scholarly journals Maintenance of Embryonic Auxin Distribution for Apical-Basal Patterning by PIN-FORMED–Dependent Auxin Transport in Arabidopsis

2005 ◽  
Vol 17 (9) ◽  
pp. 2517-2526 ◽  
Author(s):  
Dolf Weijers ◽  
Michael Sauer ◽  
Olivier Meurette ◽  
Jiří Friml ◽  
Karin Ljung ◽  
...  
Keyword(s):  
Auxin Transport ◽  
Auxin Distribution

scholarly journals Auxin methylation is required for differential growth inArabidopsis

2018 ◽  
Vol 115 (26) ◽  
pp. 6864-6869 ◽  
Author(s):  
Mohamad Abbas ◽  
Jorge Hernández-García ◽  
Stephan Pollmann ◽  
Sophia L. Samodelov ◽  
Martina Kolb ◽  
...  
Keyword(s):  
Gene Expression ◽  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Asymmetric Distribution ◽  
Loss Of Function ◽  
Differential Growth ◽  
Specific Expression ◽  
Auxin Homeostasis ◽  
Auxin Distribution ◽  
Gene Expression Levels

Asymmetric auxin distribution is instrumental for the differential growth that causes organ bending on tropic stimuli and curvatures during plant development. Local differences in auxin concentrations are achieved mainly by polarized cellular distribution of PIN auxin transporters, but whether other mechanisms involving auxin homeostasis are also relevant for the formation of auxin gradients is not clear. Here we show that auxin methylation is required for asymmetric auxin distribution across the hypocotyl, particularly during its response to gravity. We found that loss-of-function mutants inArabidopsis IAA CARBOXYL METHYLTRANSFERASE1(IAMT1) prematurely unfold the apical hook, and that their hypocotyls are impaired in gravitropic reorientation. This defect is linked to an auxin-dependent increase inPINgene expression, leading to an increased polar auxin transport and lack of asymmetric distribution of PIN3 in theiamt1mutant. Gravitropic reorientation in theiamt1mutant could be restored with either endodermis-specific expression ofIAMT1or partial inhibition of polar auxin transport, which also results in normalPINgene expression levels. We propose that IAA methylation is necessary in gravity-sensing cells to restrict polar auxin transport within the range of auxin levels that allow for differential responses.

scholarly journals Auxin-transporting ABC transporters are defined by a conserved D/E-P motif regulated by a prolylisomerase

2020 ◽  
Vol 295 (37) ◽  
pp. 13094-13105 ◽  
Author(s):  
Pengchao Hao ◽  
Jian Xia ◽  
Jie Liu ◽  
Martin Di Donato ◽  
Konrad Pakula ◽  
...  
Keyword(s):  
Abc Transporters ◽  
Plant Hormone ◽  
Auxin Transport ◽  
Physical Interaction ◽  
Transport Activity ◽  
Nucleotide Binding Domain ◽  
Higher Plant ◽  
Ppiase Activity ◽  
Auxin Distribution ◽  
A Cell

The plant hormone auxin must be transported throughout plants in a cell-to-cell manner to affect its various physiological functions. ABCB transporters are critical for this polar auxin distribution, but the regulatory mechanisms controlling their function is not fully understood. The auxin transport activity of ABCB1 was suggested to be regulated by a physical interaction with FKBP42/Twisted Dwarf1 (TWD1), a peptidylprolyl cis-trans isomerase (PPIase), but all attempts to demonstrate such a PPIase activity by TWD1 have failed so far. By using a structure-based approach, we identified several surface-exposed proline residues in the nucleotide binding domain and linker of Arabidopsis ABCB1, mutations of which do not alter ABCB1 protein stability or location but do affect its transport activity. P1008 is part of a conserved signature D/E-P motif that seems to be specific for auxin-transporting ABCBs, which we now refer to as ATAs. Mutation of the acidic residue also abolishes auxin transport activity by ABCB1. All higher plant ABCBs for which auxin transport has been conclusively proven carry this conserved motif, underlining its predictive potential. Introduction of this D/E-P motif into malate importer, ABCB14, increases both its malate and its background auxin transport activity, suggesting that this motif has an impact on transport capacity. The D/E-P1008 motif is also important for ABCB1-TWD1 interactions and activation of ABCB1-mediated auxin transport by TWD1. In summary, our data imply a new function for TWD1 acting as a putative activator of ABCB-mediated auxin transport by cis-trans isomerization of peptidyl-prolyl bonds.

scholarly journals Ontogenetic Changes in Auxin Biosynthesis and Distribution Determine the Organogenic Activity of the Shoot Apical Meristem in pin1 Mutants

2019 ◽  
Vol 20 (1) ◽  
pp. 180 ◽  
Author(s):  
Alicja Banasiak ◽  
Magdalena Biedroń ◽  
Alicja Dolzblasz ◽  
Mateusz Adam Berezowski
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Auxin Transport ◽  
Vascular System ◽  
Auxin Biosynthesis ◽  
Wild Type ◽  
Ontogenetic Changes ◽  
Auxin Distribution ◽  
Stem Development ◽  
Knockout Mutation

In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) regulates two crucial developmental processes: organogenesis and vascular system formation. However, the knockout mutation in the PIN1 gene does not fully inhibit these two processes. Therefore, we investigated a potential source of auxin for organogenesis and vascularization during inflorescence stem development. We analyzed auxin distribution in wild-type (WT) and pin1 mutant plants using a refined protocol of auxin immunolocalization; auxin activity, with the response reporter pDR5:GFP; and expression of auxin biosynthesis genes YUC1 and YUC4. Our results revealed that regardless of the functionality of PIN1-mediated PAT, auxin is present in the SAM and vascular strands. In WT plants, auxin always accumulates in all cells of the SAM, whereas in pin1 mutants, its localization within the SAM changes ontogenetically and is related to changes in the structure of the vascular system, organogenic activity of SAM, and expression levels of YUC1 and YUC4 genes. Our findings indicate that the presence of auxin in the meristem of pin1 mutants is an outcome of at least two PIN1-independent mechanisms: acropetal auxin transport from differentiated tissues with the use of vascular strands and auxin biosynthesis within the SAM.

scholarly journals Identification and Expression Analysis of the PIN and AUX/LAX Gene Families in Ramie (Boehmeria nivea L. Gaud)

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 435 ◽  
Author(s):  
Yaning Bao ◽  
Xing Huang ◽  
Muzammal Rehman ◽  
Yunhe Wang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Auxin Transport ◽  
Expression Patterns ◽  
Gene Families ◽  
Ramie Fiber ◽  
Biological Functions ◽  
Qrt Pcr ◽  
Boehmeria Nivea ◽  
Auxin Distribution ◽  
Indole 3 Acetic Acid

Auxin regulates diverse aspects of growth and development. Furthermore, polar auxin transport, which is mediated by the PIN-FORMED (PIN) and AUXIN1/LIKE-AUX (AUX/LAX) proteins, plays a crucial role in auxin distribution. In this study, six PIN and four AUX/LAX genes were identified in ramie (Boehmeria nivea L.). We used qRT-PCR to characterize and analyze the two gene families, including phylogenetic relationships, intron/exon structures, cis-elements, subcellular localization, and the expression patterns in different tissues. The expression of these genes in response to indole-3-acetic acid (IAA) treatment and drought stress was also assessed; the results indicate that most of the BnAUX/LAX and BnPIN genes were regulated as a result of IAA treatment and drought stress. Our study provides insights into ramie auxin transporters and lays the foundation for further analysis of their biological functions in ramie fiber development and adaptation to environmental stresses.

scholarly journals Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice

2015 ◽  
Vol 112 (35) ◽  
pp. 11102-11107 ◽  
Author(s):  
Linchuan Liu ◽  
Hongning Tong ◽  
Yunhua Xiao ◽  
Ronghui Che ◽  
Fan Xu ◽  
...  
Keyword(s):  
Grain Size ◽  
Auxin Transport ◽  
Vascular Tissue ◽  
Plant Biomass ◽  
Key Factors ◽  
Auxin Distribution ◽  
New Strategy ◽  
Dna Insertion ◽  
Auxin Transport Inhibitor ◽  
Naphthylphthalamic Acid

Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity.

scholarly journals Antagonistic and auxin-dependent phosphoregulation of columella PIN proteins controls lateral root gravitropic setpoint angle in Arabidopsis

2019 ◽  
Author(s):  
Suruchi Roychoudhry ◽  
Katelyn Sageman-Furnas ◽  
Chris Wolverton ◽  
Heather L. Goodman ◽  
Peter Grones ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Lateral Root ◽  
Auxin Transport ◽  
Lateral Roots ◽  
Gravity Vector ◽  
Independent Manner ◽  
Gravitropic Response ◽  
Auxin Distribution ◽  
Columella Cells ◽  
Molecular Framework

AbstractLateral roots of many species are maintained at non-vertical angles with respect to gravity. These gravitropic setpoint angles (GSAs) are intriguing because their maintenance requires that roots are able to effect gravitropic response both with and against the gravity vector. Here we have used the Arabidopsis lateral root in order to investigate the molecular basis of the maintenance of non-vertical GSAs. We show that gravitropism in the lateral root is angle-dependent and that both upward and downward graviresponse requires auxin transport and the generation of auxin asymmetries consistent with the Cholodny-Went model. We show that the symmetry in auxin distribution in lateral roots growing at GSA can be traced back to a net, balanced polarization of PIN3 and PIN7 auxin transporters in the columella cells. Further, upward and downward graviresponse in lateral roots correlates with corresponding changes in PIN3 and PIN7 polar localisation. Finally, we show that auxin, in addition to driving tropic growth in the lateral root, acts within the columella to regulate GSA via the PIN phosphatase subunit RCN1 in a PIN3-dependent and PIN7-independent manner. Together, these findings provide a molecular framework for understanding gravity-dependent nonvertical growth in Arabidopsis lateral roots.

MATHEMATICAL MODELING OF AUXIN TRANSPORT IN PROTOXYLEM AND PROTOPHLOEM OF ARABIDOPSIS THALIANA ROOT TIPS

2013 ◽  
Vol 11 (01) ◽  
pp. 1340010 ◽  
Author(s):  
EKATERINA S. NOVOSELOVA ◽  
VICTORIA V. MIRONOVA ◽  
NADYA A. OMELYANCHUK ◽  
FEDOR V. KAZANTSEV ◽  
VITALY A. LIKHOSHVAI
Keyword(s):  
Arabidopsis Thaliana ◽  
Active Transport ◽  
Auxin Transport ◽  
Positional Information ◽  
Root Tip ◽  
Root Tips ◽  
Auxin Distribution ◽  
A Cell ◽  
Optimal Values ◽  
Main Regulator

Phytohormone auxin is the main regulator of plant growth and development. Nonuniform auxin distribution in plant tissue sets positional information, which determines morphogenesis. Auxin is transported in tissue by means of diffusion and active transport through the cell membrane. There is a number of auxin carriers performing its influx into a cell (AUX\LAX family) or efflux from a cell (PIN, PGP families). The paper presents mathematical models for auxin transport in vascular tissues of Arabidopsis thaliana L.root tip, namely protophloem and protoxylem. Tissue specificity of auxin active transport was considered in these models. There is PIN-mediated auxin efflux in both protoxylem and protophloem, but AUX1-mediated influx exists only in protophloem. Optimal values of parameters were adjusted for model solutions to fit the experimentally observed auxin distributions in the root tip. Based on simulation results we predicted that shoot-derived auxin flow to protophloem is lower than one to protoxylem, and the efficiency of PIN-mediated auxin transport in protophloem is higher than in protoxylem. In summary, our simulation showed that despite the same auxin distribution pattern, provascular tissues in the root tip differ in dynamics of auxin transport.

scholarly journals Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Melina Zourelidou ◽  
Birgit Absmanner ◽  
Benjamin Weller ◽  
Inês CR Barbosa ◽  
Björn C Willige ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Vascular Plants ◽  
Auxin Transport ◽  
Efflux Transporters ◽  
Cell Distribution ◽  
Auxin Distribution ◽  
Crucial Component ◽  
Inflorescence Stems ◽  
Transport Control

The development and morphology of vascular plants is critically determined by synthesis and proper distribution of the phytohormone auxin. The directed cell-to-cell distribution of auxin is achieved through a system of auxin influx and efflux transporters. PIN-FORMED (PIN) proteins are proposed auxin efflux transporters, and auxin fluxes can seemingly be predicted based on the—in many cells—asymmetric plasma membrane distribution of PINs. Here, we show in a heterologous Xenopus oocyte system as well as in Arabidopsis thaliana inflorescence stems that PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family. At the same time, we reveal that D6PKs and PID have differential phosphosite preferences. Our study suggests that PIN activation by protein kinases is a crucial component of auxin transport control that must be taken into account to understand auxin distribution within the plant.

scholarly journals The AtCRK5 Protein Kinase Is Required to Maintain the ROS NO Balance Affecting the PIN2-Mediated Root Gravitropic Response in Arabidopsis

2021 ◽  
Vol 22 (11) ◽  
pp. 5979
Author(s):  
Ágnes Cséplő ◽  
Laura Zsigmond ◽  
Norbert Andrási ◽  
Abu Imran Baba ◽  
Nitin M. Labhane ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Auxin Transport ◽  
Root Tip ◽  
Wild Type ◽  
Root Tips ◽  
H2o2 Treatment ◽  
Gravitropic Response ◽  
Auxin Distribution ◽  
Regulatory Loop ◽  
Oxidative Stress Inducer

The Arabidopsis AtCRK5 protein kinase is involved in the establishment of the proper auxin gradient in many developmental processes. Among others, the Atcrk5-1 mutant was reported to exhibit a delayed gravitropic response via compromised PIN2-mediated auxin transport at the root tip. Here, we report that this phenotype correlates with lower superoxide anion (O2•−) and hydrogen peroxide (H2O2) levels but a higher nitric oxide (NO) content in the mutant root tips in comparison to the wild type (AtCol-0). The oxidative stress inducer paraquat (PQ) triggering formation of O2•− (and consequently, H2O2) was able to rescue the gravitropic response of Atcrk5-1 roots. The direct application of H2O2 had the same effect. Under gravistimulation, correct auxin distribution was restored (at least partially) by PQ or H2O2 treatment in the mutant root tips. In agreement, the redistribution of the PIN2 auxin efflux carrier was similar in the gravistimulated PQ-treated mutant and untreated wild type roots. It was also found that PQ-treatment decreased the endogenous NO level at the root tip to normal levels. Furthermore, the mutant phenotype could be reverted by direct manipulation of the endogenous NO level using an NO scavenger (cPTIO). The potential involvement of AtCRK5 protein kinase in the control of auxin-ROS-NO-PIN2-auxin regulatory loop is discussed.

scholarly journals Auxin-induced developmental patterns in Brassica juncea embryos

Development ◽  
1998 ◽  
Vol 125 (5) ◽  
pp. 879-887 ◽  
Author(s):  
K. Hadfi ◽  
V. Speth ◽  
G. Neuhaus
Keyword(s):  
Brassica Juncea ◽  
Auxin Transport ◽  
Developmental Patterns ◽  
Globular Embryos ◽  
Auxin Distribution ◽  
Wide Range ◽  
Auxin Transport Inhibitor ◽  
Indole 3 Acetic Acid ◽  
Chlorophenoxyisobutyric Acid

To investigate the mechanism of auxin action during pattern formation in dicot embryos, we tested the effects of the natural auxin indole-3-acetic acid (IAA), the auxin transport inhibitor N-(1-naphthyl)thalamic acid (NPA) and the antiauxin p-chlorophenoxyisobutyric acid (PCIB). In vitro treatments of isolated zygotic Brassica juncea embryos with these substances led to a wide range of morphogenetic alterations. Treatment of globular embryos with exogenous auxin (10-40 microM) either completely inhibited morphogenesis, resulting in ball-shaped embryos, or caused the development of egg- and cucumber-shaped embryos, which only consisted of a shortened hypocotyl without any apical structures. Axis duplication was observed sometimes after inhibition of auxin transport in globular embryos, and led to the development of twin embryos. During the transition from globular to heart stage, changes in auxin distribution or activity frequently caused the development of either split-collar or collar-cotyledons. Antiauxin inhibited cotyledon growth, leading to embryos with single or no cotyledons, or inhibited the development of the hypocotyl and the radicle. Inhibition of auxin transport in transition embryos sometimes led to axis broadening, which resulted in the development of two radicles. The described changes in embryo shapes represent arrests in different auxin-regulated developmental steps and phenocopy some Arabidopsis morphogenetic mutants.

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