2017 ASHS Annual Conference

The aim of the current study is to describe the role and mechanism of Bacillus amyloliquefaciens Y1 against root knot nematode, Meloidogyne incognita, under in vitro and in vivo conditions. Initially, exposure of bacterial culture filtrate and butanol crude extract of Y1 to M. incognita showed significant inhibition on egg hatch and caused mortality of second-stage juveniles (J2). The hatch inhibition and J2 mortality increased with increase in the concentration of those. The dipeptide, cyclo(D-Pro-L-Leu) having the nematicidal activity was identified for the first time in B. amyloliquefaciens strain culture supernatant using chromatographic techniques and nuclear magnetic resonance (NMR, ¹H, ¹³C, H-H COSY, HSQC and HMBC). Exposure of M. incognita to various concentrations of cyclo(D-Pro-L-Leu) significantly reduced egg hatch and caused substantial mortality of J2. All tomato plants were infested with M. incognita and then received Y1 culture, fertilizer medium (F), F+chemical nematacide, or chemical nematacide. The results from pot experiments demonstrated potential antagonistic effect of B. amyloliquefaciens Y1 against M. incognita by reducing the number of galls and eggs per root of tomato plant and number of J2 in the soil. Besides, the investigation on the growth parameters such as the shoot length, fresh and dry weights of the tomato plants increased evidently in the strain Y1 treated plants compared to control. Therefore, our study demonstrated the ability B. amyloliquefaciens Y1 as a biocontrol agent against M. incognita as well as plant growth promoter for tomato.