Last exit: senescence, abscission, and meristem arrest in Arabidopsis.

Bleecker, Anthony B.; Patterson, Sara E.

doi:10.1105/tpc.9.7.1169

Cited by 387 publications

(354 citation statements)

References 39 publications

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“…Senescing leaves are rich in sugars and other metabolites that are important for the plant to recover before the leaf eventually dies (33). AtPLT5 expression, visualized by GUS staining, was induced in cells surrounding the vascular tissue in the midvein in mature leaves.…”

Section: Discussionmentioning

confidence: 98%

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Analysis of Transport Activity of Arabidopsis Sugar Alcohol Permease Homolog AtPLT5

Reinders

Panshyshyn

Ward

2005

Journal of Biological Chemistry

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The transporters responsible for sugar uptake into non-photosynthetic sink tissues in plants, such as roots and flowers, have not been fully identified and analyzed. Plants encode around 100 putative sugar transporters within the major facilitator superfamily, yet only a few have been studied. Here we report the analysis of a sugar alcohol permease homolog (AtPLT5, At3g18830) from Arabidopsis. A wide range of sugars including hexoses, pentoses, tetroses, a sugar acid, and sugar alcohols but not disaccharides induced inward currents in oocytes expressing AtPLT5. AtPLT5 expression also resulted in 14 C-labeled substrate uptake in oocytes, indicating that AtPLT5 encodes an ion-coupled uptake transporter. K 0.5 values for glucose and sorbitol were highly dependent on external pH. Expression of AtPLT5 was found primarily in sink tissues: in the elongation zone of roots, in the inflorescence stem, and several floral structures, especially in the floral abscission zone. Expression was induced by mechanical wounding and insect feeding. Analysis of transport properties and expression in Arabidopsis indicate that AtPLT5 functions to transport a wide range of sugars into specific sink tissues in the plant.Most plant cells are connected by plasmodesmata, forming multicellular "symplasmic domains" (1) that allow exchange of small metabolites between cells. Transporters in the plasma membrane are required for transmembrane metabolite uptake into specific cell types, such as guard cells, pollen cells, and the sieve element/companion cell (SE/CC) complex that are symplasmically isolated. In addition, symplasmic domains of sink cells, for example, in fruit (2), require metabolite uptake transporters to support growth and development (for review, see Ref.3). Furthermore, events such as wounding, dehiscence, or programmed cell death will release metabolites into the cell wall space, and it is expected that surrounding cells have the capability to take up the released compounds.Although not yet functionally characterized, specific sugar transporter homologs are expressed during senescence (4), dehydration (5, 6), or pathogen attack (7) and may function in metabolite uptake. Arabidopsis encodes a wide array of metabolite transporters, around 100 potential metabolite transporters within the major facilitator superfamily (MFS) 1 alone. Available sequence data indicates that a similar situation exists in other plant species as well. Aside from the well characterized STP family of hexose transporters (8), very little information is available concerning transport activity of plant MFS members.Within the MFS, Arabidopsis encodes three groups of transporters that are closely related to the inositol permeases ITR1 and ITR2 from Schizosaccharomyces pombe (9) and Saccharomyces cerevisiae (10) and the xylose permease from Lactobacillus brevis (11). One group of four genes contains AtpGlcT (At5g16150), the plastidic glucose translocator (12). A second group of four genes is most similar to the plant vacuolar inositol permeases (Mitr1 and Mitr2)...

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Section: Discussionmentioning

confidence: 98%

“…The floral abscission zone consists of distinct layers of cells located where the floral organs such as petals, sepals, and anthers are shed after fertilization has occurred (33). During the abscission process glucanases and chitinases are induced, the middle lamella is dissolved and the cells eventually separate (33,34).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Transport Activity of Arabidopsis Sugar Alcohol Permease Homolog AtPLT5

Reinders

Panshyshyn

Ward

2005

Journal of Biological Chemistry

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“…4, A and C). Certain senescenceassociated WRKY genes, such as AtWRKY6, are expressed in floral tissues (Quirino et al, 1999), and maturation of the floral organ is also considered a senescence process (Bleecker and Patterson, 1997). Although the temporal expression pattern of GaWRKY1 in sepal and anther correlates with maturation of both organs, evidence that GaWRKY1 is involved in floral senescence is still lacking.…”

Section: Discussionmentioning

confidence: 99%

Characterization of GaWRKY1, a Cotton Transcription Factor That Regulates the Sesquiterpene Synthase Gene (+)-δ-Cadinene Synthase-A

et al. 2004

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The cotton (+)-δ-cadinene synthase (CAD1), a sesquiterpene cyclase, catalyzes a branch-point step leading to biosynthesis of sesquiterpene phytoalexins, including gossypol. CAD1-A is a member of CAD1 gene family, and its promoter contains a W-box palindrome with two reversely oriented TGAC repeats, which are the proposed binding sites of WRKY transcription factors. We isolated several WRKY cDNAs from Gossypium arboreum. One of them, GaWRKY1, encodes a protein containing a single WRKY domain and a putative N-terminal Leu zipper. Similar to genes encoding enzymes of cotton sesquiterpene pathway, GaWRKY1 was down-regulated in a glandless cotton cultivar that contained much less gossypol. GaWRKY1 showed a temporal and spatial pattern of expression comparable to that of CAD1-A in various aerial organs examined, including sepal, stigma, anther, and developing seeds. In suspension cells, expression of both GaWRKY1 and CAD1-A genes and biosynthesis of sesquiterpene aldehydes were strongly induced by a fungal elicitor preparation and methyl jasmonate. GaWRKY1 interacted with the 3× W-box derived from CAD1-A promoter in yeast (Saccharomyces cerevisiae) one-hybrid system and in vitro. Furthermore, in transgenic Arabidopsis plants, overexpression of GaWRKY1 highly activated the CAD1-A promoter, and transient assay in tobacco (Nicotiana tabacum) leaves demonstrated that W-box was required for this activation. These results suggest that GaWRKY1 participates in regulation of sesquiterpene biosynthesis in cotton, and CAD1-A is a target gene of this transcription factor.

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“…First, cauline leaves in the double mutant were serrated at their bases, as opposed to smooth in the wild type ( Figure 3D); second, floral organs failed to abscise ( Figure 3E). Abscission normally occurs after pollination and is a form of developmental programmed cell death that is promoted by ethylene and inhibited by auxin (reviewed in Bleecker and Patterson, 1997;Roberts et al, 2002). It is not yet known whether the abscission defect in bop1 bop2 reflects a structural defect in the abscission zone or an altered response to the hormonal regulation of this process.…”

Section: Bop1 and Bop2 Control Leaf Patterning And Floral Organ Abscimentioning

confidence: 99%

BLADE-ON-PETIOLE–Dependent Signaling Controls Leaf and Floral Patterning in Arabidopsis

et al. 2005

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NONEXPRESSOR OF PR GENES1 (NPR1) is a key regulator of the plant defense response known as systemic acquired resistance. Accumulation of the signal molecule salicylic acid (SA) leads to a change in intracellular redox potential, enabling NPR1 to enter the nucleus and interact with TGACG sequence-specific binding protein (TGA) transcription factors, which in turn bind to SA-responsive elements in the promoters of defense genes. Here, we show that two NPR1-like genes, BLADE-ON-PETIOLE1 (BOP1) and BOP2, function redundantly to control growth asymmetry, an important aspect of patterning in leaves and flowers. Phenotypes in the double mutant include leafy petioles, loss of floral organ abscission, and asymmetric flowers subtended by a bract. We demonstrate that BOP2 is localized to both the nucleus and the cytoplasm, but unlike NPR1, it is highly expressed in young floral meristems and in yeast interacts preferentially with the TGA transcription factor encoded by PERIANTHIA (PAN). In support of a biological relevance for this interaction, we show that bop1 bop2 and pan mutants share a pentamerous arrangement of first whorl floral organs, a patterning defect that is retained in bop1 bop2 pan triple mutants. Our data provide evidence that BOP proteins control patterning via direct interactions with TGA transcription factors and demonstrate that a signaling mechanism similar to that formally associated with plant defense is likely used for the control of developmental patterning.

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Last exit: senescence, abscission, and meristem arrest in Arabidopsis.

Cited by 387 publications

References 39 publications

Analysis of Transport Activity of Arabidopsis Sugar Alcohol Permease Homolog AtPLT5

Analysis of Transport Activity of Arabidopsis Sugar Alcohol Permease Homolog AtPLT5

Characterization of GaWRKY1, a Cotton Transcription Factor That Regulates the Sesquiterpene Synthase Gene (+)-δ-Cadinene Synthase-A

BLADE-ON-PETIOLE–Dependent Signaling Controls Leaf and Floral Patterning in Arabidopsis

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