Analysis Of Endophytic Bacteria Diversity In Rice Seeds And Definition Of Core Microbiome

It has been demonstrated that bacteria inhabiting plant tissues play crucial roles for the plant growth and health.However,how to determine its core microbiome of plants is still a challenge.In plant microbiome research,recent studies have confirmed that there are abundant bacterial communities in plant seeds,which may become the source of the next generation of endophytes,and transmit among generations vertically.Compared with the rhizosphere and inter-foliar microbes of plants,the research on seeds related microorganisms is still very weak,especially the study of endophytic bacteria.In this study,Illumina high-throughput sequencing technology was used to investigate the endophytic bacteria of six genotypes of rice parental seeds and their offspring roots,stems and seeds endophytic flora and rhizosphere bacteria to reveal the effects of rice genotype and environment on the structure and diversity of rice roots,stems and seeds endophytic flora and rhizosphere bacteria,and to determine the endogenous core bacterial flora of rice seeds.In addition,source tracker technology was used to explore the source of endophytic bacteria in rice,and to explore whether rice endophytic bacteria can be vertically transmitted and its source pathway.The results obtained are as follows:a)The effects of genotypes and environment on the endphytic bacteria in rice: the endophytic group Shannon,Simpson and Chao indexes and PCoA results of rice tissues showed that genotypes had no significant effect on rice rhizosphere microbial community structure,however,there were significant effects on the community structure for rice roots,stems and seeds.The environment had significant effects on the ?-diversity,composition and structure of rhizosphere microorganisms,roots,stems and seed endophytic communities.Environmental variables were more important for the shaping of endophytic bacterial community structure.b)Endophytic resources in rice seeds were very rich,and there were 3 advantages at the phlum level: Proteobacteria,Firmicutes and Actinobacteria;Enterobacteriaceae was the most dominant family at the level of the family;the Venn diagram showed that there were 13 100% shared OTUs in the parental and progeny endophytic bacteria,and 10 of them belonged to Pantoea;there were 111 80% shared OTUs in the parental and progeny seed endophytes,and 67 OTUs belonged to the Pantoea.These OTUs were the key nodes in the ecological network.In summary,the endogenous core microorganisms of rice seeds were Pantoea.c)Source tracker analysis showed that endophytic bacteria could transmitted vertically between seeds through roots and stems,and endophytes in progeny seeds were mainly derived from parental seeds and stem endophytic bacteria.