title: Bacillus cereus strain S2 shows high nematicidal activity against Meloidogyne incognita by producing sphingosine.
abstract: Plant-parasitic nematodes cause serious crop losses worldwidely. This study intended to discover the antagonistic mechanism of Bacillus cereus strain S2 against Meloidogyne incognita. Treatment with B. cereus strain S2 resulted in a mortality of 77.89% to Caenorhabditis elegans (a model organism) and 90.96% to M. incognita. In pot experiment, control efficiency of B. cereus S2 culture or supernatants were 81.36% and 67.42% towards M. incognita, respectively. In field experiment, control efficiency was 58.97% towards M. incognita. Nematicidal substances were isolated from culture supernatant of B. cereus S2 by polarity gradient extraction, silica gel column chromatography and HPLC. Two nematicidal compounds were identified as C16 sphingosine and phytosphingosine by LC-MS. The median lethal concentration of sphingosine was determined as 0.64 μg/ml. Sphingosine could obviously inhibit reproduction of C. elegans, with an inhibition rate of 42.72% for 24 h. After treatment with sphingosine, ROS was induced in intestinal tract, and genital area disappeared in nematode. Furthermore, B. cereus S2 could induce systemic resistance in tomato, and enhance activity of defense-related enzymes for biocontrol of M. incognita. This study demonstrates the nematicidal activity of B. cereus and its product sphingosine, as well provides a possibility for biocontrol of M. incognita.
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Gao
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Gaofu
authors.initials: G
authors.lastname: Qi
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Rong
authors.initials: R
authors.lastname: Yin
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Hongchun
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Chenggang
authors.initials: C
authors.lastname: Li
authors.affiliation: Huazhong Agricultural University, College of Life Science and Technology, Wuhan, 430070, PR China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000818:Animals; D001409:Bacillus cereus; D061046:Biological Control Agents; D017173:Caenorhabditis elegans / Q000382:microbiology*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D018551:Solanum lycopersicum / Q000469:parasitology*; D013058:Mass Spectrometry; D017382:Reactive Oxygen Species / Q000737:chemistry; D013110:Sphingosine / Q000031:analogs & derivatives / Q000737:chemistry*; D014431:Tylenchoidea / Q000382:microbiology*
chemical_list: D061046:Biological Control Agents; D017382:Reactive Oxygen Species; C012491:phytosphingosine; D013110:Sphingosine; C005682:safingol