title: Coupling two mercury resistance genes in Eastern cottonwood enhances the processing of organomercury.
abstract: Eastern cottonwood (Populus deltoides Bartr. ex Marsh.) trees were engineered to express merA (mercuric ion reductase) and merB (organomercury lyase) transgenes in order to be used for the phytoremediation of mercury-contaminated soils. Earlier studies with Arabidopsis thaliana and Nicotiana tabacum showed that this gene combination resulted in more efficient detoxification of organomercurial compounds than did merB alone, but neither species is optimal for long-term field applications. Leaf discs from in vitro-grown merA, nptII (neomycin phosphotransferase) transgenic cottonwood plantlets were inoculated with Agrobacterium tumefaciens strain C58 carrying the merB and hygromycin resistance (hptII) genes. Polymerase chain reaction of shoots regenerated from the leaf discs under selection indicated an overall transformation frequency of 20%. Western blotting of leaves showed that MerA and MerB proteins were produced. In vitro-grown merA/merB plants were highly resistant to phenylmercuric acetate, and detoxified organic mercury compounds two to three times more rapidly than did controls, as shown by mercury volatilization assay. This indicates that these cottonwood trees are reasonable candidates for the remediation of organomercury-contaminated sites.
authors.affiliation: Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA. satu.lyyra@iki.fi
authors.forename: Satu
authors.initials: S
authors.lastname: Lyyra
authors.forename: Richard B
authors.initials: RB
authors.lastname: Meagher
authors.forename: Tehryung
authors.initials: T
authors.lastname: Kim
authors.forename: Andrew
authors.initials: A
authors.lastname: Heaton
authors.forename: Paul
authors.initials: P
authors.lastname: Montello
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Balish
authors.forename: Scott A
authors.initials: SA
authors.lastname: Merkle
mesh_terms: D001673:Biodegradation, Environmental; D015153:Blotting, Western; D002934:Cinnamates / Q000494:pharmacology; D004351:Drug Resistance; D006921:Hygromycin B / Q000031:analogs & derivatives / Q000494:pharmacology; D008190:Lyases / Q000235:genetics*; D009941:Organomercury Compounds / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics*; D010662:Phenylmercuric Acetate / Q000378:metabolism* / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D032107:Populus / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D012231:Rhizobium / Q000235:genetics; D014170:Transformation, Genetic; D019076:Transgenes
chemical_list: D002934:Cinnamates; D009941:Organomercury Compounds; D006921:Hygromycin B; C026273:hygromycin A; D010088:Oxidoreductases; C021551:mercuric reductase; D008190:Lyases; C050953:alkylmercury lyase; D010662:Phenylmercuric Acetate