Isolation and molecular characterization of plant growth promoting bacteria from the rhizosphere of orchids in Turkey

The objective of the study was to isolate and identify bacteria having plant growth promoting rhizobacteria (PGPR) characteristics from the rhizosphere of wild orchids. Orchid plants belonging to the species of Anacamptis pyramidalis, Himantoglossum caprinum, Limodorum abortivum, Platanthera bifolia, Serapias vomeracea subsp. laxiflora, Spiranthes spiralis, Ophrys apifera, Ophrys sphegodes, Orchis coriophora, Orchis laxiflora, Orchis provincialis, Orchis tridentata from the Black Sea region (Samsun, Turkey). Rhizobacteria were isolated from the rhizosphere of orchids and assayed for phosphate solubilization, 1 aminocyclopropane-1-carboxylate (ACC) deaminase activity and indole-3-acetic acid (IAA) production. Out of 111 rhizobacteria, 65 solubilized phosphate, 32 had ACC deaminase activity, 83 produced IAA. Sixteen of the isolates showed all the traits. Comparing sequences of 16S rDNA against the database with BLAST, the most common genera were Bacillus, Paenibacillus, Pseudomonas, Acinetobacter, Agrobacterium and Stenotrophomonas. This is the first study to comprehensively evaluate the PGPR properties of strains isolated from wild orchid rhizosphere.