Evaluation of yeasts obtained from Antarctic soil samples as biocontrol agents for the management of postharvest diseases of apple (Malus × domestica)


Correspondence: Silvana Vero, Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, UdelaR, Gral. Flores 2124, Montevideo, CC 11800, Uruguay. Tel.: +598 292 44209; fax: +598 292 41906; e-mail: svero@fq.edu.uy


Psychrotrophic yeasts were isolated from Antarctic soils, selected based on their ability to grow in apple juice at low temperatures, and were evaluated as potential biocontrol agents for the management of postharvest diseases of apple during cold storage. Among the species recovered, an isolate of Leucosporidium scottii, designated At17, was identified as a good biocontrol agent for blue and gray mold of two apple cultivars. The selected isolate produced soluble and volatile antifungal substances that were inhibitory to apple pathogens. Siderophore production was also demonstrated, but it did not appear to play a role in pathogen inhibition. The selected yeast had the capacity to form a biofilm when grown in apple juice, which is considered an important attribute of postharvest antagonists to successfully colonize wounds and intact fruit surfaces. At17 was resistant to commonly used postharvest fungicides, so application of a combination of low-dose fungicide along with the biocontrol agent could be used as an integrated management practice.