# Effects of Different Varieties of Camellia oleifera on Root-Associated Bacterial Community Structure and Co-Occurrence Network

## TL;DR

This study explores how different varieties of Camellia oleifera affect the structure and interactions of root-associated bacteria, revealing insights into plant-microbe relationships.

## Contribution

The study identifies key bacterial taxa and co-occurrence networks in different root compartments of C. oleifera varieties.

## Key findings

- The rhizosphere of Camellia oleifera has the highest bacterial diversity and richness compared to other root compartments.
- The variety ‘Huaxin’ harbors a distinct bacterial community structure compared to other cultivars.
- Colidextribacter, Uliginosibacterium, and Aliidongia are key taxa maintaining bacterial community stability.

## Abstract

Camellia oleifera is an important woody oil crop in China. Root-associated bacteria play critical roles in plant growth and health. This study investigated the bacterial community structure and co-occurrence networks in non-rhizosphere soil, rhizosphere soil, rhizosphere, and endosphere of three C. oleifera varieties (‘Huashuo’, ‘Huajin’, ‘Huaxin’) using high-throughput sequencing. The results showed that root compartments significantly affected bacterial diversity and composition, with the rhizosphere having the highest diversity. Varietal differences altered the bacterial community structure, especially for ‘Huaxin’, which harbored a distinct community. Acidothermus, Sphingomonas, and Actinospica were identified as key taxa maintaining community stability. This study provides insights into the plant-microbe interactions in C. oleifera and a theoretical basis for microbiota-based crop management.

This study investigates the bacterial community structure and diversity across different root compartments (non-rhizosphere soil, rhizosphere soil, rhizosphere, and endosphere) of Camellia oleifera and their associations with three cultivars (‘Huashuo’, ‘Huajin’, ‘Huaxin’). High-throughput sequencing and bioinformatics analyses were performed to characterize the bacterial communities. A total of 22 phyla, 59 classes, 155 orders, 268 families, 523 genera, 929 species, and 2045 operational taxonomic units (OTUs) were identified. Alpha diversity indices (Shannon, Simpson, Chao1) showed no statistically significant differences among the three cultivars, but varied significantly across root compartments. The rhizosphere exhibited the highest bacterial diversity and richness, which was significantly higher than that in the endosphere. At the phylum level, Proteobacteria, Chloroflexi, Actinobacteriota, Acidobacteriota, Firmicutes, and Bacteroidetes dominated the communities. Significant differences were observed in the relative abundance of dominant genera (e.g., Proteus, actinomycetes) among varieties and root compartments. PCoA analysis revealed that ‘Huaxin’ had a distinct bacterial community structure compared to ‘Huashuo’ and ‘Huajin’, while the endosphere was separated from other compartments. Interaction network analysis indicated that most bacterial interactions were positive, with Colidextribacter, Uliginosibacterium, and Aliidongia showing the highest centrality, suggesting their key roles in maintaining community stability. This study provides novel insights into the distribution patterns and driving factors of root-associated bacteria in C. oleifera, laying a theoretical foundation for future research on disease control and quality improvement of this crop.