title: Virulence Factors of Erwinia amylovora: A Review.
abstract: Erwinia amylovora, a Gram negative bacteria of the Enterobacteriaceae family, is the causal agent of fire blight, a devastating plant disease affecting a wide range of host species within Rosaceae and a major global threat to commercial apple and pear production. Among the limited number of control options currently available, prophylactic application of antibiotics during the bloom period appears the most effective. Pathogen cells enter plants through the nectarthodes of flowers and other natural openings, such as wounds, and are capable of rapid movement within plants and the establishment of systemic infections. Many virulence determinants of E. amylovora have been characterized, including the Type III secretion system (T3SS), the exopolysaccharide (EPS) amylovoran, biofilm formation, and motility. To successfully establish an infection, E. amylovora uses a complex regulatory network to sense the relevant environmental signals and coordinate the expression of early and late stage virulence factors involving two component signal transduction systems, bis-(3'-5')-cyclic di-GMP (c-di-GMP) and quorum sensing. The LPS biosynthetic gene cluster is one of the relatively few genetic differences observed between Rubus- and Spiraeoideae-infecting genotypes of E. amylovora. Other differential factors, such as the presence and composition of an integrative conjugative element associated with the Hrp T3SS (hrp genes encoding the T3SS apparatus), have been recently described. In the present review, we present the recent findings on virulence factors research, focusing on their role in bacterial pathogenesis and indicating other virulence factors that deserve future research to characterize them.
authors.affiliation: Departament de Microbiologia i Parasiologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. npique@ub.edu.
authors.forename: Núria
authors.initials: N
authors.lastname: Piqué
authors.affiliation: Departament de Microbiologia i Parasiologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. davidminyana@ub.edu.
authors.forename: David
authors.initials: D
authors.lastname: Miñana-Galbis
authors.affiliation: Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08071 Barcelona, Spain. smerino@ub.edu.
authors.forename: Susana
authors.initials: S
authors.lastname: Merino
authors.affiliation: Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08071 Barcelona, Spain. jtomas@ub.edu.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Tomás
mesh_terms: D058947:Bacterial Secretion Systems / Q000235:genetics / Q000378:metabolism; D044084:Erwinia amylovora / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D053038:Quorum Sensing; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D058947:Bacterial Secretion Systems; D037521:Virulence Factors
keywords: Erwinia amylovora; amylovoran; biofilms; exopolysaccharide; fire blight; motility; plant pathogenesis; quorum sensing; type III secretion system; virulence factors