attachment of yeast cells to conidia of B. cinerea. The 10 yeast isolates that did not attach to conidia when grown on agar did attach to conidia (20%-57% of conidia with attached yeast cells) when cultured in liquid medium. Attachment of the biocontrol yeast Rhodotorula glutinis PM4 to conidia of B. cinerea was significantly greater at 1 × 10 7 yeast cells·mL -1 than at lower concentrations of yeast cells. The ability of yeast cells to attach to fungal conidia or hyphae appears to be a common phenotype among phylloplane yeasts.Key words: adhesion, biological control, Cryptococcus laurentii, Rhodotorula glutinis.

• Publisher: NRC Research Press,National Research Council of Canada,Canadian Science Publishing NRC Research Press
• Subject: adhesion / Aggregates / Ascomycota / Ascomycota - physiology / Biological and medical sciences / Biological control / biological control agents / biosynthesis / Botrytis / Botrytis - physiology / Botrytis cinerea / Cell Adhesion / Cell adhesion & migration / Cell culture / conidia / Cryptococcus / Cryptococcus (Hyphomycetes) / Cryptococcus - physiology / Cryptococcus flavescens / Cryptococcus laurentii / Fundamental and applied biological sciences. Psychology / fungal antagonists / Fungi / Fungi - metabolism / Fungi - physiology / Genotype & phenotype / Growth, nutrition, metabolism, transports, enzymes. Molecular biology / Incubation / metabolism / Microbiology / Mycological methods and techniques used in mycology / Mycology / Ornamental plants / phylloplane fungi / physiology / plant pathogenic fungi / Polysaccharides / Polysaccharides - biosynthesis / Potatoes / Rhizoctonia / Rhizoctonia - physiology / Rhizoctonia solani / Rhodotorula / Rhodotorula - physiology / Rhodotorula glutinis / Sclerotinia homoeocarpa / Solanum tuberosum / Thanatephorus cucumeris / Yeast / Yeasts / Yeasts - metabolism / Yeasts - physiology