Molecular and genetic interactions betweenSTYLOSAandGRAMINIFOLIAin the control ofAntirrhinumvegetative and reproductive development

Abstract

GRAMINIFOLIA (GRAM), is supported by enhanced phenotypic defects in sty gram double mutants, for instance in the control of phyllotaxis, floral homeotic functions and organ polarity. Accordingly, the STY and GRAM protein and mRNA expression patterns overlap in emerging lateral organ primordia. STY is expressed in all meristems and later becomes confined to the adaxial domain and (pro)-vascular tissue. This pattern is similar to genes that promote adaxial identity, and, indeed, STY expression follows, although does not control, adaxial fate. We discuss the complex roles of STY and GRAM proteins in reproductive and vegetative development, performed in part in physical association but also independently.

SEUSSandAINTEGUMENTAMediate Patterning and Ovule Initiation during Gynoecium Medial Domain Development

“…One molecular explanation for a differential requirement for SEU and LUG is that they may have multiple protein partners and may participate in a number of different complexes that are required for diverse developmental events. A family of SEUSS-LIKE (SLK) genes has been described in Arabidopsis (Franks et al, 2002), and Antirrhinum members of this family have been shown to physically interact with STYLOSA, the Antirrhinum LEU ortholog (Navarro et al, 2004). Thus, the SLK gene family may support SEU-independent activities of LUG in the seu mutant plants.…”

“…These phenotypes are not observed in the seu ant double mutants (data not shown), highlighting a degree of functional differentiation between SEU and YAB1/ FIL. Evidence that SEU and LUG may physically cooperate with YAB1/FIL comes from the analysis of orthologous genes in Antirrhinum majus (Navarro et al, 2004). STYLOSA (STY), the Antirrhinum ortholog of LUG, has been shown to interact physically with members of the Antirrhinum YABBY and SLK gene families suggesting that the orthologous Arabidopsis proteins (SEU, YAB1/FIL, CRC, and LUG) may be part of a multimeric complex important for the development of the medial domain of the gynoecium.…”

“…These three functions support medial domain development and ovule initiation in wild-type gynoecia. Additional members of the SLK (Franks et al, 2002;Navarro et al, 2004), AIL (Nole-Wilson et al, 2005), YABBY (Siegfried et al, 1999), and LUG/LEUNIG-HOMOLOGUE (Conner and Liu, 2000) gene families are likely to provide molecular redundancy by also participating in this multicomponent molecular complex. Mutant combinations that disrupt at least two of these protein subunits can result in a dramatic loss of the gynoecium medial domain (e.g.…”

LEUNIG_HOMOLOGandLEUNIGPerform Partially Redundant Functions during Arabidopsis Embryo and Floral Development

“…lug mutants showed defects in gynoecium development, female and male fertility, leaf and floral organ shape, and vasculature (Liu and Meyerowitz, 1995;Chen et al, 2000;Liu et al, 2000;Cnops et al, 2004;Franks et al, 2006). Antirrhinum mutants of STYLOSA, a LUG ortholog, not only showed abnormal flower development but also exhibited hypersensitivity toward auxin and polar auxin inhibitors (Navarro et al, 2004). A transcriptome study identified LUG-regulated genes in abiotic and biotic stress response, meristem function, and transport (Gonzalez et al, 2007).…”

A conserved microRNA module exerts homeotic control over Petunia hybrida and Antirrhinum majus floral organ identity

“…Several transcription factors participate in this control, which aims at transcriptional silencing of the so-called 'C genes' outside their genuine expression domain in the inner two whorls of the flower, where they govern reproductive organ (stamen and carpel) development 6,7 . The functions of orthologous repressor genes, constituting the A function of the floral ABCs 6 , are, in part, comparable between different species 8 , as are some of the cis-acting regulatory regions within the large second intron of their structurally and functionally related target C genes AGAMOUS (AG) in Arabidopsis thaliana 7 , pMADS3 in P. hybrida 9 and PLENA and FARINELLI (PLE and FAR) in A. majus 10 . There are also exceptions to these overall similarities among species.…”