Isolation and Identification of a Glyphosate-resistant Yeasty Strain (ZM-1) and Its Optimal Growth and Degradation Traits

Abstract:

Using glyphosate as the sole selective pressure, a yeast strain ZM-1 was isolated by enrichment-domestication culture technique from cultivated soils in the suburb around Fuzhou, PR China. The strain was identified as Rhodotorula mucilaginosa based on its physiological, biochemical and 26S rDNA D1/D2 domain sequences analysis. Strain ZM-1 grew with glyphosate as sole carbon and nitrogen source. The maximum glyphosate tolerant concentration for ZM-1 was 50 g/L. Strain ZM-1 was cultivated for 7 d under the conditions that glyphosate concentration 1 g/L, temperature 30°C, and rotation speed 150 r/min with 85.38% glyphosate-degraded rate. With the basal salts medium, the optimal conditions for growth and glyphosate-degraded rate for the strain were as follow: initial glyphosate concentration 1 g/L, inoculating dose 4% (V/V), temperature 30°C, pH value 5.5-6.0 and medium contents 50 mL/250 mL, respectively. Strain ZM-1 could play an important role in bioremediation of glyphosate-contaminated environment, and may be a potential resource in the study of glyphosate-resistant GMO plant.