Plant Growth-Promoting Rhizobacteria Enhance Sweet Cherry Root System Development Through the Production of Volatile...

Sweet cherry (Prunus avium L.), as a high-economic-value fruit with both nutritional and health functions, faces severely constrained plant growth due to underdeveloped root systems and suboptimal orchard site conditions. Plant growth-promoting rhizobacteria (PGPR) demonstrate application potential in regulating plant development and improving soil structure through the release of volatile organic compounds (VOCs). This study systematically evaluated the effects of VOCs from three PGPR strains-Pantoea ananatis D1-28, Burkholderia sp. D4-24, and Burkholderia territorii D4-36-on cherry root development and rhizosphere microbial communities. The results indicate that when D1-28 and D4-24 strains were at 10³ cfu·mL^-1 and D4-36 was at 10⁵ CFU·mL^-1, their VOCs exhibited optimal growth-promoting effects. Compared with the control group, significant improvements were observed in cherry seedling parameters, including plant height, total biomass, root length, root surface area, and root volume. The VOCs from these strains synergistically promoted plant growth by regulating auxin synthesis pathways in cherry roots while enhancing the relative abundance of beneficial rhizosphere microorganisms. This study establishes the strain-concentration-effect relationship, providing a theoretical foundation to optimize soil microbial environments and promote cherry root development using PGPR.