DIFFERENTIAL UTILIZATION OF REGULATORY CIS-ELEMENTS FOR STRESS-INDUCED AND TISSUE-SPECIFIC ACTIVITY OF A FRENCH BEAN CHALCONE SYNTHASE PROMOTER

Expression of the French bean chalcone synthase (CHS) gene is induced in response to external stimuli and to the plant's tissue-specific and developmental program. We have previously demonstrated the essential role of a cooperative regulatory element (CAR), containing a G-box and H-box, in tissue-specific expression. In this paper, we focus on unde rstanding the requirement for cis-elements in the response of the CHS1 5 promoter to the abiotic elicitor HgCl2, mechanical wounding and infe ction with tobacco mosaic virus (TMV). Leaves of tobacco plants transf ormed with a chimeric CHS15 promoter-beta glucuronidase gene construct carrying a mutation at the G-box did not exhibit impaired promoter re sponse to wounding, but did show a 19% reduction in the response to Hg Cl2 and TMV. A mutation at the H-box within CAR resulted in a 30% incr ease in promoter response to wounding and reductions of 36 and 54% in the response to HgCl2 and TMV, respectively. These results suggest dif ferential utilization of regulatory cis-elements for stress-induced an d tissue-specific expression of the bean CHS15 promoter. (C) 1997 Else vier Science Ireland Ltd.