Panatda SaenkhamSupa UtamapongchaiPaiboon VattanaviboonSkorn MongkolsukChulabhorn Research InstituteChulabhorn Graduate InstituteMahidol University2018-07-122018-07-122008-12-01FEMS Microbiology Letters. Vol.289, No.1 (2008), 97-10315746968037810972-s2.0-54249100988https://repository.li.mahidol.ac.th/handle/20.500.14594/18816Singlet oxygen is a highly reactive form of molecular oxygen that is harmful to biological systems. Here, the role of three iron-containing superoxide dismutase (sodB) genes is clearly shown in protecting Agrobacterium tumefaciens against singlet oxygen toxicity. A sodBI mutant was more sensitive to singlet oxygen than both wild-type bacteria and a double sodBII-sodBIII mutant strain. Moreover, a sodBI-sodBII double mutant had higher sensitivity to singlet oxygen than a single sodBI mutant, although the double mutant was comparable to a sodB null mutant. High-level expression of sodBI and sodBII fully complemented the singlet oxygen hypersensitivity phenotype of the sodB null mutant, while high-level expression of sodBIII encoding a periplasmic SOD only partially restored the phenotype. Taken together, our data suggest that SodBI and SodBII have novel protective roles against singlet oxygen toxicity through unknown mechanisms. © 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyImmunology and MicrobiologyArticleSCOPUS10.1111/j.1574-6968.2008.01382.x