title: PeBL1, a novel protein elicitor from Brevibacillus laterosporus strain A60, activates defense responses and systemic resistance in Nicotiana benthamiana.
abstract: We report the identification, characterization, and gene cloning of a novel protein elicitor (PeBL1) secreted from Brevibacillus laterosporus strain A60. Through a purification process consisting of ion-exchange chromatography and high-performance liquid chromatography (HPLC), we isolated a protein that was identified by electrospray ionization quadrupole time of flight tandem mass spectrometry (ESI-Q-TOF-MS-MS). The 351-bp PeBL1 gene produces a 12,833-Da protein with 116 amino acids that contains a 30-residue signal peptide. The PeBL1 protein was expressed in Escherichia coli. The recombinant protein can induce a typical hypersensitive response (HR) and systemic resistance in Nicotiana benthamiana, like the endogenous protein. PeBL1-treated N. benthamiana exhibited strong resistance to the infection of tobacco mosaic virus-green fluorescent protein (TMV-GFP) and Pseudomonas syringae pv. tabaci compared to control N. benthamiana. In addition, PeBL1 triggered a cascade of events that resulted in defense responses in plants, including reactive oxygen species (ROS) production, extracellular-medium alkalization, phenolic-compound deposition, and expression of several defense-related genes. Real-time quantitative-PCR analysis indicated that the known defense-related genes PR-1, PR-5, PDF1.2, NPR1, and PAL were upregulated to varying degrees by PeBL1. This research not only provides insights into the mechanism by which beneficial bacteria activate plant systemic resistance, but also sheds new light on a novel strategy for biocontrol using strain A60.
authors: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors: Haoqian
authors: H
authors: Wang
authors: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors: Xiufen
authors: X
authors: Yang
authors: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors: Lihua
authors: L
authors: Guo
authors: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China.
authors: Hongmei
authors: H
authors: Zeng
authors: State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China qiudewen@caas.cn.
authors: Dewen
authors: D
authors: Qiu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D058675:Brevibacillus / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000276:immunology / Q000382:microbiology*; D014027:Tobacco Mosaic Virus / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D017382:Reactive Oxygen Species