Control of Magnaporthe oryzae and Rice Growth Promotion by Bacillus subtilis JN005

It is quite important to develop the microorganism resources with biocontrol capacity for rice blast. This study evaluated Bacillus subtilis JN005 for growth promotion and biocontrol efficacy against Magnaporthe oryzae. Results showed that rice seeds treated with 1x10(7) cfu/mL suspension of B. subtilis JN005 had 16% germination energy, 14% germination rate, 15% germination index, and 270% vigor index compared to those treated with sterile water (control). In pot experiments, the JN005 strain-treated rice plants exhibited notable increase in plant height, root length, stem circumference, and fresh weight, as well as higher concentration of chlorophyll a, chlorophyll b, and total chlorophyll in rice leaves. Rice leaves inoculated with the JN005 strain resulted in increased activities of defense-related enzymes, including peroxidase (POD), phenylalanine ammonialyase (PAL), superoxide dismutase (SOD), and catalase (CAT) compared to the water and the M. oryzae-inoculated treatments. In vitro inoculated rice leaves with 1x10(7) cfu/mL bacterial suspension compared to sterile water or control treatment exhibited lower disease incidence in the curative and preventive groups by 79% and 76%, respectively. Field experiment showed that after spraying with 1x10(7) cfu/mL bacterial suspension, efficacy rates on controlling rice blast on plants were (56.82 +/- 1.12)% and (58.39 +/- 3.05)% at seedling and maturity stages, respectively, and that rice production yield was (524.40 +/- 17.88) g/m(2). Therefore, B. subtilis JN005 could be a promising biological control agent for rice blast, thereby warranting further investigation of its efficacy.

Automated summary

Bacillus subtilis JN005 shows growth promotion and biocontrol efficacy against rice blast, improving germination and growth of rice seeds, enhancing defense enzyme activities in rice leaves, and reducing disease incidence by 79% and 76% in curative and preventive treatments, respectively. Additionally, field experiments demonstrate that spraying with JN005 suspension at 1x10(7) cfu/mL can effectively control rice blast and increase rice production yield.