Biocontrol features of Clavispora lusitaniae against Penicillium digitatum on lemons

Abstract

Penicillium digitatum is the main pathogen which causes postharvest decays in lemons, and the use of synthetic fungicides is the principal way of controlling these postharvest infections. In our previous work, identifying biological alternatives to the use of fungicides, a killer strain of Clavispora lusitaniae 146, which exhibited highly protective activity against green mold on lemons, was isolated from citrus plants. The aim of the present work was to study the ability of C. lusitaniae 146 to colonize wounds in lemon fruit and its effect on P. digitatum spore germination. Additionally, the protection efficacy of yeast strain 146 against an imazalil-resistant P. digitatum as well as yeast survival on commercial waxes were also evaluated. Results indicated that C. lusitaniae 146 exhibited an evident ability to colonize wounds in lemons and continue to grow at both low and room temperatures. In addition, the use of heat-inactivated cells showed a certain degree of efficacy against fruit decays. The ability of C. lusitaniae 146 to inhibit spore germination and its high efficiency against both sensitive and resistant fungi to fungicides were also demonstrated. Lastly, it was found that C. lusitaniae 146 could survive in natural waxes for 7 d at 25 °C and 40 d at 8 °C. Thus, our studies confirmed the potential industrial use of C. lusitaniae 146 as an effective biocontrol agent against postharvest infections of lemons caused by P. digitatum.