The -Regulated Membrane Protein Gene Is Involved in Copper Homeostasis and Gene Expression in subsp. .

subsp. () is the major causal agent of citrus canker disease. The gene, which encodes a conserved membrane protein in , is required for virulence during infection. However, the molecular events mediated by remain unclear. In this study, we reported that gene is positively regulated by two component regulatory system and required for type III secretion system function. A non-polar deletion mutant of the gene resulted in a Hrp minus phenotype in plants and reduced copper homeostasis. Real-time PCR experiments indicated that gene is induced by copper ions. The expression levels of representative genes from four operons, including , and , were reduced in mutant, indicating that is involved gene expression.