Triple combinations with PGPB stimulate plant growth in micropropagated banana plantlets

• PGPB evaluated presents potential for enhancing the quality of banana plantlets.
• The isolates EB-40 plus EB-51 provided an increase of 174% in the root dry weight.
• PGPB promoted total accumulation for all macro elements and for B, Fe and Mn.
• The isolates evaluated can be applied to increase plant growth and microbial diversity.

Twenty different triple combinations of plant growth promoting bacteria (PGPB) were tested on the micropropagated banana plantlet cultivar Prata Anã in terms of growth and nutrient uptake. The experiment was arranged in a randomized design with 22 treatments (20 triple bacteria combinations and two controls) and three replicates. The maximum increments observed for pseudostem height and pseudostem girth were 42.0% and 34.5%, respectively. For aerial dry weight, five triple combinations of PGPB (treatments 6, 8, 9, 10 and 11) presented superior averages compared to control 1 (no bacteria inoculation). The combination of a Bacillus sp., repeated twice, plus a Lysinibacillus sp. (EB40 + EB53) provided an increase of 174% in the root dry weight. The triple combinations with PGPB also promoted significant differences in the total accumulation in aerial dry weight for all of the analyzed macroelements. Increases in the total accumulation of microelements under triple inoculation were observed for B, Fe and Mn. These results revealed that B. subtilis (EB-40), Bacillus pumilus (EB-51), Lysinibacillus sp. (EB-53), Paenibacillus sp. (EB-144) and Bacillus sp. (EB-194) have the potential to be exploited as inoculants to improve the plant growth of banana plantlets. Moreover, these selected species can be applied to increase soil microbial diversity, as well as soil quality and soil health.