crown gall plasmidmedical dictionary

A plasmid, or type of circular DNA, found in the bacteria Agrobacterium tumefaciens which infects dicot plants. Part of the plasmid inserts itself into the plant genome and causes tumours to form in the roots or in the stems nearest the roots. The plasmid has been used by geneticists, minus the tumour-causing parts, as a vector towards the genetic engineering of plants.

(09 Oct 1997)