A METHOD FOR CONTROLLING AND DETERMINING PLANT ORGAN MORPHOGENESIS, A HOMEOTIC GENE, A PROMOTER ELEMENT THEREFOR, AND RELATED USES THEREOF

摘要

A method for controlling the morphogenesis of plant organs is disclosed which comprises causing the underexpression of a homeotic gene responsible for determining the identity of the plant organ in object. The method has particular application to flowers, where, by way of a first example herein, the flower petunia has been modified to present an additional whorl of petals derived from the modification of sepals. The additional whorl of petals may be formed by the conversion of sepals to petals, and/or by the stimulation of the growth of the existing petal structures to define inverted structures that appear to present a second whorl. The hometoic gene green petal in petunia has been cloned and characterized and is presented herein, both alone and in association with expression control sequences and in vectors for transgenic ectopic expression. In a second example, the same flower may be modified to present a whorl of petals having sepaloid characteristics along at least a portion thereof. The invention extends to a promoter construct derived from the CaMV 35S promoter and designated herein m35S. The promoter is particularly suited for the construction of homeotic transgenes in accordance wtih the present method. Petunia flowers having a whorl of modified petals prepared by the present method are likewise disclosed.