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Poster: Biology & Disease Mgmt: Biological Control


Putative biocontrol mechanisms of rice bacterial blight by Bacillus subtilis TKS1-1
T. HUANG (1), Y. Chen (1), Y. Jan (1), Y. Yeh (1), D. Tzeng (1) (1) Department of Plant Pathology, National Chung Hsing University, Taiwan

Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae is one of the devastating diseases of rice plant. The main objectives of the research are to investigate the potential of using Bacillus subtilis TKS1-1 as a control agent of rice bacterial blight and the possible mechanisms involved in disease control. B. subtilis TKS1-1 showed antagonistic activity against X. oryzae WF6. Application of B. subtilis TKS1-1 at the time of or prior to inoculation with X. oryzae WF6 was found to suppress rice bacterial blight. Additionally, the lesion length of leaf blight was less by drenching application with B. subtilis TKS1-1 compared to the water control. Spray-application of B. subtilis TKS1-1 was shown to increase the expression of several plant defense-related genes including PR1a, PAL, NPR1, and WRKY45 at 16 hours post application compared to the water control. Furthermore, drenching application of strain TKS1-1 7 days prior to inoculation of the pathogen was found to increase the activity of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase at 48 hours post-inoculation in comparison with the water treatment. Application of B. subtilis TKS1-1 on rice cultivar TNG67 showed significant promotion of plant growth. The findings suggested that B. subtilis TKS1-1 exhibited efficacy in suppression of rice bacterial blight and in growth promotion. The biocontrol potential is partly attributed to the induction of plant defense response by B. subtilis TKS1-1.