Biocontrol efficacy of Pichia membranaefaciens and Kloeckera apiculata against Monilinia fructicola and their ability to induce phenylpropanoid pathway in plum fruit

Abstract

Strains belonging to the species Pichia membranaefaciens and Kloeckera apiculata were tested as biocontrol agents (BCAs) against brown rot caused by Monilinia fructicola in plum fruit. The two yeast strains demonstrated significant antifungal activities at concentration of 5 × 108 cells/mL. Effective colonization in the wounds and high population size to compete for nutrition and space with pathogen contributed to the control mechanism of P. membranaefaciens and K. apiculata. Besides, P. membranaefaciens and K. apiculata could activate the phenylpropanoid pathway of plum to strengthen its cell wall and prevent pathogenic invasion. Both of the yeasts significantly accelerated activities of related enzymes such as phenylalanine ammonia lyase, cinnamic acid 4-hydroxylase, p-coumaroyl: CoA ligase and peroxidase. Those enzymes enhanced biosynthesis of some active metabolites of plum such as lignin, flavonoid and total phenolics.