EBE, an AP2/ERF Transcription Factor Highly Expressed in Proliferating Cells, Affects Shoot Architecture in Arabidopsis.

MEHRNIA M; BALAZADEH S; ZANOR MI; MUELLER-ROEBER B

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Lugar: Rockville; Año: 2013 vol. 162 p. 842 - 857

0032-0889

A systematic screen for transcription factors controlling vegetative development in Arabidopsis thaliana identified ERF BUD ENHANCER (EBE; At5g61890) as a new regulator of axillary bud outgrowth and shoot branching. EBE is a member of the AP2/ERF family of transcription factors. EBE is strongly expressed in proliferating cells and is rapidly and transiently upregulated in axillary meristems upon main stem decapitation. Overexpression of EBE in transgenic plants triggers axillary bud formation and outgrowth, whereas its repression inhibits bud growth. Global transcriptome analysis of estradiol-inducible EBE over-expression lines revealed 48 EBE early-responsive genes of which 14 were up- and 34 were down-regulated. EBE activates several genes involved in cell cycle regulation and dormancy breaking including D-type cyclin CYCD3;3, transcription regulator DPa and BRCA1-associated RING domain 1 BARD1. Among the downregulated genes were DORMANCY ASSOCIATED PROTEIN1 (AtDRM1), its paralog AtARP4, MEDIATOR OF ABA-REGULATED DORMANCY1 (MARD1) and ZINC FINGER HOMEODOMAIN 5 (ZHD5). Bud-outgrowth regulatory cis-elements (SRE and Up1) were over-represented in the promoters of these genes relative to background. We suggest that EBE possibly exerts its main role through stimulation of dedifferentiation and cell proliferation.