Leaf mycobiome across Fabaceae species: Non-nodulating plants exhibit higher fungal diversity

The impact of plant-bacterial symbioses in roots on plant-fungal interactions in distant tissues, such as leaves, remains a significant knowledge gap, particularly for tropical legume trees. In this study, we analyzed the ITS2 sequences of fungal endophytes from eight tropical Fabaceae species, differing in their ability to form root nodules, to explore patterns in foliar fungal community composition. Our findings reveal differences in fungal community richness and composition between nodulating and non-nodulating species, with non-nodulating species hosting a richer and more diverse fungal community. Specifically, non-nodulating plants supported 72 taxonomic orders and 130.5 fungal amplicon sequence variants (ASVs), compared with 45 orders and 42.7 ASVs in nodulating plants. Moreover, 40% of fungal orders were exclusive to non-nodulating species. These patterns provide insights into the diversity of fungal endophytes in tropical legumes and lay the groundwork for future research on plant-microbe interactions. This study emphasizes the need for further exploration of the ecological factors influencing fungal community composition in tropical forest ecosystems.