title: Pathogen-induced conditioning of the primary xylem vessels - a prerequisite for the formation of bacterial emboli by Pectobacterium atrosepticum.
abstract: Representatives of Pectobacterium genus are some of the most harmful phytopathogens in the world. In the present study, we have elucidated novel aspects of plant-Pectobacterium atrosepticum interactions. This bacterium was recently demonstrated to form specific 'multicellular' structures - bacterial emboli in the xylem vessels of infected plants. In our work, we showed that the process of formation of these structures includes the pathogen-induced reactions of the plant. The colonisation of the plant by P. atrosepticum is coupled with the release of a pectic polysaccharide, rhamnogalacturonan I, into the vessel lumen from the plant cell wall. This polysaccharide gives rise to a gel that serves as a matrix for bacterial emboli. P. atrosepticum-caused infection involves an increase of reactive oxygen species (ROS) levels in the vessels, creating the conditions for the scission of polysaccharides and modification of plant cell wall composition. Both the release of rhamnogalacturonan I and the increase in ROS precede colonisation of the vessels by bacteria and occur only in the primary xylem vessels, the same as the subsequent formation of bacterial emboli. Since the appearance of rhamnogalacturonan I and increase in ROS levels do not hamper the bacterial cells and form a basis for the assembly of bacterial emboli, these reactions may be regarded as part of the susceptible response of the plant. Bacterial emboli thus represent the products of host-pathogen integration, since the formation of these structures requires the action of both partners.
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.|Kazan Federal University, Kazan, Russia.
authors.forename: V Y
authors.initials: VY
authors.lastname: Gorshkov
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
authors.forename: A G
authors.initials: AG
authors.lastname: Daminova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
authors.forename: P V
authors.initials: PV
authors.lastname: Mikshina
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
authors.forename: O E
authors.initials: OE
authors.lastname: Petrova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
authors.forename: M V
authors.initials: MV
authors.lastname: Ageeva
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.|Kazan Federal University, Kazan, Russia.
authors.forename: V V
authors.initials: VV
authors.lastname: Salnikov
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
authors.forename: T A
authors.initials: TA
authors.lastname: Gorshkova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.|Kazan Federal University, Kazan, Russia.
authors.forename: Y V
authors.initials: YV
authors.lastname: Gogolev
mesh_terms: D002473:Cell Wall / Q000378:metabolism / Q000648:ultrastructure; D054884:Host-Pathogen Interactions; D010368:Pectins / Q000032:analysis / Q000378:metabolism*; D044043:Pectobacterium / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D011134:Polysaccharides / Q000032:analysis / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure; D052584:Xylem / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure
chemical_list: D011134:Polysaccharides; D017382:Reactive Oxygen Species; C042491:rhamnogalacturonan I; D010368:Pectins
keywords: Bacterial emboli; Pectobacterium atrosepticum; biofilm; plant cell wall; plant-microbe interaction; reactive oxygen species; rhamnogalacturonan I