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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #332184
Title: Potential role of exoglucanase genes (WaEXG1 and WaEXG2) in the biocontrol activity of Wickerhamomyces anomalous

Author
item PARAFATI, LUCIA - University Of Catania
item CIRVILLERI, GABRIELLA - University Of Catania
item RESTUCCIA, CRISTINA - University Of Catania
item Wisniewski, Michael

Submitted to: Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2016
Publication Date: 2/1/2017
Citation: Parafati, L., Cirvilleri, G., Restuccia, C., Wisniewski, M.E. 2017. Potential role of exoglucanase genes (WaEXG1 and WaEXG2) in the biocontrol activity of Wickerhamomyces anomalous. Microbial Ecology. 73:876-884.

Interpretive Summary: Various yeast species have been used as biocontrol agents to manage postharvest diseases in fruits. Understanding how these yeasts are able to inhibit or prevent the growth and development of pathogenic fungi that cause postharvest diseases is critical for their efficient use. This knowledge can also be used to develop selective parameters for choosing potentially superior yeast antagonists. The present study looked at the role of two secreted glucanases (enzymes released by the yeast that degrade the cell walls of other fungi) in the biocontrol activity exhibited ty the yeast, Wickerhamomyces anomalus. Results indicated that the expression of one of the genes that code for one of the glucanases secreted by this yeast is stimulated by the presence of cell walls of two postharvest pathogens. This information will be used to develop a better understanding of how yeasts can control pathogenic fungi and to develop a strategy for the selection of superior yeast antagonists.

Technical Abstract: The use of yeasts, including Wickerhamomyces anomalus, as biocontrol agents against fungi responsible for postharvest diseases of fruits and vegetables has been investigated for the past two decades. Among a variety of killer mechanisms, the production of glucanases coded by the genes WaEXG1 and WaEXG2 have been reported to play a role in the ability of yeast to inhibit other fungi. The objective of the study was to determine the expression of these genes by RT-qPCR, utilizing gene-specific primers, when W. anomalus was grown on grape berries and oranges that were either non-inoculated or inoculated with Botrytis cinerea or Penicillium digitatum, or in minimal media supplemented with cell walls of various plant pathogens and different amounts of glucose. Results indicated that WaEXG2 was more responsive than WaEXG1 to the nutritional environment (including the addition of glucose to cell walls media) in vitro and appeared to play a greater role in the cellular metabolism of W. anomalus. WaEXG2 expression also appeared to be more responsive to the presence of cell walls of P. digitatum and B. cinerea than other fungal species, whereas, the same level of induction was not seen in vivo when the yeast was grown in wounded/pathogen inoculated fruits.