In Vitro Evaluation of Seed Bacterisation for Suppressing Bacterial Panicle Blight and Enhancing Growth in Rice

Abstract

Rice production faces significant challenges due to poor seed quality, low germination rates, and major diseases such as bacterial panicle blight caused by Burkholderia glumae. These factors threaten crop yield and sustainability, necessitating alternative solutions to enhance seed health and disease resistance. Seed bacterisation with plant growth-promoting rhizobacteria (PGPR) is a promising approach to improve rice growth, vigour, and stress tolerance. This study evaluated the effects of seed bacterisation using five bacterial isolates (B1-2-4, B1-2-11, B2-5-2, 4-4-1, and 6-1) on germination, seed vigour, and disease suppression, while also screening their ability to promote plant growth and tolerate stress. Germination tests revealed a significant increase (p < 0.05) in seed germination for all treated seeds (99-100%) compared to the control (96%). The highest vigour index (p < 0.05) was recorded for isolate 6-1 (1272.65). Seed treatment significantly reduced disease incidence, with isolate 6-1 exhibiting the lowest incidence (62%). All tested isolates exhibited plant growth-promoting traits, including nitrogen fixation, phosphate, and potassium solubilization, except B1-2-11, which lacked potassium solubilisation ability. Additionally, all isolates produced ammonium and indole-3-acetic acid (IAA), with isolate 6-1 showing the highest IAA concentration (7.39 µg/mL). Stress tolerance tests revealed that all isolates survived in 0.5–5.0% NaCl and across a pH range of 3 to 9. These findings highlight the potential of bacterial seed treatment in enhancing germination, plant vigour, and disease resistance. Among the tested isolates, 6-1 demonstrated the strongest growth-promoting and stress tolerance capabilities, making it a promising candidate for sustainable rice production.