Characterization of antagonistic yeasts for biocontrol applications on apples or in soil by quantitative analyses of synthetic yeast communities

Abstract

Antagonistic yeasts suppress plant pathogenic fungi by various mechanisms, but their biocontrol efficacy also depends on the ability to compete and persist in the environment. The goal of the work presented here was to quantify the composition of synthetic yeast communities in order to determine the competitiveness of different species and identify promising candidates for plant protection. For this purpose, colony counting of distinct species and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS; MALDI biotyping) were used to distinguish different yeast species and to quantify the composition of a synthetic community of six yeasts (Aureobasidium pullulans, Candida subhashii, Cyberlindnera sargentensis, Hanseniaspora sp., Metschnikowia pulcherrima and Pichia kluyveri) over time, on apples and in soil, and in different growth media. These studies revealed important characteristics that predispose the different species for particular applications. For example, the competitiveness and antagonistic activity of C. subhashii was strongly increased in the presence of N‐acetylglucosamin as the sole carbon source, M. pulcherrima and A. pullulans were the strongest competitors on apple, and C. sargentensis competed the best in soil microcosms. Based on these laboratory studies, M. pulcherrima and A. pullulans are promising candidates for biocontrol applications against fungal phyllosphere diseases, while C. sargentensis may hold potential for use against soilborne fungal pathogens. These results document the potential of MALDI‐TOF MS for the quantitative analysis of synthetic yeast communities and highlight the value of studying microorganisms with relevant functions in moderately complex, synthetic communities and natural substrates rather than as individual isolates.

Snf2 controls pulcherriminic acid biosynthesis and antifungal activity of the biocontrol yeast Metschnikowia pulcherrima

“…The yeast Metschnikowia pulcherrima is globally distributed and frequently isolated from the phyllosphere; in particular from flowers and fruits (Slavikova et al , ; Pelliccia et al , ; Vadkertiova et al , ). Competition assays of 40 yeasts against a diverse set of 16 filamentous fungi identified M. pulcherrima as the overall strongest antagonist (Hilber‐Bodmer et al , ) and the same isolate was highly competitive against other antifungal yeasts on apples (Gross et al , ). The species exhibits strong antagonistic activity against apple postharvest diseases caused by Alternaria , Aspergillus , Botrytis, Fusarium, Monilinia and Penicillium species (Piano et al , ; Janisiewicz et al , ; Spadaro et al , ; Saravanakumar et al , ; Turkel et al , ; Ruiz‐Moyano et al , ) and was also identified as a potential biocontrol organism against foodborne pathogens of freshly cut apples (Leverentz et al , ) as well as fungal grape diseases (De Curtis et al , ; Parafati et al , ).…”

Genome, transcriptome and secretome analyses of the antagonistic, yeast-like fungus Aureobasidium pullulans to identify potential biocontrol genes

“…The species A. pullulans and the A. pullulans strain NBB 7.2.1 are strongly antagonistic against several plant pathogens and highly competitive against other yeasts on apple fruits [9,37,38]. Here, A. pullulans NBB 7.2.1 exhibited comparable growth and antagonistic activity as A. pullulans EXF-150, but inhibited F. oxysporum NRRL 26381/CL57 more strongly than A. melanogenum CBS 110374, A. namibiae CBS 147.97, and A. subglaciale EXF-2481 (Figure 1).…”

The Use of Candida pyralidae and Pichia kluyveri to Control Spoilage Microorganisms of Raw Fruits Used for Beverage Production

“…However, many have not yet been explored as potential biocontrol agents against fruit-spoilage organisms. Similarly, P. kluyveri has also been determined as an antagonistic yeast for biocontrol applications [44,45].…”