Role of Aquaporins During Elongation Growth of Castor Bean Seedlings

Weig, Alfons; Eisenbarth, Daniel A.

doi:10.1007/978-1-4615-1203-5_48

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…High expression levels of particular PIP and TIP aquaporins have been associated with: (i) high cell expansion rates Kaldenhoff et al 1995;Chaumont et al 1998;Weig & Eisenbarth 2000) (ii) cell differentiation (Kaldenhoff et al 1995); (iii) cells that exhibit large changes in volume, e.g. guard cells and pulvinar motor cells (Kaldenhoff et al 1995;Sarda et al 1997;Fleuratlessard et al 1997) (iv) high rates of water flow through cells (Barrieu, Chaumont & Chrispeels 1998;Kirch et al 2000;Otto & Kaldenhoff 2000;Frangne et al 2001) (v) the formation of a large central vacuole .…”

Section: Patterns Of Mip Locationmentioning

confidence: 99%

Plant aquaporins: multifunctional water and solute channels with expanding roles

Tyerman¹,

Niemietz²,

Bramley³

2002

Plant Cell & Environment

561

360

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There is strong evidence that aquaporins are central components in plant water relations. Plant species possess more aquaporin genes than species from other kingdoms. According to sequence similarities, four major groups have been identified, which can be further divided into subgroups that may correspond to localization and transport selectivity. They may be involved in compatible solute distribution, gas-transfer (CO 2 , NH 3 ) as well as in micronutrient uptake (boric acid). Recent advances in determining the structure of some aquaporins gives further details on the mechanism of selectivity. Gating behaviour of aquaporins is poorly understood but evidence is mounting that phosphorylation, pH, pCa and osmotic gradients can affect water channel activity. Aquaporins are enriched in zones of fast cell division and expansion, or in areas where water flow or solute flux density would be expected to be high. This includes biotrophic interfaces between plants and parasites, between plants and symbiotic bacteria or fungi, and between germinating pollen and stigma. On a cellular level aquaporin clusters have been identified in some membranes. There is also a possibility that aquaporins in the endoplasmic reticulum may function in symplasmic transport if water can flow from cell to cell via the desmotubules in plasmodesmata. Functional characterization of aquaporins in the native membrane has raised doubt about the conclusiveness of expression patterns alone and need to be conducted in parallel. The challenge will be to elucidate gating on a molecular level and cellular level and to tie those findings into plant water relations on a macroscopic scale where various flow pathways need to be considered.

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Section: Patterns Of Mip Locationmentioning

confidence: 99%

Plant aquaporins: multifunctional water and solute channels with expanding roles

Tyerman¹,

Niemietz²,

Bramley³

2002

Plant Cell & Environment

561

360

View full text Add to dashboard Cite

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“…1 C) is accompanied by disappearance of the activity of a cell wall-bound invertase (Balane, 1997), indicating that sucrose is not hydrolysed but directly taken up into parenchyma cells. Second, the RcSCR1 mRNA amount is transiently increased in the elongation zone of dark-grown seedlings (Weig and Eisenbarth, 2000). Because companion cells do not possess RcSCR1 under these conditions, and idioblasts obviously reduce the RcSCR1 density, we have to assume that the increases in sucrose carrier transcripts are used to synthesise RcSCR1 in other cells (most likely parenchyma cells of the cortex) to take up sucrose from the apoplast (see sucrose profile in Fig.…”

Section: Discussionmentioning

confidence: 99%

Sucrose Carrier RcSCR1 is Involved in Sucrose Retrieval, but not in Sucrose Unloading in Growing Hypocotyls of Ricinus communis L.

Eisenbarth

Weig

2005

Plant Biology

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The transport of assimilates from source to sink tissues is mediated by the phloem. Along the vascular system the phloem changes its physiological function from loading phloem to transport and unloading phloem. Sucrose carrier proteins have been identified in the transport phloem, but it is unclear whether the physiological role of these transporters is phloem unloading of sucrose or retrieval of apoplasmic sucrose back into the sieve element/companion cell complex. Here, we describe the dynamic expression of the Ricinus communis sucrose carrier RcSCR1 in the hypocotyl at different sink strengths. Our results indicate that phloem unloading in castor bean is not catalysed by the phloem loader RcSCR1. However, this sucrose carrier represents the molecular basis of the sucrose retrieval mechanism along the transport phloem, which is dynamically adjusted to the sink strength. As a consequence, we assume that other release carrier(s) exist in sink tissues, such as the hypocotyl, in R. communis.

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“…Cells expand through increased water uptake and aquaporins, which act as channels facilitating rapid water transport, are up‐regulated in regions of cellular elongation (Ludevid et al ., 1992; Schünmann & Ougham, 1996; Smart et al ., 1998; Weig & Eisenbarth, 2000). A suspensor‐specific aquaporin gene, PtNIP1;1 (NIP, nodulin‐like intrinsic protein), has been characterized in loblolly pine.…”

Section: Embryogenesis and Seed Developmentmentioning

confidence: 99%

The cellular and molecular biology of conifer embryogenesis

2007

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511 Review SummaryGymnosperms and angiosperms are thought to have evolved from a common ancestor c . 300 million yr ago. The manner in which gymnosperms and angiosperms form seeds has diverged and, although broad similarities are evident, the anatomy and cell and molecular biology of embryogenesis in gymnosperms, such as the coniferous trees pine, spruce and fir, differ significantly from those in the most widely studied model angiosperm Arabidopsis thaliana . Molecular analysis of signaling pathways and processes such as programmed cell death and embryo maturation indicates that many developmental pathways are conserved between angiosperms and gymnosperms. Recent genomics research reveals that almost 30% of mRNAs found in developing pine embryos are absent from other conifer expressed sequence tag (EST) collections. These data show that the conifer embryo differs markedly from other gymnosperm tissues studied to date in terms of the range of genes transcribed. Approximately 72% of conifer embryo-expressed genes are found in the Arabidopsis proteome and conifer embryos contain mRNAs of very similar sequence to key genes that regulate seed development in Arabidopsis. However, 1388 loblolly pine ( Pinus taeda ) embryo ESTs (11.4% of the collection) are novel and, to date, have been found in no other plant. The data imply that, in gymnosperm embryogenesis, differences in structure and development are achieved by subtle molecular interactions, control of spatial and temporal gene expression and the regulating agency of a few unique proteins.New Phytologist (2007) 176 : 511-536

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Role of Aquaporins During Elongation Growth of Castor Bean Seedlings

Cited by 4 publications

References 10 publications

Plant aquaporins: multifunctional water and solute channels with expanding roles

Plant aquaporins: multifunctional water and solute channels with expanding roles

Sucrose Carrier RcSCR1 is Involved in Sucrose Retrieval, but not in Sucrose Unloading in Growing Hypocotyls of Ricinus communis L.

The cellular and molecular biology of conifer embryogenesis

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