Native killer yeasts as biocontrol agents of postharvest fungal diseases in lemons

PEREZ, MARÍA FLORENCIA; CONTRERAS, LUCIANA; GARNICA, NYDIA MERCEDES; FERNÁNDEZ-ZENOFF, MARÍA VERÓNICA; FARÍAS, MARÍA EUGENIA; SEPULVEDA, MILENA; RAMALLO, JACQUELINE; DIB, JULIÁN RAFAEL

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2016 vol. 11

1932-6203

Economic losses caused by postharvest diseases represent one of the main problems of the citrus industry worldwide. The major diseases affecting citrus are the "green mold" and "blue mold", caused by Penicillium digitatum and P. italicum, respectively. To control them, synthetic fungicides are the most commonly used method. However, often the emergence of resistant strains occurs and their use is becoming more restricted because of toxic effects and environmental pollution they generate, combined with trade barriers to international markets. The aim of this work was to isolate indigenous killer yeasts with antagonistic activity against fungal postharvest diseases in lemons, and to determine their control efficiency in in vitro and in vivo assays. Among 437 yeast isolates, 8.5% show to have a killer phenotype. According to molecular identification, based on the 26S rDNA D1/D2 domain sequences analysis, strains were identified belonging to the genera Saccharomyces, Wickerhamomyces, Kazachstania, Pichia, Candida and Clavispora. Killers were challenged with pathogenic molds and strains that caused the maximum in vitro inhibition of P. digitatum were selected for in vivo assays. Two strains of Pichia and one strain of Wickerhamomyces depicted a significant protection (p