Control of
            <i>Arabidopsis</i>
            meristem development by thioredoxin-dependent regulation of intercellular transport

Benitez‐Alfonso, Yoselin; Cilia, Michelle; Roman, Adrianna San; Thomas, Colwyn M.; Maule, Andy; Hearn, Stephen; Jackson, David

doi:10.1073/pnas.0808717106

Cited by 244 publications

(210 citation statements)

References 49 publications

(57 reference statements)

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“…Another mutant with reduced intercellular movement, GFP arrested trafficking 1 (gat1) contains 9% branched PD in the root apical meristem (26), similar to the 10% observed in WT embryos in the present study and in a previous intensive quantitative study of PD in immature WT tissues (15). However, 5% of gat1 PD were occluded, but none were occluded in dse1 embryos.…”

Section: Discussionsupporting

confidence: 87%

“…All five of these mutants produce severe phenotypes during embryo or seedling development; however, except GSL8 none encodes proteins that localize to PD. ISE1 encodes a mitochondrial DEAD-box RNA helicase (22), ISE2 encodes a chloroplast DEVH-type RNA helicase (23,30), GAT1 encodes a chloroplast thioredoxin (26), and DSE1 encodes a WDR protein that localizes to the nucleus and cytoplasm. Only, GSL8 encodes a putative glucan synthase, that may localize close to PD, as it is involved in callose deposition in cell walls at the cell plate (31).…”

Section: Discussionmentioning

confidence: 99%

“…Plastid homeostasis is very important to PD structure and function. GAT1 localizes to plastids (26), and ise1 and ise2 both dramatically affect the expression of more than 300 nuclear genes essential for chloroplast function (30). Finally, a mutant of corn, sucrose export defective 1, with decreased PD mediated transport from the phloem encodes a protein that localizes to chloroplasts (32).…”

Section: Discussionmentioning

confidence: 99%

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Plasmodesmata formation and cell-to-cell transport are reduced in decreased size exclusion limit 1 during embryogenesis in Arabidopsis

Cho

Burch‐Smith

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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In plants, plasmodesmata (PD) serve as channels for micromolecular and macromolecular cell-to-cell transport. Based on structure, PD in immature tissues are classified into two types, simple and branched (X-and Y-shaped) or twinned. The maximum size of molecules capable of PD transport defines PD aperture, known as the PD size exclusion limit. Here we report an Arabidopsis mutation, decreased size exclusion limit1 (dse1), that exhibits reduced cell-to-cell transport of the small (524 Da) fluorescent tracer 8-hydroxypyrene-1,3,6-trisulfonic acid at the midtorpedo stage of embryogenesis. Correspondingly, the fraction of X-and Y-shaped and twinned PD was reduced in dse1 embryos compared with WT embryos at this stage, suggesting that the frequency of PD is related to transport capability. dse1 is caused by a point mutation in At4g29860 (previously termed TANMEI) at the last donor splice site of its transcript, resulting in alternative splicing in both the first intron and the last intron. AtDSE1 is a conserved eukaryotic 386-aa WD-repeat protein critical for Arabidopsis morphogenesis and reproduction. Similar to its homologs in mouse, null mutants are embryo-lethal. The weak loss-of-function mutant dse1 exhibits pleiotropic phenotypes, including retarded vegetative growth, delayed flowering time, dysfunctional male and female organs, and delayed senescence. Finally, silencing of DSE1 in Nicotiana benthamiana leaves leads to reduced movement of GFP fused to tobacco mosaic virus movement protein. Thus, DSE1 is important for regulating PD transport between plant cells.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Plasmodesmata formation and cell-to-cell transport are reduced in decreased size exclusion limit 1 during embryogenesis in Arabidopsis

Cho

Burch‐Smith

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…SUC2 is specifically expressed in companion cells, and GFP fluorescence was observed in the phloem and within two cell layers surrounding the phloem in the mature region of roots ( Figure 6G) as previously reported (Stadler et al, 2005). Free GFP diffused through the symplast into the whole root meristem ( Figure 6H) (Stadler et al, 2005;Benitez-Alfonso et al, 2009). Compared with free GFP (27 kD), NaKR1-GFP (61 kD) was more restricted to the phloem in mature roots.…”

Section: Nakr1 Is Specifically Expressed In the Phloemsupporting

confidence: 83%

“…The mutant line 136:31 (Lahner et al, 2003) (Bonke et al, 2003) was obtained from Ykä Helariutta (University of Helsinki, Finland). The JYB1234 marker line was described previously (Benitez-Alfonso et al, 2009). These marker lines were crossed with nakr1-1 mutants, and the F2 progeny with short roots and containing these constructs (selected by the expression of GUS or GFP) were selected.…”

Section: Plant Materialsmentioning

confidence: 99%

Arabidopsis NPCC6/NaKR1 Is a Phloem Mobile Metal Binding Protein Necessary for Phloem Function and Root Meristem Maintenance

et al. 2010

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SODIUM POTASSIUM ROOT DEFECTIVE1 (NaKR1; previously called NPCC6) encodes a soluble metal binding protein that is specifically expressed in companion cells of the phloem. The nakr1-1 mutant phenotype includes high Na + , K + , Rb + , and starch accumulation in leaves, short roots, late flowering, and decreased long-distance transport of sucrose. Using traditional and DNA microarray-based deletion mapping, a 7-bp deletion was found in an exon of NaKR1 that introduced a premature stop codon. The mutant phenotypes were complemented by transformation with the native gene or NaKR1-GFP (green fluorescent protein) and NaKR1-b-glucuronidase fusions driven by the native promoter. NAKR1-GFP was mobile in the phloem; it moved from companion cells into sieve elements and into a previously undiscovered symplasmic domain in the root meristem. Grafting experiments revealed that the high Na + accumulation was due mainly to loss of NaKR1 function in the leaves. This supports a role for the phloem in recirculating Na + to the roots to limit Na + accumulation in leaves. The onset of root phenotypes coincided with NaKR1 expression after germination. The nakr1-1 short root phenotype was due primarily to a decreased cell division rate in the root meristem, indicating a role in root meristem maintenance for NaKR1 expression in the phloem.

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Plasmodesmata

Faulkner

Oparka

2016

Encyclopedia of Life Sciences

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Plasmodesmata are plasma membrane‐lined pores that span the adjoining walls of plant cells. They permit the intercellular passage of molecules and signals and play a central role in plant physiology and development. Evidence suggests that small molecules can pass from cell to cell by passive diffusion and that this is controlled by regulation of the pore itself. This contributes to processes such as the transport of sugars between cells and tissues. Many endogenous plant proteins and ribonucleic acid (RNA)‐based signals also utilise plasmodesmata for cell‐to‐cell and long‐distance movement. Recent data suggests that plasmodesmata are tightly controlled during development and in response to environmental changes. There is increasing evidence that this regulation is controlled by proteins that have specific plasmodesmata‐associated functions in stimulus perception and signalling. In addition, many viruses exploit plasmodesmata for cell‐to‐cell spread during infection and their encoded viral movement proteins manipulate the pores to facilitate this process. Key Concepts Plant cells are connected to each other by cytoplasmic bridges called plasmodesmata. The continuous interconnected cytoplasm in plants is referred to as the symplasm. A tube of endoplasmic reticulum passes through plasmodesmata and connects the endoplasmic reticulum of neighbouring cells, thus providing endomembrane continuity between cells. Primary plasmodesmata are formed at cytokinesis when strands of endoplasmic reticulum are trapped between fusing vesicles in the developing cell wall. Secondary plasmodesmata are formed across existing cell walls, including those at graft unions, and usually arise immediately adjacent to existing plasmodesmata. Molecules smaller than the size exclusion limit (SEL) of plasmodesmata are able to move freely through the cytoplasmic channel of plasmodesmata by simple diffusion. The SEL of plasmodesmata may increase or decrease to allow changes in plasmodesmatal conductance. This may occur under different conditions, for example, in response to intracellular factors such as cytoplasmic calcium levels or pathogen perception. Some endogenous proteins and some movement proteins encoded by plant viruses are able to increase the SEL of plasmodesmata to facilitate their own passage into neighbouring cells. This enables these proteins to function in cells in which they are not normally expressed. Groups of cells may be connected by plasmodesmata that share an SEL different to that of neighbouring cells. These regions of cells are called symplasmic domains. Some proteins and RNA molecules pass into the plant's translocation stream and move over long distances. These macromolecules traffic through the plasmodesmata that join sieve elements (SE) and companion cells within the phloem. These macromolecules may have a site of action distant to their site of expression and synthesis.

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Control of Arabidopsis meristem development by thioredoxin-dependent regulation of intercellular transport

Cited by 244 publications

References 49 publications

Plasmodesmata formation and cell-to-cell transport are reduced in decreased size exclusion limit 1 during embryogenesis in Arabidopsis

Plasmodesmata formation and cell-to-cell transport are reduced in decreased size exclusion limit 1 during embryogenesis in Arabidopsis

Arabidopsis NPCC6/NaKR1 Is a Phloem Mobile Metal Binding Protein Necessary for Phloem Function and Root Meristem Maintenance

Plasmodesmata

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