Title Analysis of the Abilities of Endophytic Bacteria Associated with Banana Tree Roots to Promote Plant Growth
Author Leandro Fernandes Andrade, Gleika Larisse Oliveira Dorasio de Souza, Silvia Nietsche, Adelica Aparecida Xavier, Marcia Regina Costa, Acleide Maria Santos Cardoso, Marlon Cristian Toledo Pereira, and Débora Francine Gomes Silva Pereira
Address Laboratório de Biotecnologia, Departamento de Ciências Agrárias, Universidade Estadual de Montes Claros, Avenida Reinaldo Viana 2630, Caixa Postal 91, CEP 39440-000, Janaúba, Minas Gerais, Brazil
Bibliography Journal of Microbiology, 52(1),27–34, 2014,
DOI 10.1007/s12275-014-3019-2
Key Words Musa spp. nitrogen fixation, indole-3-acetic acid, phosphate solubilization, Bacillus sp.
Abstract A total of 40 endophytic bacterial isolates obtained from banana tree roots were characterized for their biotechnological potential for promoting banana tree growth. All isolates had at least one positive feature. Twenty isolates were likely diazotrophs and formed pellicles in nitrogen-free culture medium, and 67% of these isolates belonged to the genus Bacillus sp. The isolates EB-04, EB-169, EB-64, and EB-144 had N fixation abilities as measured by the Kjeldahl method and by an acetylene reduction activity assay. Among the 40 isolates, 37.5% were capable of solubilizing inorganic phosphate and the isolates EB-47 and EB-64 showed the highest solubilization capacity. The isolate EB-53 (Lysinibacillus sp.) had a high solubilization index, whereas 73% of the isolates had low solubilization indices. The synthesis of indole-3- acetic acid (IAA) in the presence of L-tryptophan was detected in 40% of the isolates. The isolate EB-40 (Bacillus sp.) produced the highest amount of IAA (47.88 μg/ml) in medium supplemented with L-tryptophan and was able to synthesize IAA in the absence of L-tryptophan. The isolates EB-126 (Bacillus subtilis) and EB-47 (Bacillus sp.) were able to simultaneously fix nitrogen, solubilize phosphate and produce IAA in vitro. The results of this study demonstrated that the isolates analyzed here had diverse abilities and all have the potential to be used as growth-promoting microbial inoculants for banana trees.