Nuclear replication activities during imbibition of abscisic acid- and gibberellin-deficient tomato (Lycopersicon esculentum Mill.) seeds

Liu, Yongqing; Bergervoet, J.H.W.; Vos, C. H. Ric De; Hilhorst, Henk W. M.; Kraak, H.L.; Karssen, C.M.; Bino, R.J.

doi:10.1007/bf00197537

Cited by 46 publications

(41 citation statements)

References 27 publications

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“…As was previously observed (Bino et al, 1992(Bino et al, , 1993Liu et al, 1994Liu et al, , 1997de Castro et al, 1995de Castro et al, , 1998, the levels of 4C DNA and ␤-tubulin were low in embryos of dry control tomato seeds. In the dry state most metabolic activities in the seed are suppressed (Roberts and Ellis, 1989), which may contribute to the arrest of the cell cycle in the G 1 phase.…”

Section: Dna Synthesis and Appearance Of Microtubule Arrays Is Correlsupporting

confidence: 84%

Cell Division and Subsequent Radicle Protrusion in Tomato Seeds Are Inhibited by Osmotic Stress But DNA Synthesis and Formation of Microtubular Cytoskeleton Are Not

Castro

Lammeren

Groot³

et al. 2000

Plant Physiology

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131

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We studied cell cycle events in embryos of tomato (Lycopersicon esculentum Mill. cv Moneymaker) seeds during imbibition in water and during osmoconditioning ("priming") using both quantitative and cytological analysis of DNA synthesis and ␤-tubulin accumulation. Most embryonic nuclei of dry, untreated control seeds were arrested in the G 1 phase of the cell cycle. This indicated the absence of DNA synthesis (the S-phase), as confirmed by the absence of bromodeoxyuridine incorporation. In addition, ␤-tubulin was not detected on western blots and microtubules were not present. During imbibition in water, DNA synthesis was activated in the radicle tip and then spread toward the cotyledons, resulting in an increase in the number of nuclei in G 2 . Concomitantly, ␤-tubulin accumulated and was assembled into microtubular cytoskeleton networks. Both of these cell cycle events preceded cell expansion and division and subsequent growth of the radicle through the seed coat. The activation of DNA synthesis and the formation of microtubular cytoskeleton networks were also observed throughout the embryo when seeds were osmoconditioned. However, this preactivation of the cell cycle appeared to become arrested in the G 2 phase since no mitosis was observed. The pre-activation of cell cycle events in osmoconditioned seeds appeared to be correlated with enhanced germination performance during re-imbibition in water.

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Section: Dna Synthesis and Appearance Of Microtubule Arrays Is Correlsupporting

confidence: 84%

Cell Division and Subsequent Radicle Protrusion in Tomato Seeds Are Inhibited by Osmotic Stress But DNA Synthesis and Formation of Microtubular Cytoskeleton Are Not

Castro

Lammeren

Groot³

et al. 2000

Plant Physiology

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131

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“…A Role for Progression through S Phase in ABA-mediated Activation-The dramatic increase in seed ABA content during the maturation phase has been proposed to play a role in cell cycle arrest at the G 1 /S phase transition (44). ABA has been reported to counter the effect of cytokinins in the shoot meristem by inactivating replication origins, leading to a reduction in DNA synthesis (45).…”

Section: Pvalf-and Aba-mediated Activation Of the Phas Promotermentioning

confidence: 99%

S Phase Progression Is Required for Transcriptional Activation of the β-Phaseolin Promoter

Chandrasekharan

Li²,

Bishop

et al. 2003

Journal of Biological Chemistry

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Elucidating the mechanisms by which the transcription machinery accesses promoters in their chromatin environment is a fundamental aspect of understanding gene regulation. The phas promoter is normally constrained by a rotationally and translationally positioned nucleosome over its TATA region except during embryogenesis when it is potentiated by the presence of Phaseolus vulgaris ABI3-like factor (PvALF), a plantspecific transcription factor, and activated by an abscisic acid (

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“…6 and 8) and the influence that relatively few seeds with exceptional activity can have in pooled samples. In addition, because of low ABA content during development, sit" seeds are prone to vivipary and exhibit cell cycle activity and free space in the dry seed characteristic of seeds that have progressed toward germination prior to dehydration (Argerich and Bradford, 1989;Groot and Karssen, 1992;Liu et al, 1993Liu et al, ,1994Hilhorst and Downie, 1996). Thus, they are in some respects similar to osmotically treated (primed) seeds that also exhibit high mannanase activity ( Fig.…”

Section: T5 Seeds Cerminating At Reduced +mentioning

confidence: 99%

Endo-β-Mannanase Activity from Individual Tomato Endosperm Caps and Radicle Tips in Relation to Germination Rates

Still

Bradford

1997

Plant Physiology

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~ ~ ~~Endo-P-mannanase is hypothesized to be a rate-limiting enzyme in endosperm weakening, which is a prerequisite for radicle emergente from tomato (Lycopersicon esculentum Mill.) seeds. Using a sensitive, single-seed assay, we have measured mannanase activity diffusing from excised tomato endosperm caps following treatments that alter the rate or percentage of radicle emergence. Most striking was the 100-to more than 10,000-fold range of mannanase activity detected among individual seeds of highly inbred tomato lines, which would not be detected in pooled samples. In some cases a threshold-type relationship between mannanase activity and radicle emergence was observed. However, when radicle emergence was delayed or prevented by osmoticum or abscisic acid, the initial increase in mannanase activity was unaffected or even enhanced. Partially dormant seed lots displayed a bimodal distribution of activity, with low activity apparently associated with dormant seeds in the population. Gibberellin-and abscisic acid-deficient mutant seeds exhibited a wide range of mannanase activity, consistent with their variation in hormonal sensitivity. Although the presence of mannanase activity in the endosperm cap is consistently associated with radicle emergence, it is not the sole or limiting factor under all conditions.Even though tomato (Lycopersicon esculentum Mill.) is self-pollinating and cultivars are highly homozygous genetically, germination behavior varies considerably among individual seeds. We have developed a population-based hydrotime model that accurately describes germination time courses in response to environmental and hormonal factors (Bradford, 1990(Bradford, , 1995(Bradford, , 1996 Bradford, 1990, 1994; Bradford, 1992, 1993). This model is based on the assumption that individual seeds vary in their sensitivity to these factors and particularly in the sensitivity of radicle emergence to +. If the +, , is higher (more positive) than the actual seed +, radicle emergence will not occur. The lower (more negative) the & for radicle emergente relative to the ambient +, the more rapid germination will be. The distribution of Ic., values within the seed population therefore determines both the rate and final percentage of germination. Environmental and hormonal fac- (Ni and Bradford, 1993;Dutta and Bradford, 1994;Bradford, 1995Bradford, , 1996.The population-based hydrotime model can quantify and describe seed germination patterns, but it does not identify the physiological or biochemical basis of +, , .

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Nuclear replication activities during imbibition of abscisic acid- and gibberellin-deficient tomato (Lycopersicon esculentum Mill.) seeds

Cited by 46 publications

References 27 publications

Cell Division and Subsequent Radicle Protrusion in Tomato Seeds Are Inhibited by Osmotic Stress But DNA Synthesis and Formation of Microtubular Cytoskeleton Are Not

Cell Division and Subsequent Radicle Protrusion in Tomato Seeds Are Inhibited by Osmotic Stress But DNA Synthesis and Formation of Microtubular Cytoskeleton Are Not

S Phase Progression Is Required for Transcriptional Activation of the β-Phaseolin Promoter

Endo-β-Mannanase Activity from Individual Tomato Endosperm Caps and Radicle Tips in Relation to Germination Rates

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