Inventors:
Elaine M. Tobin - Los Angeles CA
Shoji Sugano - Los Angeles CA
Assignee:
Regents of the University of California - Oakland CA
International Classification:
A01H 500
US Classification:
800298, 435419, 536 236, 800278, 800290, 800295
Abstract:
A gene designated CKB3 whose product interacts specifically with CCA1 has been identified through use of the yeast two-hybrid system. CKB3 is a structural and functional homologue of the regulatory () subunit of protein kinase CK2 in Arabidopsis. Recombinant CK2 can phosphorylate CCA1 in vitro. Furthermore, Arabidopsis plant extracts contain a CK2-like activity that affects the formation of a DNA-protein complex containing CCA1. Recombinant plants that overexpress CKB3 have been constructed. Overexpression of CKB3 results in increased CK2 activity and resulted in shorter periods of rhythmic expression of CCA1 and LHY, as well as of four other circadian clock-controlled genes. This resulted a significant shortening of time to flowering under short-day conditions. This change in flowering time was not accompanied by significant phenotypic changes in morphology. Alteration of CK2 activity, particularly through the overexpression of the CKB represents a new and effective way of modulating flowering time in plants.