Roles of OxyRxoo, a transcriptional regulator of Xanthomonas oryzae pv. oryzae in regulation of detoxification of hydrogen peroxide

Abstract:

Abstract:[Objective] OxyRxoo is a homologue of OxyR from Xanthomonas oryzae pv. oryzae (Xoo),the pathogen of bacterial blight of rice. To elucidate the role of OxyRxoo in detoxification of hydrogen peroxide.[Methods] OxyRxoo was studied by gene cloning, sequencing, deletion, complement and phenotype analysis. [Result]Compared to those of the wild-type strain PXO99A, there was no difference in bacterial growth in vitro of △oxyRxoo, but △oxyRxoo is more sensitive to H2O2 with reduced catalase activity. In the presence of H2O2, the expression of catalase genes (ahpCxoo, catBxoo, katExoo and srpAxoo) was significantly down-regulated, while the expression of oxyRxoo was up-regulated in △oxyRxoo. [Conclusion] OxyRxoo functions as a transcription regulator in mediating and controlling H2O2 detoxification in Xoo.

Key words:Keywords: Xanthomonas oryzae pv. oryzae; OxyRxoo; H2O2 detoxification; catalase ; regulation