SQUAMOSA-PROMOTER BINDING PROTEIN 1 initiates flowering in Antirrhinum majus through the activation of meristem identity genes
Article first published online: 26 FEB 2010
© 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd
The Plant Journal
Volume 62, Issue 4, pages 704–712, May 2010
How to Cite
Preston, J. C. and Hileman, L. C. (2010), SQUAMOSA-PROMOTER BINDING PROTEIN 1 initiates flowering in Antirrhinum majus through the activation of meristem identity genes. The Plant Journal, 62: 704–712. doi: 10.1111/j.1365-313X.2010.04184.x
- Issue published online: 11 MAY 2010
- Article first published online: 26 FEB 2010
- Received 11 January 2010; revised 8 February 2010; accepted 11 February 2010; published online 25 March 2010.
- Antirrhinum majus;
- flowering time;
- floral meristem identity genes;
- SQUAMOSA-PROMOTER BINDING PROTEIN;
- virus-induced gene silencing
The degree to which developmental genetic pathways are conserved across distantly related organisms is a major question in biology. In Arabidopsis thaliana (L.) Heynh., inflorescence development is initiated in response to a combination of external and internal floral inductive signals that are perceived across the whole plant, but are integrated within the shoot apical meristem. Recently, it was demonstrated that SQUAMOSA-PROMOTER BINDING PROTEIN (SBP)-box proteins regulate A. thaliana flowering time by mediating signals from the autonomous and photoperiod pathways, and by directly activating key genes involved in inflorescence and floral meristem identity, including FRUITFULL (FUL), APETALA1 (AP1) and LEAFY (LFY). In the distantly related core eudicot species Antirrhinum majus L., paralogous SBP-box proteins SBP1 and SBP2 have likewise been implicated in regulating the AP1 ortholog SQUAMOSA (SQUA). To test the hypothesis that SBP-box genes are also involved in the floral induction of A. majus, we used a reverse genetic approach to silence SBP1. SBP1-silenced lines are late to nonflowering, and show reduced apical dominance. Furthermore, expression and sequence analyses suggest that the SBP1-mediated transition to flowering occurs through the positive regulation of FUL/LFY homologs. Together, these data outline the utility of virus-induced gene silencing in A. majus, and provide new insight into the conservation of flowering time genetic pathways across core eudicots.