Microbial allies recruited by Bacillus subtilis JCK-1398 to defend pine trees against pinewood nematode.

Pine wilt disease (PWD) is a devastating disease caused by the pinewood nematode (Bursaphelenchus xylophilus). Its substantial ecological disruption harms global forestry and poses serious economic challenges. Although previous research has demonstrated that Bacillus subtilis JCK-1398 has the potential to induce systemic resistance in pine trees, the ecological mechanisms underlying its biocontrol efficacy remain underexplored. This study investigated how JCK-1398 treatment influences rhizosphere- and nematode-associated microbial communities to mitigate PWD. Metabarcoding analyses revealed that JCK-1398 treatment increased the abundance of beneficial microbial taxa (e.g., Nocardioides and Mesorhizobium) in the rhizosphere microbiome. Concurrently, nematode-associated microbial communities became dominated by Pantoea, a genus with known nematicidal properties. Isolation and characterization of Pantoea dispersa BC11 confirmed that it significantly limits nematode viability. These findings highlight the multifaceted defense that JCK-1398 offers, not only inducing systemic resistance, but also orchestrating beneficial microbiome dynamics. This study emphasizes the potential of manipulating a microbial holobiont for eco-friendly and sustainable disease management. The ability of JCK-1398 to recruit and enhance microbial allies offers a novel framework for developing biocontrol agents, with implications for managing PWD and other plant-pathogen systems.