13 results on '"Rahko, Hanna"'
Search Results
2. A core mechanism for specifying root vascular pattern can replicate the anatomical variation seen in diverse plant species
- Author
-
Mellor, Nathan, Vaughan-Hirsch, John, Help-Rinta-Rahko, Hanna, Miyashima, Shunsuke, Campilho, Ana, King, John R., and Bishopp, Anthony
- Subjects
fungi ,food and beverages - Abstract
Pattern formation is typically controlled through the interaction between molecular signals within a given tissue. During early embryonic development, roots of the model plant Arabidopsis thaliana have a radially symmetric pattern, but a heterogeneous input of the hormone auxin from the two cotyledons forces the vascular cylinder to develop a diarch pattern with two xylem poles. Molecular analyses and mathematical approaches have uncovered the regulatory circuit that propagates this initial auxin signal into a stable cellular pattern. The diarch pattern seen in Arabidopsis is relatively uncommon among flowering plants, with most species having between three and eight xylem poles. Here, we have used multiscale mathematical modelling to demonstrate that this regulatory module does not require a heterogeneous auxin input to specify the vascular pattern. Instead, the pattern can emerge dynamically, with its final form dependent upon spatial constraints and growth. The predictions of our simulations compare to experimental observations of xylem pole number across a range of species, as well as in transgenic systems in Arabidopsis in which we manipulate the size of the vascular cylinder. By considering the spatial constraints, our model is able to explain much of the diversity seen in different flowering plant species.
- Published
- 2019
3. Coded Acoustic Microscopy to Study Wood Mechanics and Development
- Author
-
Hyvonen, Jere, primary, Serra, Juan Alonso, additional, Merilainen, Antti, additional, Help-Rinta-Rahko, Hanna, additional, Nieminen, Kaisa, additional, Salmi, Ari, additional, Svedstrom, Kirsi, additional, Helariutta, Yrjo, additional, and Haeggstrom, Edward, additional
- Published
- 2019
- Full Text
- View/download PDF
4. ELIMÄKI locus is required for mechanosensing and proprioception in birch trees
- Author
-
Alonso-Serra, Juan, primary, Shi, Xueping, additional, Peaucelle, Alexis, additional, Rastas, Pasi, additional, Bourdon, Matthieu, additional, Immanen, Juha, additional, Takahashi, Junko, additional, Koivula, Hanna, additional, Eswaran, Gugan, additional, Muranen, Sampo, additional, Help-Rinta-Rahko, Hanna, additional, Smolander, Olli-Pekka, additional, Su, Chang, additional, Safronov, Omid, additional, Gerber, Lorenz, additional, Salojärvi, Jarkko, additional, Hagqvist, Risto, additional, Mähonen, Ari-Pekka, additional, Nieminen, Kaisa, additional, and Helariutta, Ykä, additional
- Published
- 2019
- Full Text
- View/download PDF
5. TONEWOOD PROJECT – WOOD USED IN ELECTRIC GUITARS
- Author
-
Ahvenainen, Patrik, Viljanen, Mira, Mäkinen, Henrik, Help-Rinta-Rahko, Hanna, Suhonen, Heikki, and Huotari, Simo
- Published
- 2017
- Full Text
- View/download PDF
6. The interaction of auxin and cytokinin signalling regulates primary root procambial patterning, xylem cell fate and differentiation in Arabidopsis thaliana
- Author
-
Help-Rinta-Rahko, Hanna, University of Helsinki, Faculty of Agriculture and Forestry, Department of Agricultural Sciences, Institute of Biotechnology, Faculty of Biosciences, Department of Biological and Environmental Sciences, Helsingin yliopisto, maatalous-metsätieteellinen tiedekunta, maataloustieteiden laitos, Helsingfors universitet, agrikultur-forstvetenskapliga fakulteten, institutionen för lantsbruksvetenskaper, Geldner, Niko, and Helariutta, Yrjö
- Subjects
plant Molecular and Developmental Biology - Abstract
The interaction of auxin and cytokinin signalling regulates primary root procambial patterning, xylem cell fate and differentiation in Arabidopsis thaliana. Plants contribute to the Earth s atmosphere by binding carbon dioxide and releasing oxygen. Trees produce biomass, which is a renewable source of energy. The Arabidopsis root vasculature is a good model system for studying biomass formation, as it contains the same cell types that are also found in trees: xylem, phloem and intervening pluripotent procambial cells. In Arabidopsis thaliana roots, these cells arise from stem cells within the root meristem. The wild type root radial pattern is bisymmetric, and the regulation of xylem formation is controlled by phytohormones, especially auxin and cytokinin. Our findings show that the vascular pattern is set by a symmetry-breaking event during embryogenesis and is initiated by auxin accumulation and signalling at the cotyledon initials. As the embryo grows, the high auxin signalling promotes the expression of AHP6. Upregulation of AHP6 in specific cells leads to inhibition of cytokinin signalling and might be a key factor in symmetry breakage. Mutants with altered cotyledon numbers or altered cotyledon anatomy fail to establish the bisymmetric pattern and often show altered root symmetry. In growing roots, the bisymmetric pattern is actively reinforced by polar auxin transport and long distance cytokinin transport/translocation from the apical parts of the plant. Cytokinin movement via the phloem and unloading at the root apical meristem promotes cytokinin signalling in the procambial cells in the proximal meristem. Both cytokinin and auxin are required during root procambial patterning, and the interaction of these two phytohormones is mutually inhibitory. According to our model (described in the first part of this thesis), auxin signalling is critical for protoxylem identity formation. In turn, the results from the procambial re-patterning experiments (second part of this thesis) show that cytokinin is the key hormone in promoting cell proliferation in the proximal meristem. Epistasis experiments illustrate that a fine balance between these two hormones affects the fate of all vascular cells. We are beginning to understand the complexity and interdependencies of signalling pathway interactions during proximal meristem vascular patterning, yet the temporal aspect is still largely unexplored. In the last part of this thesis, I discuss the role ROS signalling might have in stele patterning and temporal regulation of programmed cell death. While our published GRI-MC9-PRK5 module might not be directly linked to primary root proximal meristem procambial patterning, one cannot exclude the possibility that it might be required in the final stages of protoxylem differentiation or that a similar signalling mechanism could regulate initial stele patterning and meristem growth dynamics. This thesis describes the auxin-cytokinin interaction in vascular initial patterning and the mechanism by which the hormonal signalling domains are maintained in the proximal meristem. The unpublished data demonstrate how procambial cells can be manipulated to generate new tissues by affecting the homeostasis of auxin and cytokinin signalling. The last part of the thesis describes a cell death signalling module and speculates that it (or similar module) might be involved with primary root meristem maturation. Auksiini-sytokiniini-signaloinnin vuorovaikutus Arabidopsis thalianan primääri-juuren johtojänteen solutyyppien identiteetin muodostumisen ja puusolukon erilaistumisen säätelyssä. Kasvit vaikuttavat maapallon ilmakehän koostumukseen sitomalla itseensä hiilidioksidia sekä vapauttamalla happea. Puut tuottavat biomassaa, joka on uusiutuva energianlähde. Puusolukon muodostumista säätelevät kasvihormonit, erityisesti auksiini ja sytokiniini. Arabidopsis thalianan eli lituruohon juuren johtojänne on hyvä malli puunmuodostuksen tutkimiselle, sillä se sisältää samat solutyypit kuin suuremmat puuvartiset kasvit. Nämä keskeiset solutyyppit ovat ksyleemi (puu), nila ja jälsi, joka sijaitsee ksyleemi- ja nilasolujen välissä. Nämä solutyypit kehittyvät lituruohon juurissa kärkikasvupisteiden kantasoluista. Villityypin lituruohon johtojänne on rakenteeltaan bisymmetrinen. Johtojänteen rakenne muodostuu varhain alkiokehityksen aikana, ja juurten symmetria määräytyy verson sirkkalehtien perusteella. Auksiini akkumuloituu sirkkalehtien aiheisiin. Kun alkio kasvaa suuremmaksi, korkea auksiini-pitoisuus edistää AHP6-geenin ekspressiota sirkkalehdissä ja alkion juuren johtojänteessä. Tämä soluspesifinen AHP6 ilmentyminen johtaa sytokiniinisignaloinnin inhibitioon, mikä on kriittistä bisymmetrian muodostumiselle. Mutanteilla joiden sirkkalehtien lukumäärä tai muoto poikkeaa normaalista, on havaittu ongelmia sekä bisymmetrisen rakenteen muodostumisessa alkionkehityksen aikana, että juuren normaalin rakenteen ylläpidossa itämisen jälkeen. Kasvavien juurten rakennetta pidetään aktiivisesti yllä auksiinin ja sytokiniinin kuljetuksella versoista juuriin. Sytokiniinin liikkuminen nilan mahlavirtauksen mukana juurten kärkiin edistää sytokiniinisignalointia kärkikasvupisteen kantasoluissa ja niiden tytärsoluissa. Sekä sytokiniinia että auksiinia tarvitaan johtosolukon erilaistumiseen ja nämä hormonit vaikuttavat toisiinsa inhiboivasti. Esittämämme mallin mukaan (kuvattu ensimmäisessä osiossa) auksiinisignalointi on kriittistä protoksyleemin identiteetin muodostumiselle. Sytokiniini on puolestaan tärkeää juuren kärkikasvupisteen solujen jakautumisen ja erilaistumattomien jälsisolujen identiteetille, kuten tulokset johtojänteen uudelleen-järjestäytymiskokeista osoittavat (väitöskirjan toisessa osuudessa). Näiden kahden hormonin välinen epistasia säätelee kaikkien johtojänteen solujen kehitystä. Tämän väitöskirjan viimeinen osuus keskittyy happiradikaali-signaloinnin ja kontrolloidun solukuoleman rooliin juuren meristeemin kehityksessä. Vaikka julkaisemamme GRI-MC9-PRK5-moduuli ei vaikuta liittyvän kärkikasvupisteen kantasolujen identiteetin ja johtojänteen rakenteen säätelyyn, on mahdollista että sitä tarvitaan protoksyleemin erilaistumisessa myöhemmissä vaiheissa. Väitöskirjan viimeisessä osuudessa spekuloidaan sillä, mikä rooli solukuolemaan liittyvällä signaloinnilla on juuren kärkikasvupisteen kypsymisen säätelyssä. Tämä väitöskirjatyö havainnollistaa auksiini-sytokiniini-vuorovaikutuksen roolia johtojänteen kantasolujen identiteetin muodostumisessa ja mekanismin, jolla hormonisignalointidomeenit vuorovaikuttavat toisiinsa. Tulokset osoittavat, että juuren rakennetta voidaan muuttaa keinotekoisesti manipuloimalla auksiini-sytokiniini hormonisignalointia. Ymmärryksemme eri hormonisignalointireittien monimutkaisuudesta ja niiden välisistä vuorovaikutuksista juuren johtojänteen eri solutyyppien identiteettien muodostumisessa on lisääntynyt merkittävästi viime vuosien aikana, mutta juuren kärkikasvupisteen eri solujen kypsymisen ajallinen säätely kaipaa lisää tutkimusta.
- Published
- 2016
7. GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis
- Author
-
Wrzaczek, Michael, Vainonen, Julia P., Stael, Simon, Tsiatsiani, Liana, Help-Rinta-Rahko, Hanna, Gauthier, Adrien, Kaufholdt, David, Bollhoner, Benjamin, Lamminmaki, Airi, Staes, An, Gevaert, Kris, Hannele Tuominen, Breusegem, Frank, Helariutta, Yka, Kangasjarvi, Jaakko, Helariutta, Yrjo [0000-0002-7287-8459], and Apollo - University of Cambridge Repository
- Subjects
receptor‐like kinase ,Cell Death ,Arabidopsis Proteins ,fungi ,Cell Membrane ,Arabidopsis ,protease ,secreted protein ,ligand ,Protein Structure, Tertiary ,Oxidative Stress ,Caspases ,Peptides ,Protein Kinases ,Protein Binding ,Signal Transduction - Abstract
Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor.
- Published
- 2015
8. Parsimonious Model of Vascular Patterning Links Transverse Hormone Fluxes to Lateral Root Initiation
- Author
-
University of Helsinki, Institute of Biotechnology, el-Showk, Sedeer, Help-Rinta-Rahko, Hanna, Blomster, Tiina, Siligato, Riccardo, Maree, Athanasius F. M., Mähonen, Ari Pekka, Grieneisen, Veronica A., University of Helsinki, Institute of Biotechnology, el-Showk, Sedeer, Help-Rinta-Rahko, Hanna, Blomster, Tiina, Siligato, Riccardo, Maree, Athanasius F. M., Mähonen, Ari Pekka, and Grieneisen, Veronica A.
- Abstract
An auxin maximum is positioned along the xylem axis of the Arabidopsis root tip. The pattern depends on mutual feedback between auxin and cytokinins mediated by the PIN class of auxin efflux transporters and AHP6, an inhibitor of cytokinin signalling. This interaction has been proposed to regulate the size and the position of the hormones' respective signalling domains and specify distinct boundaries between them. To understand the dynamics of this regulatory network, we implemented a parsimonious computational model of auxin transport that considers hormonal regulation of the auxin transporters within a spatial context, explicitly taking into account cell shape and polarity and the presence of cell walls. Our analysis reveals that an informative spatial pattern in cytokinin levels generated by diffusion is a theoretically unlikely scenario. Furthermore, our model shows that such a pattern is not required for correct and robust auxin patterning. Instead, auxin-dependent modifications of cytokinin response, rather than variations in cytokinin levels, allow for the necessary feedbacks, which can amplify and stabilise the auxin maximum. Our simulations demonstrate the importance of hormonal regulation of auxin efflux for pattern robustness. While involvement of the PIN proteins in vascular patterning is well established, we predict and experimentally verify a role of AUX1 and LAX1/2 auxin influx transporters in this process. Furthermore, we show that polar localisation of PIN1 generates an auxin flux circuit that not only stabilises the accumulation of auxin within the xylem axis, but also provides a mechanism for auxin to accumulate specifically in the xylem-pole pericycle cells, an important early step in lateral root initiation. The model also revealed that pericycle cells on opposite xylem poles compete for auxin accumulation, consistent with the observation that lateral roots are not initiated opposite to each other.
- Published
- 2015
9. Parsimonious Model of Vascular Patterning Links Transverse Hormone Fluxes to Lateral Root Initiation: Auxin Leads the Way, while Cytokinin Levels Out
- Author
-
el-Showk, Sedeer, primary, Help-Rinta-Rahko, Hanna, additional, Blomster, Tiina, additional, Siligato, Riccardo, additional, Marée, Athanasius F. M., additional, Mähönen, Ari Pekka, additional, and Grieneisen, Verônica A., additional
- Published
- 2015
- Full Text
- View/download PDF
10. GRIM REAPER peptide binds to receptor kinase PRK 5 to trigger cell death in Arabidopsis
- Author
-
Wrzaczek, Michael, primary, Vainonen, Julia P, additional, Stael, Simon, additional, Tsiatsiani, Liana, additional, Help‐Rinta‐Rahko, Hanna, additional, Gauthier, Adrien, additional, Kaufholdt, David, additional, Bollhöner, Benjamin, additional, Lamminmäki, Airi, additional, Staes, An, additional, Gevaert, Kris, additional, Tuominen, Hannele, additional, Van Breusegem, Frank, additional, Helariutta, Ykä, additional, and Kangasjärvi, Jaakko, additional
- Published
- 2014
- Full Text
- View/download PDF
11. Frans Ferdinand Ahlmanin ruotsalais-suomalaisessa sanakirjassaan (1865) suomen kieleen lainaamien vierassanojen ensiesiintymät
- Author
-
Rahko, Hanna and TY. SYKL.
- Subjects
ruotsin kieli ,vierassanat ,sanakirjat ,suomenkieli ,Ahlman, Frans Ferdinand - Published
- 2005
12. A core mechanism for specifying root vascular patterning can replicate the anatomical variation seen in diverse plant species.
- Author
-
Mellor N, Vaughan-Hirsch J, Kümpers BMC, Help-Rinta-Rahko H, Miyashima S, Mähönen AP, Campilho A, King JR, and Bishopp A
- Subjects
- Arabidopsis genetics, Arabidopsis Proteins physiology, Flowers genetics, Indoleacetic Acids, Models, Biological, Plant Growth Regulators physiology, Signal Transduction, Species Specificity, Stochastic Processes, Xylem physiology, Arabidopsis growth & development, Gene Expression Regulation, Plant, Plant Roots anatomy & histology
- Abstract
Pattern formation is typically controlled through the interaction between molecular signals within a given tissue. During early embryonic development, roots of the model plant Arabidopsis thaliana have a radially symmetric pattern, but a heterogeneous input of the hormone auxin from the two cotyledons forces the vascular cylinder to develop a diarch pattern with two xylem poles. Molecular analyses and mathematical approaches have uncovered the regulatory circuit that propagates this initial auxin signal into a stable cellular pattern. The diarch pattern seen in Arabidopsis is relatively uncommon among flowering plants, with most species having between three and eight xylem poles. Here, we have used multiscale mathematical modelling to demonstrate that this regulatory module does not require a heterogeneous auxin input to specify the vascular pattern. Instead, the pattern can emerge dynamically, with its final form dependent upon spatial constraints and growth. The predictions of our simulations compare to experimental observations of xylem pole number across a range of species, as well as in transgenic systems in Arabidopsis in which we manipulate the size of the vascular cylinder. By considering the spatial constraints, our model is able to explain much of the diversity seen in different flowering plant species., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)
- Published
- 2019
- Full Text
- View/download PDF
13. GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis.
- Author
-
Wrzaczek M, Vainonen JP, Stael S, Tsiatsiani L, Help-Rinta-Rahko H, Gauthier A, Kaufholdt D, Bollhöner B, Lamminmäki A, Staes A, Gevaert K, Tuominen H, Van Breusegem F, Helariutta Y, and Kangasjärvi J
- Subjects
- Arabidopsis genetics, Arabidopsis Proteins genetics, Caspases genetics, Cell Death physiology, Cell Membrane genetics, Cell Membrane metabolism, Peptides genetics, Protein Binding physiology, Protein Kinases genetics, Protein Structure, Tertiary, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Caspases metabolism, Oxidative Stress physiology, Peptides metabolism, Protein Kinases metabolism, Signal Transduction physiology
- Abstract
Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor., (© 2014 The Authors.)
- Published
- 2015
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.