BACILLUS AMYLOLIQUEFACIENS Lx-11, A POTENTIAL BIOCONTROL AGENT AGAINST RICE BACTERIAL LEAF STREAK

R.S. Zhang, Y.F. Liu, C.P. Luo, X.Y. Wang, Y.Z. Liu, J.Q. Qiao, J.J. Yu, Z.Y. Chen

Abstract


A strain of Bacillus amyloliquefaciens denoted Lx-11 was found to possess biocontrol activity against rice bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola. Lx-11 secreted three kinds of lipopeptides including surfactin, bacillomycin D and fengycin, which exhibted antibacterial activity against X. oryzae pv. oryzicola. The antibacterial activity could be associated with surfactin-lipopeptides, and was practically abolished in surfacin-deficient mutants. In addition, the defense-related genes PR-1a, PR-1b, NPR1 and PAL were concurrently expressed in the leaves of rice after treatment with Lx-11. Results suggest that Lx-11 triggers a systemic immunization activity. Lx-11 significantly reduced the incidence of BLS, control efficacy ranging from 60.2% to 70.6%, i.e. better than that afforded by bismerthlazol in field experiments. We conclude that B. amyloliquefaciens Lx-11 might be a promising biocontrol agent and should be further studied.

Keywords


Bacillus amyloliquefaciens;bacterial leaf streak;lipopeptides;defense-related genes;biological control

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DOI: http://dx.doi.org/10.4454/JPP.FA.2012.062

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