PurposeTo test the resistance and growth-promoting activity of three strains of endophytic bacteria in sugarcane, and to determine the taxonomic status of superior strains, so as to provide theoretical basis and material for the subsequent research and development of biocontrol agents in sugarcane.
MethodsThree strains of Bacillus spp. P8, Q2 and P7 isolated from sugarcane cultivars Mintang 69-421 and Dianzhen 01-58 were used as research objects, and their broad-spectrum antibacterial activity and growth-promoting activity indexes were determined. By routine physiological and biochemical indicators and sequencing of 16S rRNA and GyrA, cluster analysis of the three strains was performed by MEGA software adjacency method.
ResultsThe effects of three strains on Fusarium moniliforme, Colletotrichum micotianae Averna, Rhizoctonia solani and F. graminearum, Exserohilum turcicum and Bipolaris maydis were investigated and all of them showed good inhibitory. The strain Q2 had the best inhibitory effect on B. maydis, the inhibitory rate was 81.60%, and the inhibitory rate on other pathogens was more than 61%. Its ferriphilin synthesis ability was stronger than P8 and P7; the utilization capacity of inorganic phosphorus was stronger than P8 and P7, and the soluble phosphorus content reached 166.95 mg/L. After three days of culture, cellulase activity of Q2 was 5.22 U/mL, with high activity and strong ability to produce cellulose. Q2 was identified as Bacillus subtilis.
ConclusionThe endophytic B. subtilis Q2 of sugarcane has good broad-spectrum antibacterial activity, and has high activities of ferritin, phosphor and cellulase, which has the potential for further development as a disease-resistant and growth-promoting biological agent.
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