ARS | Publication request: Bearded-Ear Encodes a MADS-box Transcription Factor Critical for Maize Floral Development

Submitted to: The Plant Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 17, 2009
Publication Date: September 11, 2009
Repository URL: http://www.plantcell.org/cgi/reprint/21/9/2578?maxtoshow=&hits=10&RESULTFORMAT=&author1=Sarah+Hake&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT
Citation: Thompson, B.E., Bartling, L., Whipple, C., Hall, D.H., Sakai, H., Schmidt, R., Hake, S.C. 2009. Bearded-Ear Encodes a MADS-box Transcription Factor Critical for Maize Floral Development. The Plant Cell. 21:2578–2590.

Interpretive Summary: Although many genes that control floral development have been identified in Arabidopsis, relatively few are known in the grasses. In normal maize, each spikelet produces an upper and lower floral meristem, which initiate floral organs in a defined phyllotaxy before being consumed in the production of an ovule. bearded ear (bde) mutants affect floral development differently in the upper and lower meristem. The upper floral meristem initiates extra floral organs that have identity defects, while the lower floral meristem initiates additional floral meristems. We cloned BDE and show that it plays a important role in floral meristems and floral organs.

Technical Abstract: We cloned bde by positional cloning and found that it encodes zag3, a MADS-box transcription factor in the conserved AGL6 clade. Mutants in the maize homolog of AGAMOUS, zag1, have a subset of bde floral defects. bde; zag1 double mutants have a severe ear phenotype, not observed in either single mutant, in which floral meristems are converted to branch-like meristems, indicating bde and zag1 redundantly promote floral meristem identity. In addition, BDE and ZAG1 physically interact. We propose a model in which BDE functions in at least three distinct complexes to regulate floral development in the maize ear.