Growth Promotion of Phaseolus vulgaris and Arabidopsis thaliana Seedlings by Streptomycetes Volatile Compounds.

are recognized as antipathogenic agents and plant-growth-promoting rhizobacteria. The objective of this study was to evaluate the capacities of four antifungal strains to: produce the substances that are involved in plant growth; solubilize phosphates; and fix nitrogen. The effects of the volatile organic compounds (VOCs) that are emitted by these strains on the growth promotion of and L. (var. Pinto Saltillo) seedlings were also tested. All of the strains produced indole-3-acetic acid (IAA) (10.0 mg/L to 77.5 mg/L) and solubilized phosphates, but they did not fix nitrogen. In vitro assays showed that the VOCs from increased the shoot fresh weights (89-399%) and the root fresh weights (94-300%) in . seedlings; however, these effects were less evident in In situ experiments showed that all the strains increased the shoot fresh weight (11.64-43.92%), the shoot length (11.39-29.01%), the root fresh weight (80.11-140.90%), the root length (40.06-59.01%), the hypocotyl diameter (up to 6.35%), and the chlorophyll content (up to 10.0%) in seedlings. 3-Methyl-2-butanol had the highest effect among the ten pure VOCs on the growth promotion of seedlings. The tested strains favored biomass accumulation in and seedlings.