Rice blast, caused by the fungal pathogen Pyricularia oryzae, remains one of the most destructive diseases threatening global rice production. Although the deployment of resistant cultivars is widely regarded as the most effective and sustainable control strategy, resistance based solely on host genetics often has limited durability due to the rapid adaptation of the pathogen. Increasing evidence suggests that plant-associated microbial communities contribute to host health and disease resistance, yet the role of seed-associated microbiota in shaping rice blast resistance remains insufficiently understood. In this study, we investigated seed endophytic bacterial communities across multiple indica–japonica hybrid rice varieties from the Yongyou series that exhibit contrasting levels of resistance to rice blast. By integrating amplicon sequencing, we identified distinct seed bacterial assemblages associated with blast-resistant and blast-susceptible varieties were identified. Notably, the microbial communities in blast-resistant varieties exhibited significantly higher Shannon index, with a median value of 3.478 compared to 2.654 in susceptible varieties (p < 0.001), indicating a greater diversity and more balanced community structure compared to those in susceptible varieties. Several bacterial taxa consistently enriched in resistant varieties showed negative ecological associations with P. oryzae, both at the local scale and across publicly available global metagenomic datasets. These findings indicate that seed endophytic bacterial communities are non-randomly structured in relation to host resistance phenotypes and may contribute to rice blast resistance through persistent ecological interactions with the pathogen. This work highlights the potential importance of seed-associated microbiota as intrinsic components of varietal resistance and provides a microbial perspective for improving durable disease resistance in rice breeding programs.
Chen et al. (2026) studied this question.