Epiphytic bacteria from Tacinga inamoena (K. Schum.) N.P. Taylor & Stuppy improve plant growth in cucumber seedlings

The phyllosphere of host plants harbors microorganisms that represent a novel source of agricultural bioinputs. This unique microbiome opens a promising frontier for developing innovative agricultural alternatives. In this study, we evaluated the potential of Brevibacillus sp. UPT4 and Pantoea sp. SPM1, two epiphytic bacterial strains of Tacinga inamoena isolated from the Caatinga biome. In vitro assays exhibited plant growth-promoting traits, such as auxin production, nitrogen fixation, and tolerance to abiotic stresses. Under greenhouse conditions, cucumber plants inoculated with the strains and their consortium exhibited significant increases (p < 0.05) in shoot and root parameters, ranging from 13.58% to 194.86% when compared to the control treatment. Redundancy analysis (RDA) indicated that most of the variability observed in the biometric parameters is associated with the plant growth-promoting reported in this study. These results highlight the potential of epiphytic bacteria from semi-arid land as a promising candidate for the development of new bioinputs, offering an innovative tool for sustainable agriculture.