Evaluation of bacterial isolates from strawberry plants (Fragaria x ananassa Duch.) as biological control agents of Botrytis cinerea.

HIRSCH MAILÉN; BURGES PABLO L.; VILLARREAL NATALIA M.; MARINA MARÍA

Virtual

Congreso; LVII SAIB Meeting - XVI SAMIGE Meeting; 2021

SAIB-SAMIGE

Biological control of diseases in plants is the use of living organisms (known as biological control agents o BCAs) capable to eliminate or suppress the population of pathogens. BCAs can protect the plant via different ways of action: space and nutrient competition with the pathogen, antimicrobial compounds production, biofilms formation, hydrolytic enzymes production, induction of defense responses in the host, among others. In this work, we focus our study on bacteria isolated from strawberry plants as BCAs for Botrytis cinerea, a phytopathogen responsible for severe economic losses for producers. First, 103 bacterial isolates (57 epiphytes and 46 endophytes) were obtained from strawberry leaves and fruits. Then, they were evaluated for their potential antifungal activity by in vitro assays. The inhibition of B. cinerea?s growth by bacteria was tested in two ways: by the synthesis of diffusible and volatile compounds on plates with potato glucose agar (PGA) medium and by the emission of only volatile compounds using two plates placed "mouth-to-mouth" and sealed with parafilm. From the total, 82 strains showed significant differences for the inhibition assay by diffusible/volatile compounds, and 71 for the inhibition by just volatile compounds. Based on the results, 49 bacteria that showed statistical differences in both assays were selected to continue their characterization. Carrying out BOX-PCR, we observed duplicate strains that presented the same molecular pattern of bands. As a result, we have 47 non-redundant bacterial isolates with the capacity to inhibit the in vitro growth of B. cinerea. That is a significant number of potential BCAs of that important phytopathogen to continue studying and identifying other mechanisms of action through which they could exert biocontrol. Further studies will be performed to reduce the number of endophytes and epiphytes with the potential of being used as an eco-friendly alternative strategy to reduce the use of fungicides to control diseases in strawberry plants.