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 (Zea mays 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 Burkholderia and Paraburkholderia strains, while siderophores production was observed in all genera, except Microbacterium. Inoculation with selected strains confirmed growth-promotion on maize plantlets, particularly Sphingomonas sp. CNPSo 2378 and Bacillus velezensis 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.