Developing Seeds of Arabidopsis Store Different Minerals in Two Types of Vacuoles and in the Endoplasmic Reticulum

Otegui, Marisa S.; Capp, Roberta; Staehelin, L. Andrew

doi:10.1105/tpc.010486

Cited by 153 publications

(112 citation statements)

References 50 publications

(60 reference statements)

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…Furthermore, when this rapid freezing is followed by freeze substitution, all of the water is substituted by acetone at -80°C, which faithfully preserves the three-dimensional architecture of the membranes up to the resin infiltration and polymerization steps. An added bonus is the retention of ions and salts within the vacuoles (Otegui et al, 2002), which we have exploited both to determine the ionic composition of the globoids and of the surrounding PSV matrix (Fig. 2, E-G) and to produce the phytin-dependent black osmium stain of the PSVs in the developing root cells (Figs.…”

Section: Cryofixation and Freeze-substitution Methods Are Important Fmentioning

confidence: 99%

See 1 more Smart Citation

Protein Storage Vacuoles Are Transformed into Lytic Vacuoles in Root Meristematic Cells of Germinating Seedlings by Multiple, Cell Type-Specific Mechanisms

Zheng

Staehelin

2011

Plant Physiology

Self Cite

View full text Add to dashboard Cite

We have investigated the structural events associated with vacuole biogenesis in root tip cells of tobacco (Nicotiana tabacum) seedlings preserved by high-pressure freezing and freeze-substitution techniques. Our micrographs demonstrate that the lytic vacuoles (LVs) of root tip cells are derived from protein storage vacuoles (PSVs) by cell type-specific sets of transformation events. Analysis of the vacuole transformation pathways has been aided by the phytin-dependent black osmium staining of PSV luminal contents. In epidermal and outer cortex cells, the central LVs are formed by a process involving PSV fusion, storage protein degradation, and the gradual replacement of the PSV marker protein a-tonoplast intrinsic protein (TIP) with the LV marker protein g-TIP. In contrast, in the inner cortex and vascular cylinder cells, the transformation events are more complex. During mobilization of the stored molecules, the PSV membranes collapse osmotically upon themselves, thereby squeezing the vacuolar contents into the remaining bulging vacuolar regions. The collapsed PSV membranes then differentiate into two domains: (1) vacuole "reinflation" domains that produce pre-LVs, and (2) multilamellar autophagosomal domains that are later engulfed by the pre-LVs. The multilamellar autophagosomal domains appear to originate from concentric sheets of PSV membranes that create compartments within which the cytoplasm begins to break down. Engulfment of the multilamellar autophagic vacuoles by the pre-LVs gives rise to the mature LVs. During pre-LV formation, the PSV marker a-TIP disappears and is replaced by the LV marker g-TIP. These findings demonstrate that the central LVs of root cells arise from PSVs via cell type-specific transformation pathways.

show abstract

Section: Cryofixation and Freeze-substitution Methods Are Important Fmentioning

confidence: 99%

“…Sections 0.25 to 0.5 mm in thickness were cut with a dry glass knife to avoid washing out the soluble mineral deposits as described by Otegui et al (2002), mounted on copper grids, flattened onto the grid surface by a very brief exposure to moist air, and then coated with carbon. More than five root tips were used to obtain the EDXS data.…”

Section: Edxs Analysismentioning

confidence: 99%

Protein Storage Vacuoles Are Transformed into Lytic Vacuoles in Root Meristematic Cells of Germinating Seedlings by Multiple, Cell Type-Specific Mechanisms

Zheng

Staehelin

2011

Plant Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the size of the posterior zone of expression of KS117 was much reduced in the iku endosperm, in agreement with the reduced size of the iku cyst. The posterior endosperm is of potential importance for transfer of maternal nutrients to the seed (Schultz and Jensen, 1971;Otegui et al, 2002). To test whether the reduction of the cyst in iku seeds is responsible for the reduction of the size of the endosperm we combined iku mutation to mutants of the fis class that are characterized by over-proliferation of posterior structures ( Fig.…”

Section: Polarity Of Endosperm In Haiku Mutantsmentioning

confidence: 99%

Arabidopsis haiku Mutants Reveal New Controls of Seed Size by Endosperm

et al. 2003

View full text Add to dashboard Cite

In flowering plants, maternal seed integument encloses the embryo and the endosperm, which are both derived from double fertilization. Although the development of these three components must be coordinated, we have limited knowledge of mechanisms involved in such coordination. The endosperm may play a central role in these mechanisms as epigenetic modifications of endosperm development, via imbalance of dosage between maternal and paternal genomes, affecting both the embryo and the integument. To identify targets of such epigenetic controls, we designed a genetic screen in Arabidopsis for mutants that phenocopy the effects of dosage imbalance in the endosperm. The two mutants haiku 1 and haiku 2 produce seed of reduced size that resemble seed with maternal excess in the maternal/paternal dosage. Homozygous haiku seed develop into plants indistinguishable from wild type. Each mutation is sporophytic recessive, and double-mutant analysis suggests that both mutations affect the same genetic pathway. The endosperm of haiku mutants shows a premature arrest of increase in size that causes precocious cellularization of the syncytial endosperm. Reduction of seed size in haiku results from coordinated reduction of endosperm size, embryo proliferation, and cell elongation of the maternally derived integument. We present further evidence for a control of integument development mediated by endosperm-derived signals.In flowering plants, the two female gametes, the egg cell and the central cell, are fertilized by one of the two male gametes delivered by the pollen tube. The zygotic product of the fusion of one male gamete with the egg cell develops into the embryo of the daughter plant. The fertilized central cell develops as the endosperm that nurtures embryo development. In most species, endosperm development is initiated by a proliferative syncytial phase accompanied by cell growth that generates a large multinucleate cell (Olsen, 2001; Berger, 2003). This syncytium is partitioned into individual cells by a specific type of cytokinesis called cellularization. In cereal species, the cellular endosperm stores the reserves of the seed during a phase marked by endoreduplication. Although the endosperm does not store the reserves of the seed in Arabidopsis, it most probably controls the flux of nutrients delivered by the vascular tissue of the mother to the embryo and protects the embryo from physical and osmotic stresses.Because the embryo is surrounded by the endosperm, which, in turn, is enclosed within the ovule integument, these three structures must coordinate their development to produce a mature seed of the appropriate size. The endosperm plays a central role in the control of seed size as indicated by a series of experiments in Arabidopsis and maize (Zea mays), where the dosage balance between maternal and paternal genomes was perturbed (Lin, 1984;Kermicle and Allemand, 1990;Scott et al., 1998). In most flowering plants, the endosperm contains two maternal copies and one paternal copy of the genome (2m/1p). In Arabidop...

show abstract

“…Phytate (InsP6), which is primarily complexed with metal ions, is the principal storage form of phosphorus in seeds (Otegui et al, 2002) and pollen (Jackson and Linskens, 1982). The globoid in the protein storage vacuole of the Arabidopsis seed embryo is primarily composed of calcium/magnesium/potassium-phytate salts (phytin); thus, phytin breakdown in these cells releases phosphorus, calcium, magnesium, potassium, and carbon for embryo growth and division (Otegui et al, 2002). In pollen, small electron-dense globoids rich in calcium, magnesium, and phosphorus were only found within cytoplasmic vesicles of vegetative cells but not in germ cells (Butowt et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

Molecular and Biochemical Characterization of AtPAP15, a Purple Acid Phosphatase with Phytase Activity, in Arabidopsis

et al. 2009

View full text Add to dashboard Cite

Purple acid phosphatase (PAP) catalyzes the hydrolysis of phosphate monoesters and anhydrides to release phosphate within an acidic pH range. Among the 29 PAP-like proteins in Arabidopsis (Arabidopsis thaliana), AtPAP15 (At3g07130) displays a greater degree of amino acid identity with soybean (Glycine max; GmPHY) and tobacco (Nicotiana tabacum) PAP (NtPAP) with phytase activity than the other AtPAPs. In this study, transgenic Arabidopsis that expressed an AtPAP15 promoter:: b-glucuronidase (GUS) fusion protein showed that AtPAP15 expression was developmentally and temporally regulated, with strong GUS staining at the early stages of seedling growth and pollen germination. The expression was also organ/tissue specific, with strongest GUS staining in the vasculature, pollen grains, and roots. The recombinant AtPAP purified from transgenic tobacco exhibited broad substrate specificity with moderate phytase activity. AtPAP15 T-DNA insertion lines exhibited a lower phytase and phosphatase activity in seedling and germinating pollen and lower pollen germination rate compared with the wild type and their complementation lines. Therefore, AtPAP15 likely mobilizes phosphorus reserves in plants, particularly during seed and pollen germination. Since AtPAP15 is not expressed in the root hair or in the epidermal cells, it is unlikely to play any role in external phosphorus assimilation.

show abstract

Developing Seeds of Arabidopsis Store Different Minerals in Two Types of Vacuoles and in the Endoplasmic Reticulum

Cited by 153 publications

References 50 publications

Protein Storage Vacuoles Are Transformed into Lytic Vacuoles in Root Meristematic Cells of Germinating Seedlings by Multiple, Cell Type-Specific Mechanisms

Protein Storage Vacuoles Are Transformed into Lytic Vacuoles in Root Meristematic Cells of Germinating Seedlings by Multiple, Cell Type-Specific Mechanisms

Arabidopsis haiku Mutants Reveal New Controls of Seed Size by Endosperm

Molecular and Biochemical Characterization of AtPAP15, a Purple Acid Phosphatase with Phytase Activity, in Arabidopsis

Contact Info

Product

Resources

About