Characterization of plant growth-promoting traits of bacteria isolated from the rhizosphere of grapevine grown in alkaline and acidic soils

The purpose of this study was to investigate the diversity of cultivable N2-fixing, P-solubilising and siderophores-producing bacteria originated from acidic and alkaline rhizospheric soil of native grapevine grown at three locations. Ninety–five dominant, morphologically distinct rhizobacteria were purified, which belonged to 27 genera and 44 species. Gram-negative bacteria were dominating in the grapevine environment. Bacillus spp. and Pseudomonas spp. were common at both the acidic and alkaline soils. Among different groups, Gammaproteobacteria, Firmicutes and Actinobacteria comprised the largest groups contributing to about 42.1, 33.7 and 9.5% of the total N2-fixing isolates, respectively. The cultivated bacterial community from rhizosphere of native grapevine represented 27 different known bacterial genera represented by Pseudomonas, Bacillus, Brevibacillus, Stenotrophomonas, and Paenibacillus as as the predominant genera. Of the 95 nitrogen fixing isolates, 12 were able to fixe nitrogen and solubilize phosphates, 12 were able to fixe nitrogen and produce siderophores, only five isolates were able to fix nitrogen, produce siderophores and solubilize phosphates at the same time. In addition, the majority of the isolates were able to grow under high NaCl concentration. Our result showed that different geographical locations, soil pH, and vegetation type in the investigated sites resulted in the different bacterial population and bacterial type.

► We isolated and identified rhizobacteria from acidic and alkaline soil wild grape.
► We evaluated their N2-fixing, P-solubilising, siderophores-producing and other traits.
► rhizosphere wild grape surveyed first time as P-solubilizers, N2-fixers and others.
► 95 isolates fix N, 12 fixe N and solubilize P, 12 fixe N and produce siderophores.
► Some of isolates may be represent new nitrogen-fixing and P-solubilizing species.