| 1. |
- Bhatia, Neha, et al.
(författare)
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Auxin Acts through MONOPTEROS to Regulate Plant Cell Polarity and Pattern Phyllotaxis
- 2016
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 26:23, s. 3202-3208
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Tidskriftsartikel (refereegranskat)abstract
- The periodic formation of plant organs such as leaves and flowers gives rise to intricate patterns that have fascinated biologists and mathematicians alike for hundreds of years [1]. The plant hormone auxin plays a central role in establishing these patterns by promoting organ formation at sites where it accumulates due to its polar, cell-to-cell transport [2-6]. Although experimental evidence as well as modeling suggest that feedback from auxin to its transport direction may help specify phyllotactic patterns [7-12], the nature of this feedback remains unclear [13]. Here we reveal that polarization of the auxin efflux carrier PIN-FORMED 1 (PIN1) is regulated by the auxin response transcription factor MONOPTEROS (MP) [14]. We find that in the shoot, cell polarity patterns follow MP expression, which in turn follows auxin distribution patterns. By perturbing MP activity both globally and locally, we show that localized MP activity is necessary for the generation of polarity convergence patterns and that localized MP expression is sufficient to instruct PIN1 polarity directions non-cell autonomously, toward MP-expressing cells. By expressing MP in the epidermis of mp mutants, we further show that although MP activity in a single-cell layer is sufficient to promote polarity convergence patterns, MP in sub-epidermal tissues helps anchor these polarity patterns to the underlying cells. Overall, our findings reveal a patterning module in plants that determines organ position by orienting transport of the hormone auxin toward cells with high levels of MP-mediated auxin signaling. We propose that this feedback process acts broadly to generate periodic plant architectures.
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| 2. |
- Bhatia, Neha, et al.
(författare)
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Quantitative analysis of auxin sensing in leaf primordia argues against proposed role in regulating leaf dorsoventrality
- 2019
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Ingår i: eLife. - 2050-084X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Dorsoventrality in leaves has been shown to depend on the pre-patterned expression of KANADI and HD-ZIPIII genes within the plant shoot apical meristem (SAM). However, it has also been proposed that asymmetric auxin levels within initiating leaves help establish leaf polarity, based in part on observations of the DII auxin sensor. By analyzing and quantifying the expression of the R2D2 auxin sensor, we find that there is no obvious asymmetry in auxin levels during Arabidopsis leaf development. We further show that the mDII control sensor also exhibits an asymmetry in expression in developing leaf primordia early on, while it becomes more symmetric at a later developmental stage as reported previously. Together with other recent findings, our results argue against the importance of auxin asymmetry in establishing leaf polarity.
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| 3. |
- Caggiano, Monica Pia, et al.
(författare)
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Cell type boundaries organize plant development
- 2017
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Ingår i: eLife. - 2050-084X.
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Tidskriftsartikel (refereegranskat)abstract
- In plants the dorsoventral boundary of leaves defines an axis of symmetry through thecentre of the organ separating the top (dorsal) and bottom (ventral) tissues. Although thepositioning of this boundary is critical for leaf morphogenesis, how the boundary is established andhow it influences development remains unclear. Using live-imaging and perturbation experimentswe show that leaf orientation, morphology and position are pre-patterned by HD-ZIPIII and KANgene expression in the shoot, leading to a model in which dorsoventral genes coordinate toregulate plant development by localizing auxin response between their expression domains.However we also find that auxin levels feedback on dorsoventral patterning by spatially organizingHD-ZIPIII and KAN expression in the shoot periphery. By demonstrating that the regulation ofthese genes by auxin also governs their response to wounds, our results also provide aparsimonious explanation for the influence of wounds on leaf dorsoventrality.
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| 4. |
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| 5. |
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| 6. |
- Heisler, Marcus, et al.
(författare)
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Computer modeling of plant development
- 2006
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Ingår i: Journal of Plant Growth Regulation. - : Springer Science and Business Media LLC. - 0721-7595 .- 1435-8107. ; 25, s. 267-269
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Heisler, Marcus G., et al.
(författare)
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Alignment between PIN1 Polarity and Microtubule Orientation in the Shoot Apical Meristem Reveals a Tight Coupling between Morphogenesis and Auxin Transport
- 2010
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Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1545-7885. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Morphogenesis during multicellular development is regulated by intercellular signaling molecules as well as by the mechanical properties of individual cells. In particular, normal patterns of organogenesis in plants require coordination between growth direction and growth magnitude. How this is achieved remains unclear. Here we show that in Arabidopsis thaliana, auxin patterning and cellular growth are linked through a correlated pattern of auxin efflux carrier localization and cortical microtubule orientation. Our experiments reveal that both PIN1 localization and microtubule array orientation are likely to respond to a shared upstream regulator that appears to be biomechanical in nature. Lastly, through mathematical modeling we show that such a biophysical coupling could mediate the feedback loop between auxin and its transport that underlies plant phyllotaxis.
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| 8. |
- Heisler, Marcus G., et al.
(författare)
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Context-specific functions of transcription factors controlling plant development : From leaves to flowers
- 2022
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Ingår i: Current Opinion in Plant Biology. - : Elsevier BV. - 1369-5266. ; 69
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Forskningsöversikt (refereegranskat)abstract
- Plant development is regulated by transcription factors that often act in more than one process and stage of development. Yet the molecular mechanisms that govern the functional diversity and specificity of these proteins remains far from understood. Flower development provides an ideal context to study these mechanisms since the development of distinct floral organs depends on similar but distinct combinations of transcriptional regulators. Recent work also highlights the importance of leaf polarity regulators as additional key factors in flower initiation, floral organ morphogenesis, and possibly floral organ positioning. A detailed understanding of how these factors work in combination will enable us to address outstanding questions in flower development including how distinct shapes and positions of floral organs are generated. Experimental approaches and computer-based modeling will be required to characterize gene-regulatory networks at the level of single cells.
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| 9. |
- Heisler, Marcus G., et al.
(författare)
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Modelling meristem development in plants
- 2007
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Ingår i: Current Opinion in Plant Biology. - : Elsevier BV. - 1369-5266. ; 10:1, s. 92-97
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Forskningsöversikt (refereegranskat)abstract
- Meristems continually supply new cells for post-embryonic plant development and coordinate the initiation of new organs, such as leaves and flowers. Meristem function is regulated by a large and interconnected dynamic system that includes transcription networks, intercellular protein signalling, polarized transport of hormones and a constantly changing cellular topology. Mathematical modelling, in which the dynamics of a system are simulated using explicitly defined interactions, can serve as a powerful tool for examining the expected behaviour of such a system given our present knowledge and assumptions. Modelling can also help to investigate new hypotheses in silico both to validate ideas and to obtain inspiration for new experiments. Several recent studies have used new molecular data together with modelling and computational techniques to investigate meristem function.
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| 10. |
- Heisler, Marcus, et al.
(författare)
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Modeling auxin transport and plant development
- 2006
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Ingår i: Journal of Plant Growth Regulation. - : Springer Science and Business Media LLC. - 0721-7595 .- 1435-8107. ; 25, s. 302-312
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Tidskriftsartikel (refereegranskat)abstract
- The plant hormone auxin plays a critical role in plant development. Central to its function is its distribution in plant tissues, which is, in turn, largely shaped by intercellular polar transport processes. Auxin transport relies on diffusive uptake as well as carrier-mediated transport via influx and efflux carriers. Mathematical models have been used to both refine our theoretical understanding of these processes and to test new hypotheses regarding the localization of efflux carriers to understand auxin patterning at the tissue level. Here we review models for auxin transport and how they have been applied to patterning processes, including the elaboration of plant vasculature and primordium positioning. Second, we investigate the possible role of auxin influx carriers such as AUX1 in patterning auxin in the shoot meristem. We find that AUX1 and its relatives are likely to play a crucial role in maintaining high auxin levels in the meristem epidermis. We also show that auxin influx carriers may play an important role in stabilizing auxin distribution patterns generated by auxin-gradient type models for phyllotaxis.
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