Mayuree FuangthongThichakorn JittawuttipokaRatiphorn WisitkamolAdisak RomsangJintana Duang-nkernPaiboon VattanaviboonSkorn MongkolsukChulabhorn Research InstituteChulabhorn Graduate InstituteMahidol UniversityCenter for Environmental Health2018-11-232018-11-232015-01-01Microbiological Research. Vol.170, (2015), 139-146094450132-s2.0-84930044441https://repository.li.mahidol.ac.th/handle/20.500.14594/36131© 2014 Elsevier GmbH. Iron-sulfur ([Fe-S]) cluster is an essential cofactor of proteins involved in various physiological processes including cellular defense against oxidative stress. In Xanthomonas campestris pv. campestris (Xcc), IscR plays a negative role in regulation of the transcription of [Fe-S] assembly genes, iscR-sufBCDS. The expression level of sufBCDS was up-regulated in an Xcc iscR mutant. In addition, the iscR promoter activity in an Xcc iscR mutant was also higher than the wild-type strain, indicating an autoregulatory circuit. Purified IscR was shown to bind at the iscR promoter region and three putative IscR binding sites were identified. The expression of iscR-suf operon was highly induced by oxidant treatments and iron limited conditions. The iscR mutant showed increased sensitivity toward hydrogen peroxide phenotype but, surprisingly, had hyper-resistant phenotype toward plumbagin compared to the wild-type strain. Most importantly, the iscR mutant was impaired in its ability to cause lesion on leaves of a compatible host plant, Chinese radish (Raphanus sativus). These results demonstrate that a transcription regulator gene, iscR, negatively regulates genes involved in [Fe-S] biosynthesis and plays a role in oxidative stress response and pathogenesis of Xcc.Mahidol UniversityImmunology and MicrobiologyArticleSCOPUS10.1016/j.micres.2014.08.004