Investigation on diversity and population succession dynamics of endophytic bacteria from seeds of maize (Zea mays L., Nongda108) at different growth stages

Plant seeds are carriers of both beneficial bacteria and pathogens. Using the 16S rRNA gene clone library technique, we conducted a preliminary study on the community diversity and population succession dynamics of endophytic bacteria in seeds of reciprocal cross hybrid maize at different seed developmental stages. In both hybrid lines (108A and 108B), more types of endophytic bacteria were found at the proembryo-forming stage than in the other two stages, including 29 and 23 bacterial operational taxonomic units (OTUs), respectively. Undibacterium (39.20 and 30.00 % in 108A and 108B, respectively) was the first dominant bacterium to appear. At the milky stage, fewer types of endophytic bacteria in 108A and 108B appeared, including 18 and 16 OTUs, respectively, and the abundance of the dominant genus Burkholderia in the two seed samples reached 73.38 and 80.43 %, respectively. Limnobacter appeared as the second and third endophytic dominant bacterium in 108A (4.55 %) and 108B (5.07 %), respectively, in both seed samples. At the dough stage, the abundance of the first dominant bacterium, Burkholderia, in 108A and 108B was 78.26 and 84.80 %, respectively. Pantoea appeared as the second endophytic dominant bacterium in the both seeds (9.42 and 4.80 % in 108A and 108B, respectively). This is the first study on endophytic bacteria present during several crucial stages of the dynamic grain growth process of plant seeds conducted using culture-independent methods.