Heavy metal tolerant transgenic Brassica napus L. and Nicotiana tabacum L. plants.

A chimeric gene containing a cloned human metallothionein-II (MT-II) processed gene was introduced into Brassica napus and Nicotiana tabacum cells on a disarmed Ti-plasmid of Agrobacterium tumefaciens. Transformants expressed MT protein as a Mendelian trait and in a constitutive manner. Seeds from self-fertilized transgenic plants were germinated on media containing toxic levels of cadmium and scored for tolerance/ susceptibility to this heavy metal. The growth of root and shoot of transformed seedlings was unaffected by up to 100 μM CdCl2, whereas control seedlings showed severe inhibition of root and shoot growth and chlorosis of leaves. The results of these experiments indicate that agriculturally important plants such as B. napus can be genetically engineered for heavy metal tolerance/sequestration and eventually for partitioning of heavy metals in non-consumed plant tissues.