A NONRADIOACTIVE DNA-PROBE FOR DETECTING DICYANDIAMIDE-DEGRADING SOILBACTERIA

Some soil bacteria are capable of degrading the nitrification inhibito r dicyandiamide (DCD). One of the most efficient isolates is strain EK 1 of Mycobacterium sp. for detecting this and closely related DCD-degr ading bacteria in soil we developed a non-radioactive DNA probe. A 1.7 -kb EK1 DNA fragment was selected from a genomic library and labelled with digoxigenin. The probe was highly specific for EK1 and closely re lated or identical species of soil bacteria. A method for direct detec tion of DNA from soil was developed. The sensitivity of this methodolo gy allowed detection of 2x10(3) EK1 cells g(-1) soil.