title: Identification of an Extracellular Endoglucanase That Is Required for Full Virulence in Xanthomonas citri subsp. citri.
abstract: Xanthomonas citri subsp. citri causes citrus canker disease, which is characterized by the formation of water-soaked lesions, white or yellow spongy pustules and brown corky canker. In this work, we report the contribution of extracellular endoglucanase to canker development during infection. The ectopic expression of nine putative cellulases in Escherichia coli indicated that two endoglucanases, BglC3 and EngXCA, show carboxymethyl cellulase activity. Both bglC3 and engXCA genes were transcribed in X. citri subsp. citri, however, only BglC3 protein was detected outside the cell in western blot analysis. The deletion of bglC3 gene resulted in complete loss of extracellular carboxymethyl cellulase activity and delayed the onset of canker symptoms in both infiltration- and wound-inoculation assays. When growing in plant tissue, the cell density of bglC3 mutant was lower than that of the wild type. Our data demonstrated that BglC3 is an extracellular endoglucanase required for the full virulence of X. citri subsp. citri.
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Yanjiao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Dongling
authors.initials: D
authors.lastname: Sun
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhuo
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Fan
authors.affiliation: Fujian Province Key Laboratory of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Huasong
authors.initials: H
authors.lastname: Zou
mesh_terms: D002480:Cellulase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002957:Citrus / Q000382:microbiology; D005110:Extracellular Space / Q000201:enzymology*; D017353:Gene Deletion; D006868:Hydrolysis; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D014774:Virulence; D014974:Xanthomonas / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*
chemical_list: D002480:Cellulase