Conservation and Dynamics of Maize Seed Endophytic Bacteria Across Progeny Transmission

Maize (Zea mays L.) is an important cereal crop species for food, feedstock and industrial material. Maize seeds host a suitable ecosystem for endophytic bacteria, facilitating seed germination and seedling growth. However, the inheritance, diversity and potential function of seed endophytic bacteria in maize remain largely unexplored. In this study, the endophytic bacteria in the seeds of maize inbred line WU109 collected during three consecutive seasons were identified using 16S rDNA sequencing. Core community composition was essentially consistent across three seed generations and two planting locations. In total, 212 operational taxonomic units (OTUs) belonging to 11 phyla were identified, among which proteobacteria was the dominant phylum. Fifty-six OTUs were conserved across three seed generations. Within them, 16 OTUs were core components and the dominant OTUs were Ralstonia solanacearum, Delftia tsuruhatensis, Bacillu svelezensis and Shigella boydii, accounting for 60% of the total abundance of OTUs. COG and KEGG analyses showed that the function of seed endophytic bacteria was mainly enriched in metabolic processes, especially in amino acid, carbohydrate and energy metabolism. Taken together, the results suggested that the community of maize seed endophytic bacteria was likely co-shaped by both genetic determination and the environment, while the core constitutes of seed endophytes were largely conserved due to transgenerational transmission. Establishing the mutualistic link between the maize seed and its endophytic bacteria enables the exploitation of the potential of endophytes for enhancing crop production. This finding provides a reference to better understand the inheritance and composition of seed core endophytic bacteria in maize.