WOX2 and STIMPY-LIKE/WOX8 promote cotyledon boundary formation in Arabidopsis

Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
The Plant Journal (Impact Factor: 5.97). 07/2012; 72(4). DOI: 10.1111/j.1365-313X.2012.05113.x
Source: PubMed

ABSTRACT One of the key events in dicot plant embryogenesis is the emergence of the two cotyledon primordia, which marks the transition from radial symmetry to bilateral symmetry. In Arabidopsis thaliana, the three CUP-SHAPED COTYLEDON (CUC) genes are responsible for determining the boundary region between the cotyledons. However, the mechanisms controlling their transcription activation are not well understood. Previous studies found that several WOX family homeobox transcription factors are involved in embryo apical patterning and cotyledon development. Here we show that WOX2 and STIMPY-LIKE (STPL/WOX8) act redundantly to differentially regulate the expression of the CUC genes in promoting the establishment of the cotyledon boundary, without affecting the primary shoot meristem. Loss of both WOX2 and STPL results in reduced CUC2 and CUC3 expression in one side of the embryo, but an expansion of the CUC1 domain. Furthermore, we found that STPL is expressed in the embryo proper, and its activation is enhanced by the removal of WOX2, providing an explanation for the functional redundancy between WOX2 and STPL. Additional evidence also showed that WOX2 and STPL function independently in regulating different aspects of local auxin gradient formation during early embryogenesis.

Download full-text


Available from: Xuelin wu, Oct 13, 2014
44 Reads
    • "Genes involved in organ boundary establishment and marginal growth are not mutually exclusive, but somewhat overlap in determining lateral organ growth (Fig. 2; e.g. Xu et al., 2008; Takeda et al., 2011; Lie et al., 2012; Huang et al., 2012; Rubio- Somoza et al., 2014). Likewise, phytohormones may work in a combinatorial manner, probably through their interactions with transcription factors, to initiate axillary organ development (Fig. 2; Furutani et al., 2004; Koyama et al., 2007; Bell et al., 2012; Gendron et al., 2012; Lampugnani et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: I. II. III. IV. References SUMMARY: One of the most striking innovations in flower development is the congenital or postgenital union of petals (sympetaly) which has enabled dramatic specialization in flower structure and possibly accelerated speciation rates. Sympetalous flowers exhibit extraordinary variation in development, including the degree and timing of fusion, and fusion with other floral organs. Different axes of corolla tube complexity can be disentangled at the developmental level, with most variation being explained by differences in coordinated growth between interconnected and lobed regions of neighboring petal primordia, and between lower and upper portions of the corolla tube, defined by the stamen insertion boundary. Genetically, inter- and intra-specific variation in the degree of petal fusion is controlled by various inputs from genes that affect organ boundary and lateral growth, signaling between different cell types, and production of the cuticle. It is thus hypothesized that the evolution and diversification of fused petals, at least within the megadiverse Asteridae clade of core eudicots, have occurred through the modification of a conserved genetic pathway previously involved in free petal development. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
    New Phytologist 06/2015; DOI:10.1111/nph.13517 · 7.67 Impact Factor
  • Source
    • ". Whole-mount in situ was performed as described (Friml et al., 2003) except that 10 mg/ml of proteinase K (Sigma-Aldrich #P2308) was used for digestion. In situ hybridization on tissue sections was performed as previously described (Lie et al., 2012). The Dig-labeled anti-sense probes for ELO3 and STM were generated by in vitro transcription using the respective full-length cDNA as the template. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A key feature of the development of a higher plant is the continuous formation of new organs from the meristems. Originally patterned during embryogenesis, the meristems must activate cell division de novo at the time of germination, in order to initiate post-embryonic development. In a mutagenesis screen aimed at finding new players in early seedling cell division control, we identified ELONGATA3 (ELO3) as a key regulator of meristem cell cycle activation in Arabidopsis. Our results show that plants carrying a hypomorphic allele of ELO3 fail to activate cell division in the meristems following germination, which leads to seedling growth arrest and lethality. Further analyses suggest that this is due to a failure in DNA replication, followed by cell cycle arrest, in the meristematic tissue. Interestingly, the meristem cell cycle arrest in elo3 mutants, but not the later leaf developmental defects that have been linked to the loss of ELO3 activities, can be relieved by the addition of metabolic sugars in the growth medium. This finding points to a new role by which carbohydrate availability promotes meristem growth. Furthermore, growth arrested elo3 mutants suffer a partial loss of shoot meristem identity, which provides further evidence that cell cycle activities can influence the control of tissue identity.
    Developmental Biology 08/2013; 382(2). DOI:10.1016/j.ydbio.2013.08.008 · 3.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: During embryogenesis, the basic body plan of an organism develops from a unicellular zygote. In most flowering plants, the polar zygote divides asymmetrically, making visible the apical-basal axis in the early embryo. The molecular mechanisms governing how the zygote polarizes and how this polarity is linked to embryo axis formation have been obscure, mainly owing to the difficulties to access the zygote that is deeply embedded in the maternal tissue. In this review, we summarize recent findings identifying key regulators in Arabidopsis and developing novel approaches in various plant species, which altogether set the stage for unraveling embryo axis formation.
    Current opinion in plant biology 08/2012; 15(6). DOI:10.1016/j.pbi.2012.08.001 · 7.85 Impact Factor
Show more

Similar Publications