Community structure and associated networks of endophytic bacteria in pea roots throughout plant life cycle

Endophytic bacteria from legume roots and nodules play important roles in regulating plant growth and health. Therefore, the aim is to focus on the community structure and network of pea root endophytes throughout the plant life cycle. We collected five edible pea cultivars to study the endophytic bacterial community during the whole developmental period using Illumina sequencing of 16S rRNA gene. The structure and complexity of root endophytes was significantly affected by the development period and different root endophytes were recruited by peas at different developmental stages. Pea cultivars gave no significant influence on the patterns of root endophytic bacterial community during plant growth. Here, the complexity of root-endophytic bacterial community was the highest at seedling stage and became more and more simple after that. Rhizobium was a dominant root bacteria during the whole developmental stage. The amount of Rhizobium began to accumulate in pea seedling roots, and reached the highest at flowering stage and decreased at the mature stage. The relative abundance of Pseudomonas increased overtime throughout the pea entire life cycle, whereas the amount of Bacteroides decreased overtime. The pea root and nodule endophytes were dominated by Rhizobium, Pseudomonas and Bacteroides. These findings provide an endophyte-based characterization of the reference stock bacteria detail for the establishment of root endophytic bacteria throughout the plant life cycle. Specially, a proper synthetic microbial community to improve pea yields.