Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri

cDNAs from sequenced kumquat libraries (ESTs) made from subtracted RNA populations, healthy vs. infected, were used to make this microarray. Of 2054 selected genes on a customized array, 317 were differentially expressed (P < 0.05) in Xcc challenged kumquat plants compared to mock-inoculated ones. This study identified components of the incompatible interaction such as reactive oxygen species (ROS) and programmed cell death (PCD). Common defence mechanisms and a number of resistance genes were also identified. In addition, there were a considerable number of differentially regulated genes that had no homologues in the databases. This could be an indication of either a specialized set of genes employed by kumquat in response to canker disease or new defence mechanisms in citrus.Functional categorization of kumquat Xcc-responsive genes revealed an enhanced defence-related metabolism as well as a number of resistant response-specific genes in the kumquat transcriptome in response to Xcc inoculation. Gene expression profile(s) were analyzed to assemble a comprehensive and inclusive image of the molecular interaction in the kumquat/Xcc system. This was done in order to elucidate molecular mechanisms associated with the development of the hypersensitive response phenotype in kumquat leaves. These data will be used to perform comparisons among citrus species to evaluate means to enhance the host immune responses against bacterial diseases.Citrus trees are susceptible to a number of diseases with different degrees of economic impact. One of the most severe in terms of economic losses is citrus canker disease (sometimes referred to as Asiatic citrus canker) caused by Xanthomonas citri subsp. citri, (synonym, Xanthomonas axonopodis pv. citri strain A; Xac-A). Xcc is a biotrophic bacterial phytopathogen that belongs to the genus Xanthomonas of the α-subdivision v within Proteobacteria. Susceptibility to citrus canker disease varies among citrus types and relatives, but most of