Autoinhibition of indoleacetic acid transport in the shoots of two‐branched pea (<i>Pisum sativum</i>) plants and its relationship to correlative dominance

Li, Chunjian; Bangerth, F.

doi:10.1034/j.1399-3054.1999.106409.x

Cited by 110 publications

(117 citation statements)

References 32 publications

(26 reference statements)

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“…For example, another important correlation between auxin transport and bud growth is the lack of export of auxin from the inhibited bud. In two-branched pea plants, in which one shoot is inhibited by the other, the subordinate shoot is unable to export IAA unless the dominant shoot is decapitated (Morris, 1977;Li and Bangerth, 1999). This is the "autoinhibition at junctions effect," whereby apically derived auxin may control the export of bud-derived auxin into the stem's polar transport stream (Li and Bangerth, 1999).…”

Section: Auxin Transport Routes and The Regulation Of Bud Outgrowthmentioning

confidence: 99%

Auxin Acts in Xylem-Associated or Medullary Cells to Mediate Apical Dominance

2003

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A role for auxin in the regulation of shoot branching was described originally in the Thimann and Skoog model, which proposes that apically derived auxin is transported basipetally directly into the axillary buds, where it inhibits their growth. Subsequent observations in several species have shown that auxin does not enter axillary buds directly. We have found similar results in Arabidopsis. Grafting studies indicated that auxin acts in the aerial tissue; hence, the principal site of auxin action is the shoot. To delineate the site of auxin action, the wild-type AXR1 coding sequence, which is required for normal auxin sensitivity, was expressed under the control of several tissue-specific promoters in the auxin-resistant, highly branched axr1-12 mutant background. AXR1 expression in the xylem and interfascicular schlerenchyma was found to restore the mutant branching to wild-type levels in both intact plants and isolated nodes, whereas expression in the phloem did not. Therefore, apically derived auxin can suppress branching by acting in the xylem and interfascicular schlerenchyma, or in a subset of these cells.

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Section: Auxin Transport Routes and The Regulation Of Bud Outgrowthmentioning

confidence: 99%

Auxin Acts in Xylem-Associated or Medullary Cells to Mediate Apical Dominance

2003

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“…In the second model, SLs are proposed to act throughout the shoot to trigger clathrin-mediated endocytosis of the PIN1 auxin efflux carrier (Crawford et al, 2010;Shinohara et al, 2013). This hinders the establishment of positive feedback-driven, canalized auxin export from buds into the stem, which has been proposed to be required for the outgrowth of buds (Li and Bangerth, 1999;Prusinkiewicz et al, 2009;Crawford et al, 2010;Shinohara et al, 2013 very likely to act as a SL receptor, since it binds and hydrolyses the synthetic SL analog GR24 and is required for sensitivity to SL (Liu et al, 2009;Hamiaux et al, 2012;Waters et al, 2012;Kagiyama et al, 2013;Zhao et al, 2013;Chevalier et al, 2014). D14 acts in concert with the MAX2 F-box protein, which forms part of an SCFtype ubiquitin ligase complex (Stirnberg et al, 2007;Hamiaux et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SMAX1-LIKE7 signals from the nucleus to regulate shoot development in Arabidopsis via partially EAR motif-independent mechanisms

et al. 2016

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Strigolactones (SLs) are hormonal signals that regulate multiple aspects of shoot architecture, including shoot branching. Like many plant hormonal signaling systems, SLs act by promoting ubiquitination of target proteins and their subsequent proteasome-mediated degradation. Recently, SMXL6, SMXL7, and SMXL8, members of the SMAX1-LIKE (SMXL) family of chaperonin-like proteins, have been identified as proteolytic targets of SL signaling in Arabidopsis thaliana. However, the mechanisms by which these proteins regulate downstream events remain largely unclear. Here, we show that SMXL7 functions in the nucleus, as does the SL receptor, DWARF14 (D14). We show that nucleus-localized D14 can physically interact with both SMXL7 and the MAX2 F-box protein in a SL-dependent manner and that disruption of specific conserved domains in SMXL7 affects its localization, SL-induced degradation, and activity. By expressing and overexpressing these SMXL7 protein variants, we show that shoot tissues are broadly sensitive to SMXL7 activity, but degradation normally buffers the effect of increasing SMXL7 expression. SMXL7 contains a well-conserved EAR (ETHYLENE-RESPONSE FACTOR Amphiphilic Repression) motif, which contributes to, but is not essential for, SMXL7 functionality. Intriguingly, different developmental processes show differential sensitivity to the loss of the EAR motif, raising the possibility that there may be several distinct mechanisms at play downstream of SMXL7. INTRODUCTIONShoot system architectural characteristics strongly influence the productivity of many crop species, and architectural traits have been selected in both historical and contemporary breeding schemes. Understanding the mechanisms that regulate shoot architecture, and its environmental responsiveness, is therefore an important goal for plant research. It is well established that long-distance hormonal signals, including auxin, cytokinin, and strigolactone (SL), are key regulators of shoot architecture and allow communication both within the shoot system and between the shoot and root . For instance, cytokinin produced in the root system in response to the availability of nitrate ions is systemically transported to the shoot, where it promotes branching (Kiba et al., 2011; Müller et al., 2015). Similarly, root-derived SL plays a key role in negatively regulating branching in response to low phosphate availability in the rhizosphere (Kohlen et al., 2011). However, our understanding of the molecular mechanisms that act downstream of these hormones to alter developmental processes in the shoot is currently limited. This is particularly true of SLs. Analysis of the phenotypes of SL biosynthesis and signaling mutants has revealed roles for SLs in the regulation of shoot branching, branching angle, plant height, stem thickness, and leaf blade elongation . The role of SLs in regulating shoot branching has been intensively studied, resulting in two contrasting, nonexclusive models for their mode of action. In the first, SLs are proposed to act locally in axill...

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“…SLs, when directly applied to buds, can inhibit them (Gomez-Roldan et al, 2008;Brewer et al, 2009), evidence that contributed to the proposal that they may be acting as second messengers for auxin, relaying the inhibitory signal from the stem to buds. Alternatively, it has been proposed that PAT in the main stem can inhibit bud activity through influencing stem sink strength for auxin, thereby affecting the crucial establishment of auxin export from the bud and thus bud activation (Li and Bangerth, 1999;Bennett et al, 2006;Prusinkiewicz et al, 2009;Balla et al, 2011). SL action in this case would be through systemically dampening auxin transport canalization.…”

Section: Salix Spp Bud Response To Strigolactone and Auxinmentioning

confidence: 99%

“…Auxin transport canalization involves an initial flow of auxin from a source to a sink, which both upregulates and polarizes auxin transport in the direction of this initial flow, gradually "canalizing" it into files of cells with high auxin transport capacity toward the sink (Sachs, 1981). This process strongly correlates with bud activation (Morris, 1977;Li and Bangerth, 1999;Prusinkiewicz et al, 2009;Balla et al, 2011).…”

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confidence: 99%

Using Arabidopsis to Study Shoot Branching in Biomass Willow

et al. 2013

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The success of the short-rotation coppice system in biomass willow (Salix spp.) relies on the activity of the shoot-producing meristems found on the coppice stool. However, the regulation of the activity of these meristems is poorly understood. In contrast, our knowledge of the mechanisms behind axillary meristem regulation in Arabidopsis (Arabidopsis thaliana) has grown rapidly in the past few years through the exploitation of integrated physiological, genetic, and molecular assays. Here, we demonstrate that these assays can be directly transferred to study the control of bud activation in biomass willow and to assess similarities with the known hormone regulatory system in Arabidopsis. Bud hormone response was found to be qualitatively remarkably similar in Salix spp. and Arabidopsis. These similarities led us to test whether Arabidopsis hormone mutants could be used to assess allelic variation in the cognate Salix spp. hormone genes. Allelic differences in Salix spp. strigolactone genes were observed using this approach. These results demonstrate that both knowledge and assays from Arabidopsis axillary meristem biology can be successfully applied to Salix spp. and can increase our understanding of a fundamental aspect of short-rotation coppice biomass production, allowing more targeted breeding.

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Autoinhibition of indoleacetic acid transport in the shoots of two‐branched pea (Pisum sativum) plants and its relationship to correlative dominance

Cited by 110 publications

References 32 publications

Auxin Acts in Xylem-Associated or Medullary Cells to Mediate Apical Dominance

Auxin Acts in Xylem-Associated or Medullary Cells to Mediate Apical Dominance

SMAX1-LIKE7 signals from the nucleus to regulate shoot development in Arabidopsis via partially EAR motif-independent mechanisms

Using Arabidopsis to Study Shoot Branching in Biomass Willow

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