Novel phenotypes and developmental arrest in early embryo specific mutants of maize

Heckel, Thierry; Werner, Karine; Sheridan, William F.; Dumas, Christian; Rogowsky, Peter

doi:10.1007/s004250050647

Cited by 30 publications

(25 citation statements)

References 39 publications

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“…Third, unlike in Arabidopsis where the primordia for the shoot and root are set apart early in embryogenesis, in maize the primordia for both the shoot and root appear to arise from the anterior side of the embryo that would give rise to the prospective SAM and RAM. Finally, in maize, dormancy occurs later during embryogenesis, leading to the formation of 5-6 leaf primordia in the embryo in contrast to Arabidopsis where there are no leaf primordia and the embryo is much less mature (Sheridan, 1995;Heckel et al, 1999). Without tissue-specific markers, it is difficult to compare fates of groups of cells in these two embryos.…”

Section: Zmscr Expression During Embryogenesismentioning

confidence: 93%

“…The process of pattern formation during plant embryogenesis has been extensively studied resulting in a definition of the spatial relationships among the different parts of the embryo (Ju¨rgens, 1995;Heckel et al, 1999). However, comparative studies of patterning processes during embryogenesis between Arabidopsis and maize are problematic for several reasons.…”

Section: Zmscr Expression During Embryogenesismentioning

confidence: 99%

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Conservation and Diversification of SCARECROW in Maize

et al. 2005

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The SCARECROW (SCR) gene in Arabidopsis is required for asymmetric cell divisions responsible for ground tissue formation in the root and shoot. Previously, we reported that Zea mays SCARECROW (ZmSCR) is the likely maize ortholog of SCR. Here we describe conserved and divergent aspects of ZmSCR. Its ability to complement the Arabidopsis scr mutant phenotype suggests conservation of function, yet its expression pattern during embryogenesis and in the shoot system indicates divergence. ZmSCR expression was detected early during embryogenesis and localized to the endodermal lineage in the root, showing a gradual regionalization of expression. Expression of ZmSCR appeared to be analogous to that of SCR during leaf formation. However, its absence from the maize shoot meristem and its early expression pattern during embryogenesis suggest a diversification of ZmSCR in the patterning processes in maize. To further investigate the evolutionary relationship of SCR and ZmSCR, we performed a phylogenetic analysis using Arabidopsis, rice and maize SCARECROW-LIKE genes (SCLs). We found SCL23 to be the most closely related to SCR in both eudicots and monocots, suggesting that a gene duplication resulting in SCR and SCL23 predates the divergence of dicots and monocots.

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Section: Zmscr Expression During Embryogenesismentioning

confidence: 93%

Section: Zmscr Expression During Embryogenesismentioning

confidence: 99%

Conservation and Diversification of SCARECROW in Maize

et al. 2005

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“…Further studies are needed to confirm whether or not these cells represent ESR precursor cells. The observation that the endosperm of embryoless mutant grains forms a normal-sized embryo cavity suggests that the endosperm has an intrinsic program for the formation of the ESR domain (Heckel et al, 1999).…”

Section: The Embryo-surrounding Regionmentioning

confidence: 99%

Nuclear Endosperm Development in Cereals and Arabidopsis thaliana

Olsen

2004

THE PLANT CELL ONLINE

413

379

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“…The early events in embryogenesis are, however, the most critical for plant body pattern formation, because it is during this process that the protodermal cell layer, primary apical meristems and the embryo polarity axis are set o. In embryo-speci®c mutants of angiosperms, deviations from the normal plan during early embryogenesis lead either to immediate developmental arrest or to progressive accumulation of errors in morphogenesis and generation of aberrant phenotypes (Dunn et al, 1997;Hamann et al, 1999;Heckel et al, 1999;Scanlon et al, 1997).…”

Section: Introductionmentioning

confidence: 97%

A key developmental switch during Norway spruce somatic embryogenesis is induced by withdrawal of growth regulators and is associated with cell death and extracellular acidification

Bozhkov

Filonova

Arnold

2002

Biotech & Bioengineering

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The biotechnology of somatic embryogenesis holds considerable promise for clonal propagation and breeding programs in forestry. To efficiently regulate the whole process of plant regeneration through somatic embryogenesis, it is of outmost importance to understand early developmental events when somatic embryos are just formed. In Norway spruce, somatic embryos transdifferentiate from proembryogenic masses (PEMs). This work describes the developmental dynamics (frequency distribution of PEMs and early somatic embryos) of the whole embryogenic suspension culture growing in the presence and absence of plant growth regulators (PGRs), auxin and cytokinin. The experiments have shown that PEM-to-somatic embryo transition is a key developmental switch that determines the yield and quality of mature somatic embryos and ultimately plant production. This switch was induced by the withdrawal of PGRs in cell suspension leading to a rapid accumulation of early somatic embryos (to a maximum of 75% of the entire population of suspension culture) and concomitant degradation of PEMs. The latter was evident from increased level of cell death measured through spectrophotometric Evans blue staining assay. Proembryogenic mass-to-embryo transition and concomitant activation of cell death were mediated by strong extracellular acidification. Therefore, buffering PGR-free culture medium at high (pH 5.8) or low (pH 4.5) levels of pH inhibited both PEM-to-embryo transition and cell death. The yield of mature somatic embryos on abscisic acid (ABA)-containing medium was increased up to 10-fold if the suspension culture had been pretreated for 1 to 9 days in unbuffered PGR-free medium. In this case a large proportion (75%) of the total number of mature embryos was formed within a short, 5-week, contact with ABA. The latter is practically important because prolonged contact with ABA suppresses the growth of somatic embryo plants. Based on these results, an improved method for regulating somatic embryogenesis was set up and tested for nine genotypes of Norway spruce. Over 800 plants regenerated from all tested genotypes demonstrated a good performance in the greenhouse and they were transferred to the field.

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Novel phenotypes and developmental arrest in early embryo specific mutants of maize

Cited by 30 publications

References 39 publications

Conservation and Diversification of SCARECROW in Maize

Conservation and Diversification of SCARECROW in Maize

Nuclear Endosperm Development in Cereals and Arabidopsis thaliana

A key developmental switch during Norway spruce somatic embryogenesis is induced by withdrawal of growth regulators and is associated with cell death and extracellular acidification

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