Community structure and niche differentiation of endosphere bacterial microbiome in Camellia oleifera

ABSTRACT Understanding the changes in bacterial community structure in different microenvironments of Camellia oleifera is essential to better explore the benign interaction between beneficial microorganisms and plants. Using Camellia oleifera trees, a Chinese wooden oil plant as a model ecosystem, we characterized the archaeal and bacterial microbiome across five different tissue-level niches using 16S rRNA gene analyses. Our research indicates that the diversity of Camellia oleifera endophytic bacterial communities is highly dependent on the plant compartment. The species replacement process (69.90%) is the dominant factor in the differences in bacterial community structure. The dominant bacteria phyla (Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Chloroflexi, and Verrucomicrobia) of Camellia oleifera show a significant plant compartment (roots, stems, leaves, fruits) enrichment effects. A variety of bacteria (Hymenobacter, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Mesorhizobium, Bradyrhizobium, Bacillus, Ochrobactrum, Pantoea, Pseudomonas, etc.) with nitrogen-fixed potentials are enriched in Camellia oleifera tissue. In addition, the hub bacterial groups of Camellia oleifera are Nitrospira, Haemophilus, Staphylococcus, Ruminiclostridium, and Ochrobactrum. They are widespread colonization in various tissues with a low relative abundance and may play an important role in the nitrogen cycle, host life promotion, and plant defense. This study provides a holistic understanding of the endosphere bacterial community structure, which is one of the most complete ecological niche-level analyses of Camellia oleifera. These results provide a scientific theoretical basis for an in-depth discussion of plant-endosphere microbial interaction and better exploration of benign interaction of beneficial microorganisms and plants. IMPORTANCE Microorganisms inhabited various tissues of plants and play a key role in promoting plant growth, nutritional absorption, and resistance. Our research indicates that the diversity of Camellia oleifera endophytic bacterial communities is highly dependent on the plant compartment. Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Chloroflexi, and Verrucomicrobia are dominant bacteria phyla. The tissues of Camellia oleifera contain various bacteria with nitrogen fixation potential, host life promotion, and plant defense. This study provides a scientific theoretical basis for an in-depth discussion of plant-endosphere microbial interaction and better exploration of benign interaction of beneficial microorganisms and plants. Microorganisms inhabited various tissues of plants and play a key role in promoting plant growth, nutritional absorption, and resistance. Our research indicates that the diversity of Camellia oleifera endophytic bacterial communities is highly dependent on the plant compartment. Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Chloroflexi, and Verrucomicrobia are dominant bacteria phyla. The tissues of Camellia oleifera contain various bacteria with nitrogen fixation potential, host life promotion, and plant defense. This study provides a scientific theoretical basis for an in-depth discussion of plant-endosphere microbial interaction and better exploration of benign interaction of beneficial microorganisms and plants.