Degradation of CP4-EPSPS with a Psychrophilic Bacterium Stenotrophomonas maltophilia 780

Abstract

CP4-EPSPS (Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase) protein showed remarkable thermostability and was highly resistant to proteases, such as trypsin. In order to eliminate the pollution of CP4-EPSPS from the accumulated straws to the surrounding environment during the winter, the present study investigated the extracellular proteases of 21 psy-chrophilic strains isolated from the south polar region. The results indicated that Stenotrophomonas maltophilia 780 was able to degrade CP4-EPSPS at 18◦ C efficiently. Further study indicated that it was able to grow in the extract of Roundup Ready soybean at 18◦ C, with CP4-EPSPS degraded to an undetectable level within 72 h. The extracellular proteases of Stenotrophomonas maltophilia 780 are thermo-sensitive, with an optimal temperature of 65◦ C. The genomic sequencing result indicated that this strain had more than a hundred putative protease and peptidase coding genes, which may explain its high capability in decomposing CP4-EPSPS.