Isolation of Beneficial Bacteria from Wheat Plant Rhizosphere and Determination of PGP (Plant Growth Promoting) Properties

Wheat, an important food and industrial product, is one of the most widely grown plants in the world. Environmentally friendly alternative methods are needed to increase plant productivity. Plant growth-promoting rhizobacteria (PGPR) directly or indirectly promote plant growth and production by actively colonizing plant roots. In the current study, 49 isolates were obtained from rhizospheric soil samples of wheat fields in 6 districts of Kırşehir (Akpınar, Boztepe, Kaman, Mucur, Akçakent, Çiçekdağı) in May 2019 and the isolates were identified biochemically and by MALDI-TOF mass spectrometry. The MALDI-TOF MS results showed that 49 isolates from 14 distinct genera could be identified. Among the isolates, Bacillus, Pseudomonas, and Pseudarthrobacter ranked first through third. Plant growth promoting properties of these isolates (inorganic phosphate solubilisation, siderophore production, nitrogen fixation, HCN (Hydrogen cyanide) production, IAA (Indole-3-acetic acid) production) were screened. Among 49 isolates, 4 isolates (MH-50-6, MH-50-7, MH-60-1, and MH-60-3) dissolved inorganic phosphate, and 13 isolates (MH-28-1, MH-34-3, MH-34-8, MH-39-1, MH-39-3, MH-39-7, MH-50-8, MH-55-3, MH-55-7, MH-55-9, MH-60-1, MH-60-3, MH-60-5) nitrogen fixed, on the other hand, 9 isolates (MH-34-5, MH-34-8, MH-39-5, MH-50-6, MH-50-7, MH-50-8, MH-55-6, MH-60-1, MH-60-3) produced siderophores, 8 isolates (MH-28-1, MH-34-2, MH-34-4, MH-34-5, MH-39-1, MH-55-3, MH-60-2, MH-60-5) produced HCN, while 4 isolates (MH-34-8, MH-50-4, MH-50-8, MH-55-9) was determined to produce IAA. In conclusion, indigenous PGPR (Pseudarthrobacter oxydans MH-34-8, Pseudomonas jessenii MH-50-8, Arthrobacter crystallopoietes MH-60-1, Aromatoleum evansii MH-60-3) isolates gave positive results for at least 3 plant growth-promoting properties. The present study is the first study on growth-promoting plants isolated from wheat in Kırşehir (Turkey). This study will illuminate the preparation of effective microbial fertilizer with local bacterial species that spread in the region and the availability of local culture collections.