Potential seed germination-enhancing plant growth-promoting rhizobacteria for restoration of Pinus chiapensis ecosystems

Rhizosphere soil samples of three Pinus chiapensis sites were analyzed for their physicochemical properties, soil bacteria isolated and screened in vitro for growth-promoting abilities. Nine isolates that showed promise were identified to five genera Dyella, Luteimonas, Enterobacter, Paraburkholderia and Bacillus based on the sequences of 16S rRNA gene. All the strains were isolated from non-disturbed stands. These bacteria significantly decreased germination time and increased sprout sizes. Indole acetic acid and gibberellin production and phosphate solubilisation were detected. Results indicate that these biochemicals could be essential for P. chiapensis distribution and suggest the possibility that PGPR inoculation on P. chiapensis seeds prior to planting could improve germination and possibly seedling development.