Raw data on the effects of bacterial isolates on the growth promotion of maize plantlets

Plant growth-promoting bacteria (PGPB) may enhance plant growth and health through several mechanisms, contributing for sustainable agriculture. We isolated and characterized endophytic bacteria from stems of landrace maize (<i>Zea mays</i> L.) grown under low-input and organic systems in southern Brazil. The 16S rRNA analysis revealed 83 isolates within 14 genera, including α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Actinomycetia, and Bacilli classes. The synthesis of indolic compounds was widespread among the strains, as well as the enhancement of N concentration in N-free media, a putative capacity for biological nitrogen fixation. Phosphate solubilization prevailed in <i>Burkholderia</i> and <i>Paraburkholderia</i> strains, while siderophores production was observed in all genera, except <i>Microbacterium</i>. Inoculation with selected strains confirmed growth-promotion on maize plantlets, particularly <i>Sphingomonas</i> sp. CNPSo 2378 and <i>Bacillus</i> <i>velezensis</i> CNPSo 2384, whose genomes were sequenced and revealed PGPB features and evolutionary relationships, shedding light on the diversity, functional traits, and occurrence in low-input and organic agricultural systems.