T-DNA tagging of a seed coat-specific cryptic promoter in tobacco.

T-DNA tagging with a promoterless beta-glucuronidase (GUS) gene generated a transgenic Nicotiana tabacum plant that expressed GUS activity only in developing seed coats. Cloning and deletion analysis of the GUS fusion revealed that the promoter responsible for seed coat specificity was located in the plant DNA proximal to the GUS gene. A 3.