Embryogenesis: A New Start in Life.

Laux, Thomas; Jürgens, Gerd

doi:10.1105/tpc.9.7.989

Cited by 178 publications

(106 citation statements)

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“…Plant embryogenesis involves a strict orchestration of cell division, elongation, and differentiation (Meinke 1995;Laux and Jürgens 1997). A current hypothesis is that the plant hormone auxin provides positional information interpreted by the developing embryo to direct which cells divide and which cells elongate to form this polarized structure (Vroemen et al 1999).…”

Section: Discussionmentioning

confidence: 99%

ABP1 is required for organized cell elongation and division in Arabidopsis embryogenesis

Chen

Ullah²,

Young³

et al. 2001

Genes Dev.

301

246

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To directly address the function of a putative auxin receptor designated ABP1, a reverse genetic approach was taken to identify and characterize ABP1 mutant alleles in Arabidopsis. A homozygous null mutation in ABP1 confers embryo lethality. Null mutant embryos develop normally until the early stages of the globular embryo but are unable to make the transition to a bilaterally symmetrical structure because cells fail to elongate. Cell division was also aberrant both in the suspensor and embryo proper. Antisense suppression of ABP1 in tobacco cells causes slow proliferation and eliminates auxin-induced cell elongation and reduces cell division. The complete lack of auxin-inducible elongation in individual cells confirms the results observed in embryos, indicates a cell autonomous function, and, taken together with biochemical evidence that ABP1 binds auxins, suggests that ABP1 mediates auxin-induced cell elongation and, directly or indirectly, cell division.

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Section: Discussionmentioning

confidence: 99%

ABP1 is required for organized cell elongation and division in Arabidopsis embryogenesis

Chen

Ullah²,

Young³

et al. 2001

Genes Dev.

301

246

View full text Add to dashboard Cite

show abstract

“…Two important morphological events occurring during the initial phases of embryogenesis in both angiosperms (see Laux and Jurgens, 1997) and gymnosperms (Yeung et al, 1998) are the formation of a SAM and a root apical meristem. Although some of the genetic processes controlling these events have been elucidated in flowering plants (Scheres et al, 1994;Fletcher and Meyerowitz, 2000), no information is currently available for conifers.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Polyethylene Glycol on Gene Expression of Developing White Spruce Somatic Embryos

et al. 2003

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Somatic embryogenic cultures of white spruce (Picea glauca) represent a valuable system to study molecular mechanisms regulating embryo development because many embryos of defined developmental stages can be generated. The inclusion of polyethylene glycol (PEG) in the maturation medium can improve the number and quality of embryos produced. To learn more about the mechanism of action of PEG, we analyzed transcript profiles of stage-specific embryos matured without (control) or with (PEG treated) PEG. RNA extracted from maturing spruce embryos was analyzed on DNA microarrays containing 2,178 cDNAs from loblolly pine (Pinus taeda). The efficiency of heterologous hybridization between spruce and pine species on microarrays has been documented previously (L. van Zyl, S. von Arnold, P. Bozhkov, Y. Chen, U. Egertsdotter, J. MacKay, R. Sederoff, J. Shen, L. Zelena, D. Clapham [2002] Comp Funct Genomics 3: 306-318). Several pine genes, including the apparent homologs to the Arabidopsis genes ZWILLE, FIDDLEHEAD, FUSCA, and SCARECROW, increased in expression after PEG treatments. These genes are known to be involved in the formation of the embryo body plan and in the control of the shoot and root apical meristems. The increased transcript levels of these genes in immature PEG-treated embryos suggest that PEG may improve the quality of spruce somatic embryos by promoting normal differentiation of the embryonic shoot and root. Changes in the transcript levels of many genes involved in sucrose catabolism and nitrogen assimilation and utilization were also observed between control and PEG-treated embryos.Embryogenesis is a critical stage of the plant life cycle because it establishes the basic body plan. Little is known about the molecular mechanisms that regulate the process (Harada, 1999). This paucity of information is partially because of the location of the embryos, which are embedded within the maternal tissue and are difficult to dissect. The generation of embryos in culture through somatic embryogenesis has become a model system for investigating factors that affect embryo growth. Somatic embryogenesis provides a large number of embryos at defined stages of development, and allows alterations of the embryonic environment through manipulations of the culture conditions. White spruce (Picea glauca) is an economically important species in North America, utilized for pulpwood and lumber production (Hosie, 1979). Regeneration of this species via somatic embryogenesis (Hakman and Fowke, 1987;Lu and Thorpe, 1987) has represented a means of propagation and a model system for conducting physiological and biochemical studies (for review, see Stasolla et al., 2002). Generation of white spruce somatic embryos is commonly achieved by transferring embryogenic tissue onto an abscisic acid (ABA)-containing maturation medium (Lu and Thorpe, 1987). Although such embryos may appear "morphologically" mature, they do not perform well during postembryonic growth without the imposition of a drying period. Improvement of embryo quality can ...

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“…What mechanisms are involved in pattern formation? Conceptually, when focusing on those patterning steps that involve asymmetric cell divisions, two mechanisms of pattern formation can be envisioned (Laux and Jürgens 1997). First, a cell with intrinsic polarity divides to generate two different daughter cells.…”

Section: Mechanisms Of Pattern Formationmentioning

confidence: 99%

“…The future apical -basal axis is already apparent before fertilization by the intrinsic polarity of the egg cell (Mansfield and Briarty 1991;Laux and Jürgens 1997). This cell has its nucleus and most of the cytoplasm at one side of the cell and a large vacuole at the opposite end.…”

mentioning

confidence: 99%