Biological control activity of killer yeast clavispora lusitaniae 146 against penicillium digitatum in lemons

Abstract

Postharvest decays caused by Penicillium digitatum are responsible of significant economical losses on citrus industry worldwide. In spite of the disadvantages for human health and the environment, chemical fungicides are still widely used for the control of fungal diseases. A native killer strain of Clavispora lusitaniae 146, which previously proved to be effective against green mold in lemons, has been further tested in controlled conditions as a biological and safer alternative to the use of synthetic fungicides. The aim of this work was to determine C. lusitaniae 146 protection efficiency by varying yeast suspension concentrations and dipping times. On the other hand, wound colonization ability and compatibility with commercial waxes of the killer yeast were also evaluated. We showed that strain 146 protection efficiency remained high, even at the lowest yeast concentration used and for all different exposition times. Wounds analysis by scanning electron microscopy confirmed that C. lusitaniae 146 showed an evident wound colonization ability on lemons, being able to develop at both low and room temperatures. Besides that, C. lusitaniae 146 was able to survive in one of the major natural waxes used by local lemon packinghouses at both storage conditions, after 7 and 40 days at 25 and 8°C, respectively; while the tested synthetic wax was not compatible with strain 146. All these results support the potential practical application of C. lusitaniae 146 as a biological agent for postharvest protection of lemons fruits against P. digitatum.