title: Attenuation and quantitation of virulence gene expression in quorum-quenched Dickeya chrysanthemi.
abstract: N-Acyl-homoserine lactones (AHLs)-dependent quorum sensing (QS) system(s) is recruited by the soft rot bacterium Dickeya chrysanthemi for coordinating its social activities such as secretion of plant cell wall-degrading enzymes, while the main signal molecule and quantity dependence of virulence to QS in this bacterium have not been clarified. To do this end, the involvement of AHLs in African violet leaves and potato tuber maceration; swarming motility; pectate lyase and polygalacturonase enzymes production and in planta expression of virulence genes including pelE, pehX and pemA by electroporating two quorum-quenching vectors. The expression of two types of AHL-lactonase expressing vector caused dramatic decrease in swarming motility, production of pectinolytic enzymes and macerating of plant tissues. The maximum ability of quenching of QS in repression of D. chrysanthemi virulence was assessed quantitatively by q-RT-PCR, as expression of pelE, pehX and pemA genes were decreased 90.5-92.18 % in quenched cells. We also showed that virulence and pathogenicity of this bacterium was under the control of DHL-dependent QS system and that the existence of second DHL operating system is probable for this bacterium. Thus, this signal molecule would be the key point for future research to design DHL-specific lactonase enzymes using bioinformatics methods.
authors: Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
authors: Saeed
authors: S
authors: Hosseinzadeh
authors: Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. shamsbakhsh@modares.ac.ir.
authors: Masoud
authors: http://orcid.org/0000-0003-2923-2668
authors: M
authors: Shams-Bakhsh
authors: Department of Genetics, Faculty of Basic Sciences, Tarbiat Modares University, P.O. Box 14155-4843, Tehran, Iran.
authors: Majid
authors: M
authors: Sadeghizadeh
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D016974:Dickeya chrysanthemi / Q000235:genetics* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D010935:Plant Diseases / Q000382:microbiology*; D011096:Polygalacturonase / Q000378:metabolism; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism; D053038:Quorum Sensing; D011198:Solanum tuberosum / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D054742:Acyl-Butyrolactones; D001426:Bacterial Proteins; D037521:Virulence Factors; D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase; C020579:gluconolactonase; D011096:Polygalacturonase; D011133:Polysaccharide-Lyases; C023911:pectate lyase
keywords: Gene expression; Quorum sensing; Soft rot; q-RT-PCR