Antifungal activity and action mechanisms of yeasts isolates from citrus against Penicillium italicum

Author(s)

da Cunha, Tatiane ^[1] ; Ferraz, Luriany Pompeo ^[1] ; Wehr, Pitt Paul ^[2] ; Kupper, Katia Cristina ^{[1, 3]}

Affiliation

^[1] Univ Estadual Paulista Julio de Mesquite Filho, UNESP, BR-14884900 Jaboticabal, SP - Brazil

^[2] Univ Fed Sao Carlos, UFSCar, BR-13600970 Araras, SP - Brazil

^[3] Ctr Citricultura Sylvio Moreira, Inst Agron, Rod Anhanguera, Km 158, BR-13490970 Cordeiropolis, SP - Brazil

• Document type: Journal article
• Source: International Journal of Food Microbiology; v. 276, p. 20-27, JUL 2 2018.
• Web of Science Citations: 1

Abstract

Penicillium italicum (Blue mold) is a major postharvest disease of citrus. An alternative to controlling the disease is through the use of yeasts. The purpose of the present study was to screen effective yeast antagonists against P. italicum, isolated from soil, leaves, flowers, and citrus fruits, to assess the action mechanisms of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of blue mold. The in vitro assays showed that six yeast strains inhibited up to 90% of the pathogen's mycelial growth. In vivo assays, evaluating the incidence of blue mold on sweet oranges, the strains ACBL-04, ACBL-05, ACBL-10 and ACBL-11 were effective, demonstrating the potential for the blue mold control when preventively applied, whereas the ACBL-08 strain showed a high potential to preventive and curative applications. Additional studies on the modes of action of these yeast strains showed that most of the evaluated yeast strains did not produce antifungal substances, in sufficient quantities to inhibit the pathogen growth. Competition for nutrients was not a biocontrol strategy used by the yeast strains. The `killer' activity might be the main action mechanism involved in P. italicum biocontrol. This study indicated that the multiple modes of action against the pathogen presented by yeasts may explain why these strains provided P. italicum control under in vitro and in vivo conditions. However, further studies in future might be able to elucidate the `killer' activity and its interaction with pathogen cells and the bioproduct production using Candida stellimalicola strains for control postharvest diseases. (AU)

• FAPESP's process: 11/13874-3 - SELECTION AND IDENTIFY OF YEASTS TO BIOCONTROL OF PATHOGENS IN POSTHARVEST OF CITRUS
• Grantee: Tatiane da Cunha
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 11/13006-1 - Isolation and selection of yeasts to biocontrol of pathogens in postharvest of citrus
• Grantee: Katia Cristina Kupper
• Support Opportunities: Regular Research Grants