|Chee Sanford, Joanne|
Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/16/2007
Publication Date: 5/21/2007
Citation: Sanford, R.A., Chee Sanford, J.C., Loeffler, F.E. 2007. Reductive Dehalogenation of Herbicides by Anaeromyxobacter dehalogenans [abstract]. American Society for Microbiology Annual Meeting. Paper No. Q-162. Interpretive Summary:
Technical Abstract: Members of the genus Anaeromyxobacter are well known for their versatile respiratory capabilities, including reductive dehalogenation of phenolic compounds. The widespread distribution of Anaeromyxobacter spp. in the environment suggests their potential significance in biogeochemical cycling including chloroorganic compound transformation. Little information is available on anaerobic degradation of herbicides, many of which are structural analogs of halogenated phenolic compounds. In this study, four strains of A. dehalogenans were tested for their abilities to degrade bromoxynil, atrazine, dicamba, and 2,4-D, herbicides commonly use in commercial corn and soybean crops. A. dehalogenans strain 2CP-3 was able to reductively debrominate 50 µM bromoxynil, with transient formation of a monobrominated metabolite and stoichiometric accumulation of cyanophenol, using acetate as the electron donor. Bromoxynil was similarly degraded by related strains R, K, and 2CP-C, albeit conversion occurred at slower rates and was incomplete. Atrazine, 2,4-D, and dicamba were not degraded after a one month incubation period by the pure cultures. To estimate the distribution of Anaeromyxobacter spp in agricultural soils, 257 soil samples from a network of midwestern U.S. corn and soybean fields were collected. Anaeromyxobacter 16S rRNA gene sequences were detected in all samples with a genus-specific primer pair, and amplification with strain 2CP-C-specific primer pair yielded amplicons with 87% of the samples. The presence of Anaeromyxobacter in the majority of soils tested and the ability of several A. dehalogenans strains to reductively dehalogenate bromoxynil suggests the that these microorganisms contribute to herbicide fate under anaerobic conditions.