Microarray Analysis of bacterial blight resistance 1 mutant rice infected with Xanthomonas oryzae pv. oryzae

We analyzed the transcriptional profile of the Xoo infected bbr1 mutant using a commercial rice gene chip containing 51,279 transcripts. Microarray revealed 92 genes with increased levels of expression and 22 genes with decreased levels of expression in bbr1. Some of the differentially expressed genes were validated by qRT-PCR. Higher expression of defense-related genes and AP2 domain containing transcription factors along with lower expression of reactive oxygen scavenging enzymes may be responsible for defense signaling in the bbr1 upon Xoo infection. The putative target genes of AP2 domain containing transcription factors also showed differential gene expression during Xoo infection, some of which encoded bacterial pathogen resistance-related protein. Induction of AP2 domain containing transcription factors along with up-regulation of their putative target genes during Xoo infection may inhibit pathogen spread in the bbr1. This observation supports the hypothesis that AP2 domain containing transcription factors is involved in the regulation of differentially expressed genes in bbr1.