Diversity and metabolic potential of culturable n2-fixing and p-solubilising bacteria from rhizosphere of wild crops in Van lake basin -Turkey

Abstract

The diversity of phosphate solubilizing and nitrogen -fixing bacteria from rhizospheric soil samples of different plant species (native wild cereals, beet, stonecrops, onion, rose, raspberry, and 10 other plant genera) grown at four different locations in the Van Lake Basin, Turkey were investigated. A total of 169 rhizosperic soil samples were gathered from these plant species, and over 777 rhizoplane bacteria were haphazardly selected from agar -solidified trypticase soy broth and examined for fatty acid methyl ester (FAME) reports. As a result, 57 bacterial genera were recognised, which 64.8% gone to five genera viz., Bacillus (29.6%), Pseudomonas (9.8%), Stenotrophomonas (9.7%), Paenibacillus (5.7%), Micrococcus (5.1%), and Arthrobacter (4.9%). Approximately 56.8% of bacteria were found to be gram -positive (GPB), while 43.2% as gram -negative bacteria (GNB). In the of total GPB, 56.3% were N2 -fixing bacteria and 46.6% were P-solubilising bacteria, while in the case of GNB, 43.7% were N2 -fixing bacteria and 53.4% were P-solubilising bacteria. A total of 651 bacteria were isolated from the rhizospheric samples of the 20 plant genera, and subjected to further analysis. Of the 651 isolates, 542 were able to fix nitrogen, 279 were able to solubilize phosphates, and 247 isolates could fix both nitrogen and solubilize phosphates all at once. Bacillus, Pseudomonas, Stenotrophomonas, Paenibacillus, Micrococcus, Serratia, and Pantoea genera were the most prominent N2 -fixing and P-solubilising groups. Additionally, B. megaterium, B. atrophaeus, B. cereus, B. pumilus, B. licheniformis, B. subtilis, Pb. polymyxa, Pb. macerans, Pb. macquariensis, Bb. choshinensis, Ste. maltophilia, Ps. fluorescens, Ps. putida, Ps. stutzeri, Pn. agglomerans, Mic. luteus, Rco. erythropolis, Kocuria rosea, Csb. Meningosepticum, and Serratia fonticola were the mainly frequent P-solubilising and N2 -fixing species in the native rhizosphere soils of plants.