Effect of Cryptococcus laurentii and calcium chloride on control of Penicillium expansum and Botrytis cinerea infections in pear fruit

This study was conducted to evaluate the efficacy of the biocontrol yeast Cryptococcus laurentii and calcium chloride (CaCl2) in suppressing the blue and gray mold rots in pear fruit wounds and the possible mechanisms involved. The results from the presented investigation showed that combined treatment of pear fruit wounds with C. laurentii and CaCl2 was a much better approach for inhibition of Penicillium expansum and Botrytis cinerea infections than C. laurentii or CaCl2 alone. CaCl2 neither affected the growth of C. laurentii in vitro or in vivo, nor directly inhibited the mold rots in pear fruit. However, CaCl2 was shown to elicit the fruit resistance to mold rots when the time interval between CaCl2-treatment and pathogen-inoculation was increased up to 24 h, being associated with an activation of the peroxidase activity of pear fruit. Therefore, it could be proposed that the mechanism by which CaCl2 reinforced the biocontrol efficacy of C. laurentii was mainly due to its ability to induce the fruit natural resistance. (C) 2012 Elsevier Inc. All rights reserved.