Functional characterization of the general secretion pathway xpsD gene in Xanthomonas citri subsp. citri

Abstract:

[Objective] The purpose of this work was to identify the insertion site of mutant Mxac56-20 with reduced extracellular enzyme activities, and to characterize the function of the mutated gene. [Methods] The Tn5 flanking sequence was identified by using plasmid rescue method. After the complementary recombinant was constructed, the restorations of extracellular enzyme and pathogenicity on host plant were tested. [Results] Tn5 transposon was inserted in the general secretion pathway xpsD gene in Xanthomonas citri subsp. citri. The phenotypic alterations were restored when constitutively expressing xpsD gene in mutant Mxac56-20. [Conclusion] The mutagenesis of xpsD gene in X. citri subsp. citri led to the reductions in extracellular enzyme activities and pathogenicity on host plant. These collected data demonstrated that the general secretion pathway is required for full virulence on host plant by X. citri subsp. citri.

Key words:Xanthomonas citri subsp. citri, xpsD gene, Complementation, Extracellular enzyme, Pathogenicity