Genetic analysis of glyphosate tolerance in Halomonas variabilis strain HTG7
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- Liu, Z., Lu, W., Chen, M. et al. World J Microbiol Biotechnol (2006) 22: 681. doi:10.1007/s11274-005-9090-4
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A highly glyphosate-tolerant bacterium strain HTG7 was isolated from glyphosate-polluted soil in north China, and identified as Halomonas variabilis. It was a Gram-negative motile rod giving convex colony. The strain HTG7 could tolerate up to 900 mM glyphosate in minimal medium. The 16S rDNA sequence was amplified by PCR using universal primers. The region essential for glyphosate tolerance was localized to a 3.5-kb fragment from a cosmid library of HTG7. The DNA fragment consisted of one complete open reading frame (ORF) and one partial ORF. The partial ORF was homologous to prephenate dehydrogenase of Pseudomonasaeruginosa PA01. The complete ORF contained the tyrA and aroA genes. Only the 1.35-kb aroA encoding EPSP synthase conferred glyphosate tolerance, and complemented with E. coliaroA mutant ER2799. E. coli JM109 harboring aroA grew well in Mops supplemented with 80 mM glyphosate.