scholarly journals Molecular machinery of auxin synthesis, secretion, and perception in the unicellular chlorophyte alga Chlorella sorokiniana UTEX 1230

2017 ◽  
Author(s):  
Maya Khasin ◽  
Rebecca R. Cahoon ◽  
Kenneth W. Nickerson ◽  
Wayne R. Riekhof
Keyword(s):  
Acetic Acid ◽  
Auxin Transport ◽  
Higher Plants ◽  
Chlorella Sorokiniana ◽  
Auxin Signaling ◽  
Seed Plants ◽  
Auxin Receptor ◽  
Auxin Binding ◽  
Auxin Synthesis ◽  
Indole 3 Acetic Acid

AbstractIndole-3-acetic acid is a ubiquitous small molecule found in all domains of life. It is the predominant and most active auxin in seed plants, where it coordinates a variety of complex growth and development processes. The potential origin of auxin signaling in algae remains a matter of some controversy. In order to clarify the evolutionary context of algal auxin signaling, we undertook a genomic survey to assess whether auxin acts as a signaling molecule in the emerging model chlorophyte Chlorella sorokiniana UTEX 1230. C. sorokiniana produces the auxin indole-3-acetic acid (IAA), which was present in both the cell pellet and in the supernatant at a concentration of ~ 1 nM, and its genome encodes orthologs of genes related to auxin synthesis, transport, and signaling in higher plants. Candidate orthologs for the canonical AUX/IAA signaling pathway were not found; however, auxin-binding protein 1 (ABP1), an alternate auxin receptor, is present and highly conserved at essential auxin binding and zinc coordinating residues. Additionally, candidate orthologs for PIN proteins, responsible for intercellular, vectorial auxin transport in higher plants, were not found, but PILs (PIN-Like) proteins, a recently discovered family that mediates intracellular auxin transport, were identified. The distribution of auxin related gene in this unicellular chlorophyte demonstrates that a core suite of auxin signaling components was present early in the evolution of plants. Understanding the simplified auxin signaling pathways in chlorophytes will aid in understanding phytohormone signaling and crosstalk in seed plants, and in understanding the diversification and integration of developmental signals during the evolution of multicellular plants.

scholarly journals Transcriptome-wide analysis of auxin-induced carotenoid accumulation in Chlorella microalgae

2018 ◽  
Author(s):  
Faisal Alsenani ◽  
Taylor J. Wass ◽  
Ruijuan Ma ◽  
Eladl Eltanahy ◽  
Michael E. Netzel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
De Novo ◽  
Higher Plants ◽  
Abiotic Stress Tolerance ◽  
Auxin Signaling ◽  
Rna Seq ◽  
Carotenoid Accumulation ◽  
Close Relationship ◽  
Indole 3 Acetic Acid

AbstractMicroalgae are a commercially viable route for the production of carotenoids, including β-carotene and astaxanthin. In the current study, the commercially relevant microalga, Chlorella sp. BR2 was treated with four plant hormones: indole-3-acetic acid, salicylic acid, abscisic acid and methyl jasmonate, over a range of dosages and screened for enhanced carotenoid production. Indole-3-acetic acid was the only hormone with an inductive effect on carotenoid accumulation. As such, the transcriptome under the condition with the highest carotenoid increase was profiled using RNA-Seq and expressed sequences reconstructed with de novo assembly. This allowed for the profiling of transcriptome-wide changes following auxin treatment, revealing the active pathway components of auxininduced carotenogenesis. Data analysis specified the differentially expressed genes involved in auxin biosynthesis and signal transduction, which suggest a close relationship to equivalent pathways in higher plants. However unlike in plants, the ancient ABP1/SCFSKP2A/IBR5-mediated pathways for auxin response likely acted as the primary signaling route in Chlorella. As carotenoids are precursors for abscisic acid, the findings suggest a causative link between auxin signaling and abiotic stress tolerance.HighlightTranscriptomics of plant hormone-treated Chlorella revealed the active pathway components of auxin-induced carotenogenesis and included the ancient ABP1/SCFSKP2A/IBR5-mediated pathways. The manuscript presents the first documented transcriptomic data of auxin-treated microalgae.

An Auxin Binding Protein is Localized in the Symbiosome Membrane of Soybean Nodules

1993 ◽  
Vol 48 (1-2) ◽  
pp. 35-40 ◽  
Author(s):  
Andreas Jacobi ◽  
Rolf Zettl ◽  
Klaus Palme ◽  
Dietrich Werner
Keyword(s):  
Acetic Acid ◽  
Auxin Transport ◽  
Binding Protein ◽  
Naphthaleneacetic Acid ◽  
Dependent Manner ◽  
Symbiosome Membrane ◽  
Auxin Binding ◽  
Auxin Binding Protein ◽  
Triton X ◽  
Indole 3 Acetic Acid

Binding of tritiated indole-3-acetic acid ([3H]IAA) to symbiosome membranes of soybean nodules occurred in a protein-dependent manner and was competitively inhibited by unlabeled indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (1-NAA) and dithiothreitol (DTT), but not by tryptophan and benzoic acid. The symbiosome membranes bound IAA with a KD of 1 × 10-6 m. Photoaffinity labeling identified an auxin-binding protein (ABP) in the symbiosome membrane with an apparent molecular mass of 23 kDa. This 23 kDa protein was labeled either with 5-azido-[7-3H]indole-3-acetic acid ([3H]N3IAA) or with 5′-azido-[3,6-3H2]-1-naphthylphthalamic acid ([3H2]N3NPA). Labeling of the 23 kDa protein with [3H]N3IAA was competitively inhibited by unlabeled IAA and 1-NAA. NPA and quercetin, inhibitors of polar auxin transport, as well as rutin, a glycosylated derivative of quercetin, competed with IAA for binding. Conversely, [3H2]N3NPA labeling was inhibited by unlabeled IAA and NPA. The 23 kDa symbiosome membrane protein was partially solubilized with Triton X-100 and nearly completely using Triton X-114. The observation that auxin transport inhibitors compete with IAA for binding suggests that the symbiosome membrane ABP could be part of an auxin efflux carrier system required to control the auxin concentration in infected soybean nodule cells.

scholarly journals Changes in endogenous levels of IAA and PAA in rice seed during development, prediction of auxin signaling proteins and docking for its binding efficiency with auxin molecules

1970 ◽  
Vol 29 (3) ◽  
pp. 325-337
Author(s):  
V.M. Jhala ◽  
K.S. Chudasama ◽  
K.S. Chudasama ◽  
V.S. Thaker
Keyword(s):  
Acetic Acid ◽  
Higher Plants ◽  
Rice Genome ◽  
Auxin Signaling ◽  
Signaling Proteins ◽  
Rice Seed ◽  
Genome Data ◽  
Sink Size ◽  
Rice Seeds ◽  
Indole 3 Acetic Acid

Indole-3-acetic acid (IAA) and phenyl acetic acid (PAA) are two major physiologically active auxins, found in higher plants. The objective of this study was to evaluate changes in the endogenous levels of IAA and PAA in rice (Oryza sativa) seed and predict probable transporter and efflux (signaling) proteins for docking with auxins from the available rice genome data. IAA and PAA were estimated during rice seed development using sensitive and specific antibodies against each hormone. The levels of IAA and PAA were higher when sink size development was at its peak, suggesting an important role played by the auxin in sink size development of rice seed. Furthermore, auxin binding transporters proteins of rice were confirmed for docking purpose and compared with Arabidopsis and maize proteins. In this context, PAA docked with known IAA proteins; although, docking score of IAA was higher than that of PAA in rice seed. Twelve genes of the auxin efflux carrier (PIN family) of rice were also analysed for phylogeny relatedness with Arabidopsis and maize, to further understanding auxin concentrations and efflux within rice seeds. The predicted PIN proteins for IAA efflux of rice showed docking affinities with PAA, revealed its role in maintaining physiological concentrations of auxins in rice seeds.

scholarly journals Differential effects of N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on auxin control of swelling of the shoots of Bryophyllum calycinum Salisb.

2017 ◽  
Vol 70 (3) ◽  
Author(s):  
Marian Saniewski ◽  
Justyna Góraj-Koniarska ◽  
Eleonora Gabryszewska ◽  
Kensuke Miyamoto ◽  
Junichi Ueda
Keyword(s):  
Acetic Acid ◽  
Differential Effect ◽  
Auxin Transport ◽  
Differential Mode ◽  
Treatment Area ◽  
Simultaneous Application ◽  
Triiodobenzoic Acid ◽  
Intact Plants ◽  
Naphthylphthalamic Acid ◽  
Indole 3 Acetic Acid

The effects of <em>N</em>-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on the swelling of the stem in intact and decapitated plants of <em>Bryophyllum calycinum</em> in relation to the interaction with auxin, indole-3-acetic acid (IAA), are described. NPA induced conspicuous local internode swelling only in the area of its application in intact plants and in the decapitated internode in the case of simultaneous application of IAA on the top of the internode. By contrast, TIBA applied to an internode of intact plants induced swelling along the entire internode above the treatment area, and similar results were obtained in the decapitated internode when TIBA was applied in the middle of the internode and IAA was applied onto the top of the internode. The differential effect of NPA and TIBA on stem swelling in <em>B. calycinum</em> is discussed in relation to their differential mode of action on auxin transport.

scholarly journals Quorum Sensing and Indole-3-Acetic Acid Degradation Play a Role in Colonization and Plant Growth Promotion of Arabidopsis thaliana by Burkholderia phytofirmans PsJN

2013 ◽  
Vol 26 (5) ◽  
pp. 546-553 ◽  
Author(s):  
Ana Zúñiga ◽  
María Josefina Poupin ◽  
Raúl Donoso ◽  
Thomas Ledger ◽  
Nicolás Guiliani ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Quorum Sensing ◽  
Plant Growth ◽  
Growth Promotion ◽  
Auxin Signaling ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid ◽  
Burkholderia Phytofirmans Psjn

Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant–bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.

The Route, Control and Compartmentation of Auxin Synthesis

1993 ◽  
Vol 20 (5) ◽  
pp. 527 ◽  
Author(s):  
HM Nonhebel ◽  
TP Cooney ◽  
R Simpson
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Recent Work ◽  
Aspartate Aminotransferase ◽  
Acid Synthesis ◽  
Pea Seedlings ◽  
Auxin Synthesis ◽  
Aromatic Aminotransferase ◽  
Work Supports ◽  
Indole 3 Acetic Acid

The study of indole-3-acetic acid synthesis has undergone something of a revival recently in an attempt to understand the control of IAA levels. Results are, however, contradictory with three separate hypotheses emerging. Our own work supports older evidence for L-tryptophan as the IAA precursor and appears to simplify the metabolism of tryptophan to IAA. Work comparing incorporation of 2H from 2H2O into IAA, tryptophan, tryptamine and indole-3-pyruvate in tomato shoots showed that the indole-3-pyruvate became labelled at a rate compatible with it being the sole intermediate between tryptophan and indole-3-acetaldehyde. Results also showed that tryptamine was not involved in IAA synthesis although it was present. Indole-3-acetaldoxime was not detected in tomato shoots. An aromatic aminotransferase able to catalyse the synthesis of indole-3-pyruvate has been purified from mung beans. This enzyme was separated from aspartate aminotransferase and is fairly specific for aromatic L-amino acids. Other work, however, has implicated D-tryptophan as a more direct precursor than the L-enantiomer. A D-tryptophan aminotransferase has been isolated from dark grown pea seedlings. Finally, other recent work has indicated the existence of an alternative biosynthetic route to IAA which does not involve tryptophan. These results are reviewed in this paper and the apparent contradictions between them discussed.

scholarly journals Control of vein-forming, striped gene expression by auxin signaling

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Anmol Krishna ◽  
Jason Gardiner ◽  
Tyler J. Donner ◽  
Enrico Scarpella
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Target Gene ◽  
Target Genes ◽  
Auxin Signaling ◽  
Plant Leaves ◽  
Vein Formation ◽  
Indole 3 Acetic Acid ◽  
Differential Affinity

Abstract Background Activation of gene expression in striped domains is a key building block of biological patterning, from the recursive formation of veins in plant leaves to that of ribs and vertebrae in our bodies. In animals, gene expression is activated in striped domains by the differential affinity of broadly expressed transcription factors for their target genes and the combinatorial interaction between such target genes. In plants, how gene expression is activated in striped domains is instead unknown. We address this question for the broadly expressed MONOPTEROS (MP) transcription factor and its target gene ARABIDOPSIS THALIANA HOMEOBOX FACTOR8 (ATHB8). Results We find that ATHB8 promotes vein formation and that such vein-forming function depends on both levels of ATHB8 expression and width of ATHB8 expression domains. We further find that ATHB8 expression is activated in striped domains by a combination of (1) activation of ATHB8 expression through binding of peak levels of MP to a low-affinity MP-binding site in the ATHB8 promoter and (2) repression of ATHB8 expression by MP target genes of the AUXIN/INDOLE-3-ACETIC-ACID-INDUCIBLE family. Conclusions Our findings suggest that a common regulatory logic controls activation of gene expression in striped domains in both plants and animals despite the independent evolution of their multicellularity.

scholarly journals Control of Vein-Forming, Striped Gene-Expression by Auxin Signaling

2020 ◽  
Author(s):  
Anmol Krishna ◽  
Jason Gardiner ◽  
Tyler J. Donner ◽  
Enrico Scarpella
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Target Gene ◽  
Target Genes ◽  
Auxin Signaling ◽  
Plant Leaves ◽  
Vein Formation ◽  
Indole 3 Acetic Acid ◽  
Differential Affinity

ABSTRACTActivation of gene expression in striped domains is a key building block of biological patterning, from the recursive formation of veins in plant leaves to that of ribs and vertebrae in our bodies. In animals, gene expression is activated in striped domains by the differential affinity of broadly expressed transcription factors for their target genes and the combinatorial interaction between such target genes. In plants, how gene expression is activated in striped domains is instead unknown. We address this question for the broadly expressed MONOPTEROS (MP) transcription factor and its target gene ARABIDOPSIS THALIANA HOMEOBOX FACTOR8 (ATHB8). We find that ATHB8 promotes vein formation and that such vein-forming function depends on both levels of ATHB8 expression and width of ATHB8 expression domains. We further find that ATHB8 expression is activated in striped domains by a combination of (1) activation of ATHB8 expression through binding of peak levels of MP to a low-affinity MP-binding site in the ATHB8 promoter and (2) repression of ATHB8 expression by MP target genes of the INDOLE-3-ACETIC-ACID-INDUCIBLE family such as BODENLOS. Our findings suggest that a common regulatory logic controls activation of gene expression in striped domains in both plants and animals despite the independent evolution of their multicellularity.

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