Received October 5, 2006
Accepted November 7, 2006
SVP-like MADS-box genes Inhibit Floral Meristem Identity in Barley
Ben Trevaskis , Million Tadege , Megan N. Hemming , W. James Peacock , Elizabeth S. Dennis *, and Candice Sheldon
Commonwealth Scientific and Industrial Research Organisation, Division of Plant Industry, GPO Box 1600, Canberra ACT 2601, Australia
Commonwealth Scientific and Industrial Research Organisation, Division of Plant Industry, GPO Box 1600, Canberra ACT 2601, Australia; Graingene, Canberra Avenue Executive Centre, 65 Canberra Avenue, Griffith ACT 2603, Australia; Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
* Corresponding author; email: liz.dennis{at}csiro.au.
Analysis of the functions of SVP-like MADS-box genes in barley indicated a role in determining meristem identity. Three SVP-like genes are expressed in vegetative tissues of barley; BM1, BM10 and HvVRT2. These genes are induced by cold, but are repressed during floral development. Ectopic expression of BM1 inhibited spike development and caused floral reversion in barley, with florets at the base of the spike replaced by tillers. Head emergence was delayed in plants that ectopically express BM1, primarily by delayed development after the floral transition, but expression levels of HvVRN1 were not affected. Ectopic expression of BM10 inhibited spike development and caused partial floral reversion, where florets at the base of the spike were replaced by inflorescence-like structures, but did not affect heading date. Floral reversion occurred more frequently when BM1 and BM10 ectopic expression lines were grown in short-day conditions. BM1 and BM10 also inhibited floral development and caused floral reversion when expressed in Arabidopsis. We conclude that SVP-like genes function to suppress floral meristem identity in winter cereals.
