Spatial differences in Casuarina equisetifolia L. endophyte community structure

Casuarina equisetifolia, a fast-growing, abundant tree species on the southeastern coast of China, plays an important role in protecting the coastal environment, but the ecological processes that govern microbiome assembly and within-plant microorganism transmission are poorly known. In this paper, we used ITS and 16S amplification techniques to study the diversity of fungal and bacterial endophytes in critical plant parts of this species: seeds, branchlets, and roots. Additionally, we examined the litter of this species to understand the process of branchlets from birth to litter. We uncovered a non-random distribution of endophyte diversity in which branchlets had the greatest and seeds had the lowest endophytic fungal diversity. In contrast, litter endophytic bacteria had the highest diversity, and branchlets had the lowest diversity. As for fungi, a large part of the seed microbiome was transmitted to the phyllosphere, while a large part of the bacterial microbiome in the seed was transmitted to the root. Our study provides comprehensive evidence on diversity, potential sources, and transmission pathways for non-crop microbiome assembly and has implications for the management and manipulation of the non-crop microbiome in the future.