Plant growth-promoting rhizobacteria for controlling rice diseases: What is known and what is next?

Rice ( Oryza sativa ) is a global staple threatened by diseases such as bacterial leaf blight ( Xanthomonas oryzae pv. oryzae ), sheath blight ( Rhizoctonia solani ), blast ( Magnaporthe oryzae ), and panicle blight ( Burkholderia glumae and B. gladioli ), which cause significant yield losses. Conventional agrochemical use has raised environmental and health concerns, prompting a shift toward sustainable alternatives. This review examines the role of plant growth-promoting rhizobacteria (PGPR) as promising biocontrol agents. PGPR enhance rice health and suppress pathogens through a variety of direct and indirect mechanisms. Direct actions include the production of antibiotics and lytic enzymes, competition for nutrients, and the synthesis of phytohormones and siderophores. Indirectly, PGPR activate induced systemic resistance (ISR), priming the plant's immune system via jasmonic acid (JA) and ethylene (ET) signaling pathways. While empirical studies confirm that PGPR can improve plant growth, enhance stress tolerance, and reduce disease severity, inconsistent field performance remains a major challenge. This variability is often due to complex strain-environment interactions, inconsistent root colonization, and the lack of robust formulations. To overcome these limitations, future research should focus on utilizing 'omics-based approaches to better understand PGPR-microbe-plant interactions. Additionally, there is a need to develop more stable biostimulant consortia and to fully integrate these biological agents into climate-smart agricultural systems. This review synthesizes current knowledge on PGPR-mediated disease management and highlights their potential to improve crop resilience and productivity while promoting eco-friendly farming practices. • PGPR suppress rice diseases through direct and indirect biocontrol mechanisms. • Induced systemic resistance is activated via jasmonic acid and ethylene pathways. • Field performance of PGPR remains inconsistent due to strain–environment interactions. • Omics-based approaches can uncover PGPR–microbe–plant interactions, enabling more effective applications. • Stable PGPR consortia can support eco-friendly and climate-smart rice production.