Complete control of <i>Penicillium expansum</i> on apples fruit by using a combination of antagonistic yeast <i>Candida oleophila</i>

Victor Guerrero1*, Cesar Guigon2, David Berlanga3, and Damaris Ojeda1
Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vitro as biocontrol agents against Penicillium expansum on postharvest ‘Golden Delicious’ apples (Malus domestica Borkh.) in Chihuahua, Mexico. The in vivo and in vitro activity of exo-β-1,3-glucanase was measured as a possible biocontrol mode of action for C. oleophila. Mean disease incidence caused by P. expansum was 0.3% for apples treated with fludioxonil + ciprodinil, which were used as a positive control, and 1% for fruits treated with a combination of the three C. oleophila strains; the effects of these treatments were significantly equivalent. Disease incidence in control apples was 39% and was significantly different from the other treatments. The in vivo exo-β-1,3-glucanase activity began at 24 h and peaked at 72 and 96 h for all treatments. Strain L06 had the highest activity (7.96 nKat) and a specific activity of 2.92 nKat μg-1. Candida albicans had the lowest activity (2.83 nKat) and a specific activity of 0.67 nKat μg-1. The highest in vitro activity was for C. albicans (85.03 nKat) and the lowest for strain L06 (78.2 nKat). Significant differences in both in vivo and in vitro enzymatic activity were observed between strain L06 and C. albicans. Polynomial regression analysis (R2 = 0.96 in vitro and 0.68 in vivo) indicated that increased enzymatic activity was associated with reduced fruit disease incidence. The production of exo-β-1,3-glucanase by C. oleophila is a possible mode of action for the efficient biocontrol of P. expansum on postharvest apples.
Keywords: Biocontrol, Malus domestica, yeasts
1Universidad Autónoma de Chihuahua, Facultad de Ciencias Agrotecnológicas, Campus Cuauhtémoc, Chih. Av. Presa de La Amistad 2015, Cuauhtémoc, Chihuahua C.P. 31510, México. *Corresponding author (vguerrero@uach.mx).
2Centro de Investigación en Recursos Naturales, DGETA-SEP, Salaices, Chihuahua, México.
3Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Cuauhtémoc, Av. Río Conchos s/n, Parque Industrial, Apdo. Postal 781, Cuauhtémoc, Chihuahua C.P. 31570, México.