Developing composite biocontrol agents based on microbiome dynamics during postharvest storage of tomatoes

Abstract

Single antagonistic microorganisms introduced into the microbial community on the fruit surface often show poor adaptation, resulting in less efficient and inconsistent pathogen inhibition, whereas the interaction of composite microorganisms can increase their ability to combat plant diseases. This study used high-throughput sequencing techniques to explore the dynamics of bacterial and fungal communities on the surface of postharvest tomatoes during storage. Subsequently, potentially beneficial core microorganisms were identified based on correction correlations with one another, and microbial formulations were developed using the isolated beneficial core microorganisms with control efficacy. Based on the microbiome analysis results, two pathogens were screened and identified as Alternaria tenuissima and Cladosporium cladosporioides. Among the five potentially beneficial core microorganisms that were isolated, Bacillus velezensis B1, Pantoea agglomerans B10, and Meyerozyma caribbica Y9, demonstrated safety and highest control efficacy. Considering the affinity between strains, M. caribbica Y9 was combined with either P. agglomerans B10 or B. velezensis B1 to formulate composite microorganisms. The in vivo results demonstrated that all composite microorganisms were more effective in controlling the postharvest diseases caused by A. tenuissima and C. cladosporioides than the single microorganism and P. agglomerans B10 and M. caribbica Y9 at the ratio of 2:1 being the most effective. Therefore, the composite microorganisms formulated with the isolated strains from fresh tomatoes could significantly enhance the control effect, demonstrating strong potential for inhibiting postharvest diseases in tomatoes and promising prospects for widespread application.