scholarly journals Auxin minimum triggers the developmental switch from cell division to cell differentiation in the Arabidopsis root

2017 ◽  
Vol 114 (36) ◽  
pp. E7641-E7649 ◽  
Author(s):  
Riccardo Di Mambro ◽  
Micol De Ruvo ◽  
Elena Pacifici ◽  
Elena Salvi ◽  
Rosangela Sozzani ◽  
...  
Keyword(s):  
Cell Division ◽  
Auxin Transport ◽  
Positional Information ◽  
Polar Auxin Transport ◽  
Arabidopsis Root ◽  
Polar Transport ◽  
Stringent Control ◽  
Auxin Polar Transport ◽  
Multicellular Organisms ◽  
Developmental Switch

In multicellular organisms, a stringent control of the transition between cell division and differentiation is crucial for correct tissue and organ development. In the Arabidopsis root, the boundary between dividing and differentiating cells is positioned by the antagonistic interaction of the hormones auxin and cytokinin. Cytokinin affects polar auxin transport, but how this impacts the positional information required to establish this tissue boundary, is still unknown. By combining computational modeling with molecular genetics, we show that boundary formation is dependent on cytokinin’s control on auxin polar transport and degradation. The regulation of both processes shapes the auxin profile in a well-defined auxin minimum. This auxin minimum positions the boundary between dividing and differentiating cells, acting as a trigger for this developmental transition, thus controlling meristem size.

Auxin Transport Inhibitors. II. 2-(1-Pyrenol)Benzoic Acid, a Potent Inhibitor of Polar Auxin Transport

1977 ◽  
Vol 4 (3) ◽  
pp. 321 ◽  
Author(s):  
GF Katekar ◽  
AE Geissler
Keyword(s):  
Benzoic Acid ◽  
Auxin Transport ◽  
Indoleacetic Acid ◽  
Potent Inhibitor ◽  
Polar Auxin Transport ◽  
Active Inhibitor ◽  
Polar Transport ◽  
Highly Active ◽  
Transport Inhibitors ◽  
Auxin Transport Inhibitors

2-(1-Pyrenoyl)benzoic acid is shown to be a highly active inhibitor of auxin transport by its ability to prevent the polar transport of indoleacetic acid in bean petioles. It is comparable in activity to other known auxin transport inhibitors, and also affects apical dominance and the geotropic and phototropic responses.

scholarly journals Cytokinins and polar transport of auxin in axillary pea buds

2010 ◽  
Vol 58 (4) ◽  
pp. 79-88 ◽  
Author(s):  
Petr Kalousek ◽  
Dagmar Buchtová ◽  
Jozef Balla ◽  
Vilém Reinöhl ◽  
Stanislav Procházka
Keyword(s):  
Apical Dominance ◽  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Axillary Buds ◽  
Polar Transport ◽  
Exogenous Application ◽  
Intact Plants ◽  
Key Factor ◽  
Basal Pole ◽  
Auxin Carrier

The influence of cytokinin on auxin transport during release of axillary buds from apical dominance was studied. Expression of auxin-carrier coding genes PsAUX1 (AUXIN RESISTANT 1) and PsPIN1 (PIN-FORMED 1) was explored in axillary buds of the 2nd node of 7-day pea plants (Pisum sativum L.) cv. Vladan after decapitation or after exogenous application of benzyladenine (6-benzylaminopurine) onto axillary buds of intact plants. Localization of the PsPIN1 protein, the key factor for polar transport of auxin in axillary buds, was visualised by immunohistochemistry. After exogenous application of cytokinin the expression of PsAUX1 and PsPIN1 rapidly increased with a simultaneous rapid decrease in PsDRM1 and PsAD1 expression – genes related to bud dormancy. The same changes in expression were observed after decapitation, however they were markedly slower. The PsPIN1 auxin efflux carrier in the inhibited axillary buds of intact plants was localised in a non-polar manner. After exogenous application of cytokinin gradual polarisation of the PsPIN1 protein occurred on the basal pole of polar auxin transport competent cells. Despite the fact that direct auxin application to buds of intact plants led to an increase in PsAUX1 and PsPIN1 expression, the buds remained dormant (non-growing) what was accompanied by persistent expression of the dormancy markers PsDRM1 and PsAD1. The results indicate a possible effect of cytokinins on biosynthesis, and/or transport of auxin in axillary buds and they highlight the importance of auxin-cytokinin crosstalk in the regulation of bud outgrowth after breaking of apical dominance.

scholarly journals PIN2 Polarity Establishment in Arabidopsis in the Absence of an Intact Cytoskeleton

Biomolecules ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 222 ◽  
Author(s):  
Matouš Glanc ◽  
Matyáš Fendrych ◽  
Jiří Friml
Keyword(s):  
Subcellular Localization ◽  
Live Cell Imaging ◽  
Auxin Transport ◽  
Imaging Techniques ◽  
Actin Microfilaments ◽  
Coordinated Development ◽  
Arabidopsis Root ◽  
Polar Localization ◽  
Multicellular Organisms ◽  
Endomembrane Trafficking

Cell polarity is crucial for the coordinated development of all multicellular organisms. In plants, this is exemplified by the PIN-FORMED (PIN) efflux carriers of the phytohormone auxin: The polar subcellular localization of the PINs is instructive to the directional intercellular auxin transport, and thus to a plethora of auxin-regulated growth and developmental processes. Despite its importance, the regulation of PIN polar subcellular localization remains poorly understood. Here, we have employed advanced live-cell imaging techniques to study the roles of microtubules and actin microfilaments in the establishment of apical polar localization of PIN2 in the epidermis of the Arabidopsis root meristem. We report that apical PIN2 polarity requires neither intact actin microfilaments nor microtubules, suggesting that the primary spatial cue for polar PIN distribution is likely independent of cytoskeleton-guided endomembrane trafficking.

scholarly journals Myosin XI-K is involved in root organogenesis, polar auxin transport, and cell division

2018 ◽  
Vol 69 (12) ◽  
pp. 2869-2881 ◽  
Author(s):  
Mohamad Abu-Abied ◽  
Eduard Belausov ◽  
Sapir Hagay ◽  
Valera Peremyslov ◽  
Valerian Dolja ◽  
...  
Keyword(s):  
Cell Division ◽  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Root Organogenesis ◽  
Myosin Xi

Aluminium toxicity targets PIN2 in Arabidopsis root apices: Effects on PIN2 endocytosis, vesicular recycling, and polar auxin transport

2008 ◽  
Vol 53 (16) ◽  
pp. 2480-2487 ◽  
Author(s):  
Hong Shen ◽  
NingYan Hou ◽  
Markus Schlicht ◽  
YingLang Wan ◽  
Stefano Mancuso ◽  
...  
Keyword(s):  
Auxin Transport ◽  
Aluminium Toxicity ◽  
Polar Auxin Transport ◽  
Arabidopsis Root ◽  
Root Apices

scholarly journals Cytokinin-Dependent Control of GH3 Group II Family Genes in the Arabidopsis Root

Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 94 ◽  
Author(s):  
Emanuela Pierdonati ◽  
Simon Josef Unterholzner ◽  
Elena Salvi ◽  
Noemi Svolacchia ◽  
Gaia Bertolotti ◽  
...  
Keyword(s):  
Lateral Root ◽  
Root Meristem ◽  
Positional Information ◽  
Cytokinin Activity ◽  
Arabidopsis Root ◽  
Meristematic Cells ◽  
Meristem Size ◽  
A Cell ◽  
Group Ii ◽  
Developmental Switch

Abstract: The Arabidopsis root is a dynamic system where the interaction between different plant hormones controls root meristem activity and, thus, organ growth. In the root, a characteristic graded distribution of the hormone auxin provides positional information, coordinating the proliferating and differentiating cell status. The hormone cytokinin shapes this gradient by positioning an auxin minimum in the last meristematic cells. This auxin minimum triggers a cell developmental switch necessary to start the differentiation program, thus, regulating the root meristem size. To position the auxin minimum, cytokinin promotes the expression of the IAA-amido synthase group II gene GH3.17, which conjugates auxin with amino acids, in the most external layer of the root, the lateral root cap tissue. Since additional GH3 genes are expressed in the root, we questioned whether cytokinin to position the auxin minimum also operates via different GH3 genes. Here, we show that cytokinin regulates meristem size by activating the expression of GH3.5 and GH3.6 genes, in addition to GH3.17. Thus, cytokinin activity provides a robust control of auxin activity in the entire organ necessary to regulate root growth.

scholarly journals Endogenous oscillations of electric potential difference in the cambial region of the pine stem. II. Possible involvement of the oscillations in xylogenesis

2014 ◽  
Vol 61 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Wojciech Kurek
Keyword(s):  
Electric Potential ◽  
Auxin Transport ◽  
Cambial Activity ◽  
Polar Auxin Transport ◽  
Potential Difference ◽  
Wood Production ◽  
Polar Transport ◽  
Tissue Block ◽  
Late Wood ◽  
Electric Potential Difference

Direct and indirect interrelations between xylogenic processes and the endogenous electric potential difference (PD) oscillations generated in the cambial region of isolated tissue blocks from pine trunks were investigated. The frequency of transient PD changes varied during the season and displayed three minima which were concurrent with periods of initiation and termination of cambial activity and with the time of transition from early- to late-wood production. The oscillations were damped by TIBA - an inhibitor of polar auxin transport and stimulated by IAA, but only when the hormone was supplied to the apical end of the tissue block. This suggests that the polar transport of auxin may be involved in generation of the transient PD changes. Results of 2-channel recordings in one tissue block suggest that a part of the recorded oscillations (10-25 %) exhibit coordination in space and time: a wave-like pattern along the trunk axis is created by PD changes. The pattern might be a physical carrier of information coordinating processes of growth and differentiation in distant parts of the tree.

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