Selection of Streptomyces viridochromogenes DSM 4112 using phosphinothricyl-alanyl-alanine (PTT) results in PTT-resistant selectants. Subjecting the total DNA of these selectants to cutting with Bam HI, cloning of a 4.0 kb fragment and selection for PTT resistance result in the DNA fragment which harbours the phosphinothricin (PTC)-resistance gene. The latter is suitable for producing PTC-resistant plants, and as resistance marker and for the selective N-acetylation of the L form of racemic PTC. <IMAGE>
