Abstract:

To explore the various potential functions of strawberry endophytes and provide new strain resources for the subsequent development of endophytic microbial agents, the strawberry cultivar Hongyan was used as the research object to isolate and screen endophytes. The plate method was employed to determine their growth-promoting abilities, while the five-point confrontation assay was used to evaluate their antagonistic activities against four common strawberry pathogens, namely Botrytis cinerea, Fusarium oxysporum, Colletotrichum gloeosporioides and Colletotrichum acutatum. High-throughput sequencing was applied to analyze the community structure and diversity of the endophytes. The results showed that a total of 68 endophytic strains were isolated. Among them, 15 strains had the ability to produce indole-3-acetic acid (IAA), 48 strains could produce siderophores, 8 strains exhibited inorganic phosphorus solubilization capacity, 23 strains had organic phosphorus solubilization ability, 28 strains were capable of producing cellulase, 33 strains could produce protease, 45 strains possessed nitrogen fixation capacity, and 47 strains could release potassium. The antibacterial test results indicated that 14 endophytic strains showed antagonistic activity against all four pathogenic fungi, and 6 other strains exhibited antagonistic effects against at least one pathogen. At the phylum level, the endophytic bacterial community of the tested strawberry was mainly composed of Proteobacteria and Actinobacteria, while the endophytic fungal community was dominated by Ascomycota. At the genus level, the dominant bacterial genera included Streptomyces, Staphylococcus, and Pseudomonas, and the dominant fungal genus was Monographella.

Key words: strawberry, endophyte, growth-promoting function, antagonistic function, pathogen