To demonstrate the expression profiling of Xanthomonas oryzae pv.oryzae(Xoo) in vitro and in planta,DNA microarrays of 371 genes potentially associated with pathogenicity and virulence were used to compare the transcriptional level alteration of the wild-type strain PXO99A and gene deletion mutants ΔgacAxoo and ΔfleQxoo of Xoo grown in the rich medium NBY vs.hrp-inducing minimal medium XOM2 or leaf tissues of rice.Results indicated that 17 and 38 genes of PXO99A were differentially expressed in XOM2 and the leaf tissues of rice relative to NBY,respectively.Twenty-eight genes of ΔgacAxoo grown in XOM2 and 12 genes of ΔfleQxoo in NBY were differentially expressed relative to PXO99A.The identification of differentially-expressed genes,GacAxoo-and FleQxoo-regulons and novel candidate genes of Xoo strains would provide us the target genes for further functional analysis in pathogenesis of Xoo.
