A Role for Auxin in Triggering Lamina Outgrowth of Unifacial Leaves

Abstract A common morphological feature of typical angiosperms is the patterning of lateral organs along primary axes of asymmetry—a proximodistal, a mediolateral, and an adaxial–abaxial axis. Angiosperm leaves usually have distinct adaxial–abaxial identity, which is required for the development of a flat shape. By contrast, many unifacial leaves, consisting of only the abaxial side, show a flattened morphology. This implicates a unique mechanism that allows leaf flattening independent of adaxial–abaxial identity. In this study, we report a role for auxin in outgrowth of unifacial leaves. In two closely related unifacial-leaved species of Juncaceae, Juncus prismatocarpus with flattened leaves, and J. wallichianus with transversally radialized leaves, the auxin-responsive gene GLYCOSIDE HYDROLASE3 (GH3) displayed spatially different expression patterns within leaf primordia. Treatment of J. prismatocarpus seedlings with exogenous auxin or auxin transport inhibitors, which disturb endogenous auxin distribution, eliminated leaf flatness, resulting in a transversally radialized morphology. These treatments did not affect the radialized morphology of leaves of J. wallichianus. Moreover, elimination of leaf flatness by these treatments accompanied dysregulated expression of genetic factors needed to specify the leaf central-marginal polarity in J. prismatocarpus. The findings imply that lamina outgrowth of unifacial leaves relies on proper placement of auxin, which might induce initial leaf flattening and subsequently act to specify leaf polarity, promoting further flattening growth of leaves.

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

Agronomy ◽

10.3390/agronomy9080435 ◽

2019 ◽

Vol 9 (8) ◽

pp. 435 ◽

Cited By ~ 2

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.

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Faculty Opinions recommendation of Auxin transport inhibitors block PIN1 cycling and vesicle trafficking.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1003242.31111 ◽

2001 ◽

Author(s):

Philip Benfey

Keyword(s):

Auxin Transport ◽

Vesicle Trafficking ◽

Transport Inhibitors ◽

Auxin Transport Inhibitors

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Faculty Opinions recommendation of Auxin transport inhibitors impair vesicle motility and actin cytoskeleton dynamics in diverse eukaryotes.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1108908.566054 ◽

2008 ◽

Author(s):

David G Oppenheimer

Keyword(s):

Actin Cytoskeleton ◽

Auxin Transport ◽

Transport Inhibitors ◽

Auxin Transport Inhibitors ◽

Cytoskeleton Dynamics

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Bioinformatics Analysis of Allele Frequencies and Expression Patterns of ACE2, TMPRSS2 and FURIN in Different Populations and Susceptibility to SARS-CoV-2

Genes ◽

10.3390/genes12071041 ◽

2021 ◽

Vol 12 (7) ◽

pp. 1041

Author(s):

Mohammad Tarek ◽

Hana Abdelzaher ◽

Firas Kobeissy ◽

Hassan A. N. El-Fawal ◽

Mohammed M. Salama ◽

...

Keyword(s):

Immune Response ◽

Genetic Factors ◽

Bioinformatics Analysis ◽

Expression Patterns ◽

Spike Protein ◽

Target Cells ◽

Health Crisis ◽

Expression Levels ◽

Different Populations ◽

Shed Light

The virus responsible for the COVID-19 global health crisis, SARS-CoV-2, has been shown to utilize the ACE2 protein as an entry point to its target cells. The virus has been shown to rely on the actions of TMPRSS2 (a serine protease), as well as FURIN (a peptidase), for the critical priming of its spike protein. It has been postulated that variations in the sequence and expression of SARS-CoV-2’s receptor (ACE2) and the two priming proteases (TMPRSS2 and FURIN) may be critical in contributing to SARS-CoV-2 infectivity. This study aims to examine the different expression levels of FURIN in various tissues and age ranges in light of ACE2 and TMPRSS2 expression levels using the LungMAP database. Furthermore, we retrieved expression quantitative trait loci (eQTLs) of the three genes and their annotation. We analyzed the frequency of the retrieved variants in data from various populations and compared it to the Egyptian population. We highlight FURIN’s potential interplay with the immune response to SARS-CoV-2 and showcase a myriad of variants of the three genes that are differentially expressed across populations. Our findings provide insights into potential genetic factors that impact SARS-CoV-2 infectivity in different populations and shed light on the varying expression patterns of FURIN.

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An evolutionary and developmental approach toward understanding of growth variations of two closely related dwarfism of Galium verum

Biologia ◽

10.2478/s11756-014-0479-0 ◽

2014 ◽

Vol 69 (12) ◽

Cited By ~ 1

Author(s):

Keum Jeong ◽

Jae-Hong Pak ◽

Jeong Kim

Keyword(s):

Cell Proliferation ◽

Genetic Factors ◽

Expression Patterns ◽

Mrna Differential Display ◽

Growth Patterns ◽

The Other ◽

Differential Growth ◽

Developmental Approach ◽

Differential Display Method ◽

Low Activity

AbstractGalium L. is one of the largest and most widespread genus of Rubiaceae, consisting of more than 650 species worldwide. Galium verum var. asiaticum (G. verum a.) is a perennial herbaceous and widely distributed in in Korea peninsula. On the other hand, Galium verum var. asiaticum for. pusillum (G. verum a.p.) is endemic to Korea, inhabiting only on high land of Mt. Halla of Jeju. G. verum a.p. appears to be a dwarfism of G. verum a. We wondered what physiological, environmental, or genetic factors rendered those two taxa morphologically differentiated. We found that G. verum a.p. shows a low activity of the cell proliferation and was not associated with responsiveness contents of auxin and gibberellins. In order to search for genetic factors involved, we carried out an mRNA differential display method using the ACPs, and isolated several different expression genes between the two taxa. We chose one of those genes, which encoded RADIALIS-like proteins: GvaRADL1 from G. verum a. and GvapRADL1 from G. verum a.p. We discuss the relevancy of the genetic variations in regard to the differential expression patterns of those genes and the differential growth patterns of the two variants.

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Auxin methylation is required for differential growth inArabidopsis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1806565115 ◽

2018 ◽

Vol 115 (26) ◽

pp. 6864-6869 ◽

Cited By ~ 10

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.

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

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014104 ◽

2020 ◽

Vol 295 (37) ◽

pp. 13094-13105 ◽

Cited By ~ 3

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.

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