Non-inductive conditions expose the cryptic bract of flower phytomeres in Arabidopsis thaliana.
The aerial plant architecture is built by phytomeres which are metameric units, each composed of a stem segment (internode) and a leaf with axillary meristem (node). In Arabidopsis thaliana, fully developed flower phytomeres lack the leaf even if they temporarily exhibit a cryptic bract (CB) during early development. Recently, we demonstrated that the CB becomes more prominent under non-inductive short-day conditions. However, a full outgrowth as cauline leaf is prevented by Polycomb-group (Pc-G) proteins which silence the MADS gene FLOWERING LOCUS C (FLC) encoding a repressor of FLOWERING LOCUS T (FT). Also the loss of SHORT VEGETATIVE PHASE (SVP) supresses ectopic leaves at the base of Pc-G deficient pedicels. Here we present new expression data of flowering genes LEAFY (LFY) and TWIN SISTER OF FT (TSF) and the re-analysis of morphological changes in Pc-G deficient plants suggesting that the specifications of CB and floral meristem (FM) are separated in time.
a Institute of Genetics ; Heinrich-Heine-University ; Düsseldorf , Germany.
Ralf
R
Müller-Xing
Daniel
D
Schubert
Justin
J
Goodrich
D017360:Arabidopsis / Q000033:anatomy & histology* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000378:metabolism; D035264:Flowers / Q000033:anatomy & histology* / Q000648:ultrastructure; D008954:Models, Biological; D017440:Photoperiod; D018520:Plant Shoots / Q000033:anatomy & histology
D029681:Arabidopsis Proteins
Arabidopsis; CB, cryptic bract; FLC, FLOWERING LOCUS C; FM, floral meristem; FT, FLOWERING LOCUS T; IM, inflorescence meristem; LFY, LEAFY; P0, P1, etc., numbering of floral primordia; Pc-G, Polycomb-group; RB, rudimentary bract; SAM, shoot apical meristem; STM, SHOOT MERISTEMLESS; SVP, SHORT VEGETATIVE PHASE; St1, floral stage 1 etc; Ste2, early floral stage 2; Stl2, late floral stage 2; TSF, TWIN SISTER OF FT.; cell specification; ev, emf2-10 vrn2-1; floral primordia; floral reversion; iCLF, clf-28 swn-7 CLF-GR; plant morphology; rIM, reverted inflorescence meristem