Abstract:[Background] The distribution of endophytic fungi in plants is affected by environmental changes and growth stages. Investigating the shifts in these fungal communities and understanding their interactions during plant growth and storage enhances our ability to harness the positive effects of fungi on plants. [Objective] To investigate the characteristics and variations of endophytic fungal communities in Psidium guajava fruits during different developmental stages, and provide a scientific basis for the in-depth research and utilization of endophytic fungal resources of this plant and the post-harvest control of diseases. [Methods] High-throughput sequencing of ITS was employed to compare the composition of endophytic fungal communities in P.guajava fruits during different developmental stages. [Results] A total of 1 582 892 high-quality endophytic fungal sequences were obtained, involving 566 OTUs belonging to 281 genera, 161 families, 70 orders, 26 classes of 7 phyla. The diversity and abundance of endophytic fungi in P.guajava fruits increased over time before fruit ripening and then decreased as fruit continued to ripen and decay. Ascomycota was the dominant phylum, with the relative abundance being 99.34%, 96.35%, 91.63%, 65.22%, and 100.00% at the flowering, young fruit, fruit expansion, fruit ripening, and fruit decay stages, respectively. The relative abundance of dominant genera was in a descending order of Neopestalotiopsis (39.34%), Colletotrichum (26.54%), and Cladosporium (18.58%). The dominant genera varied among different developmental stages, with Gibberella, Cladosporium, Neopestalotiopsis, and Didymella being dominant at the flowering, young fruit, fruit expansion, and fruit ripening stages, respectively, and Neopestalotiopsis (49.76%) and Colletotrichum (50.00%) being dominant at the decay stage. The topological characteristics of the endophytic fungal network were influenced by different developmental stages. The strongest interaction occurred at the fruit expansion stage and the weakest at the flowering stage. The reciprocal relationship between species was stronger than the competitive one. [Conclusion] P.guajava fruits contained a rich endophytic fungal community, whose composition and interactions varied considerably at different developmental stages. The findings provide reference for the excavation of fungal resources in P.guajava fruits.
