Plant growth-promoting bacteria from Uzungöl forest stimulate rice growth via seed biopriming and root inoculation: isolation and functional characterization of potent PGPR strains from rhizosphere soils of different trees.

Introduction: Rhizobacteria naturally promote plant growth and offer a sustainable alternative to agrochemicals. In contrast to agroecosystems, forests host a diverse community of beneficial rhizobacteria that remains uncharacterized. Moreover, despite extensive research on rhizobacteria associated with cereal crops, such as rice, their efficacy in hydroponic rice cultivation still needs to be established. Methods: This study was aimed to isolate, characterize, and identify the potential plant growth-promoting rhizobacteria (PGPR) of different rhizospheres from Uzungöl forest situated in Trabzon, Turkey, and to evaluate their effects on the growth of rice through two distinct approaches: 1) seed biopriming to assess germination and 2) root inoculation to analyze seedling growth in a hydroponic system. Results: In total, 129 bacteria were isolated from eight different rhizospheres, and 109 exhibited indole-acetic acid (IAA) production. A strain of Discussion: These findings concluded that inoculation with forest-derived rhizobacteria is an effective strategy to enhance early growth of rice in soilless systems. Understanding the genetic basis of their growth promotion, coupled with large-scale field validation, could advance low-cost, sustainable rice cultivation with minimal reliance on agrochemicals.