Agrobacterium tumefaciens iron superoxide dismutases have protective roles against singlet oxygen toxicity generated from illuminated Rose Bengal.
Singlet 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.
Saenkham
Panatda
P
Department of Biotechnology, Faculty of Science, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand.
Utamapongchai
Supa
S
Vattanaviboon
Paiboon
P
Mongkolsuk
Skorn
S
D016960:Agrobacterium tumefaciens / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008027:Light; D009154:Mutation; D012395:Rose Bengal / Q000378:metabolism*; D026082:Singlet Oxygen / Q000378:metabolism / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
D003470:Culture Media; D007527:Isoenzymes; D026082:Singlet Oxygen; D012395:Rose Bengal; D013482:Superoxide Dismutase