Biological control of green and blue molds on postharvest lemon by lactic acid bacteria

Postharvest green and blue molds caused mainly by Penicillium digitatum and P. italicum conduce to economic losses in citrus production. Here, the potential antifungal activity of four lactobacilli strains was assessed against local isolates of these fungi to control postharvest diseases on lemons. Inhibitory activity of L. paraplantarum CRL 1905, L. fermentum CRL 973, L. casei CRL 1110 and L. reuteri CRL1101 strains was assayed by the culture overlay method. Also, inhibition of conidial germination by cell-free supernatants (CFS) obtained from 24 and 48 h-cultures of these lactobacilli strains (CFS24 and CFS48, respectively) was tested by microtiter assay. CRL 1905 showed the strongest fungicidal activity and was selected for further studies. When the antifungal compound/s produced by CRL 1905 strain were investigated, it was observed that the ability of CFS24 to inhibit conidial germination was lost after pH neutralization, inferring an acidic nature of the metabolite/s. Finally, to detect whether CFS24 had a potential application to control of Penicillium rot on lemons, a fruit decay test was performed. It was demonstrated that ten-fold concentrated CFS24 was able to decrease the disease incidence by ∼ 80 %. In conclusion, the use of extracellular components derived from CRL 1905 with antifungal activity could be an eco-friendly alternative to control postharvest decays of lemon. Fil: Volentini, Sabrina Inès. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto Superior de Investigaciones Biológicas. Grupo de Investigación y Desarrollo del Noroeste Argentino | Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas. Grupo de Investigación y Desarrollo del Noroeste Argentino; Argentina Fil: Olmedo, G. M.. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto Superior de Investigaciones Biológicas. Grupo de Investigación y Desarrollo del Noroeste Argentino | Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas. Grupo de Investigación y Desarrollo del Noroeste Argentino; Argentina