title: Asymmetric chromosome segregation in Xanthomonas citri ssp. citri.
abstract: This study was intended to characterize the chromosome segregation process of Xanthomonas citri ssp. citri (Xac) by investigating the functionality of the ParB factor encoded on its chromosome, and its requirement for cell viability and virulence. Using TAP tagging we show that ParB is expressed in Xac. Disruption of parB increased the cell doubling time and precluded the ability of Xac to colonize the host citrus. Moreover, Xac mutant cells expressing only truncated forms of ParB exhibited the classical phenotype of aberrant chromosome organization, and seemed affected in cell division judged by their reduced growth rate and the propensity to form filaments. The ParB-GFP localization pattern in Xac was suggestive of an asymmetric mode of replicon partitioning, which together with the filamentation phenotype support the idea that Xac may control septum placement using mechanisms probably analogous to Caulobacter crescentus, and perhaps Vibrio cholerae, and Corynebacterium glutamicum. Xac exhibits asymmetric chromosome segregation, and the perturbation of this process leads to an inability to colonize the host plant.
authors: Depto. de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, Rodovia Araraquara/Jaú Km 1, CP 502, Araraquara, São Paulo, 14801-902, Brazil.
authors: Amanda P
authors: AP
authors: Ucci
authors: Paula M M
authors: PM
authors: Martins
authors: Ivy F
authors: IF
authors: Lau
authors: Maurício
authors: M
authors: Bacci
authors: José
authors: J
authors: Belasque
authors: Henrique
authors: H
authors: Ferreira
mesh_terms: D002455:Cell Division; D002470:Cell Survival; D020090:Chromosome Segregation; D002957:Citrus / Q000382:microbiology; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005800:Genes, Fungal; D010641:Phenotype; D010935:Plant Diseases; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000737:chemistry; D014774:Virulence; D014974:Xanthomonas / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins
keywords: Cell division arrest; chromosome segregation; citrus canker.