Community structure and associated networks of endophytic bacteria in pea leaves during different developmental stages

Background and aims Endophytic bacteria of leaves play a crucial role in plant development, but how structure and co-occurrence networks within these communities respond to seed and soil microbial communities is unknown. Methods To address this, endophytic bacteria of pea (Pisum sativum L.) seedling leaves (SL) after growing 3 and flowering leaves (FL) after 6 weeks were studied using Illumina sequencing of 16S rRNA gene. Results Richness and diversity of endophytic bacteria of FL were similar to non-planted soil (NS) and were higher than SL and seeds (S), while those of SL endophytic bacteria were similar to S. PCoA analysis showed endophytic bacterial community was dynamic during the developmental stage. At the genus level, Bacteroides was enriched and dominant at SL and decreased at FL, whereas Pantoea, Helicobacter and Coriobacteriaceae_UCG_002 tended to be enriched and dominant at FL. Interestingly, the endophytic bacterial community at FL was similar to those at NS. Besides, S and SL networks both had higher modular structures than FL network. Among networks constructed by the combined dataset, the ecosystem of S – SL, S – FL and SL - FL had more microbial interaction than other ecosystems (SL – NS and FL - NS), while the SL – NS and FL - NS ecosystems showed the higher modularity indicating the more special and resistant to secondary extinction species existed. Conclusions In our present study, bacteria from seeds and soils play a critical role for endophytic bacterial community of pea leaves at its developmental stage.