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Kiradjiev KB, Band LR. Multiscale Asymptotic Analysis Reveals How Cell Growth and Subcellular Compartments Affect Tissue-Scale Hormone Transport. Bull Math Biol 2023; 85:101. [PMID: 37702758 PMCID: PMC10499980 DOI: 10.1007/s11538-023-01199-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023]
Abstract
Determining how cell-scale processes lead to tissue-scale patterns is key to understanding how hormones and morphogens are distributed within biological tissues and control developmental processes. In this article, we use multiscale asymptotic analysis to derive a continuum approximation for hormone transport in a long file of cells to determine how subcellular compartments and cell growth and division affect tissue-scale hormone transport. Focusing our study on plant tissues, we begin by presenting a discrete multicellular ODE model tracking the hormone concentration in each cell's cytoplasm, subcellular vacuole, and surrounding apoplast, represented by separate compartments in the cell-file geometry. We allow the cells to grow at a rate that can depend both on space and time, accounting for both cytoplasmic and vacuolar expansion. Multiscale asymptotic analysis enables us to systematically derive the corresponding continuum model, obtaining an effective reaction-advection-diffusion equation and revealing how the effective diffusivity, effective advective velocity, and the effective sink term depend on the parameters in the cell-scale model. The continuum approximation reveals how subcellular compartments, such as vacuoles, can act as storage vessels, that significantly alter the effective properties of hormone transport, such as the effective diffusivity and the induced effective velocity. Furthermore, we show how cell growth and spatial variance across cell lengths affect the effective diffusivity and the induced effective velocity, and how these affect the tissue-scale hormone distribution. In particular, we find that cell growth naturally induces an effective velocity in the direction of growth, whereas spatial variance across cell lengths induces effective velocity due to the presence of an extra compartment, such as the apoplast and the vacuole, and variations in the relative sizes between the compartments across the file of cells. It is revealed that hormone transport is faster across cells of decreasing lengths than cells with increasing lengths. We also investigate the effect of cell division on transport dynamics, assuming that each cell divides as soon as it doubles in size, and find that increasing the time between successive cell divisions decreases the growth rate, which enhances the effect of cell division in slowing hormone transport. Motivated by recent experimental discoveries, we discuss particular applications for transport of gibberellic acid (GA), an important growth hormone, within the Arabidopsis root. The model reveals precisely how membrane proteins that mediate facilitated GA transport affect the effective tissue-scale transport. However, the results are general enough to be relevant to other plant hormones, or other substances that are transported in a similar way in any type of cells.
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Affiliation(s)
- K B Kiradjiev
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - L R Band
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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Solanki M, Shukla LI. Recent advances in auxin biosynthesis and homeostasis. 3 Biotech 2023; 13:290. [PMID: 37547917 PMCID: PMC10400529 DOI: 10.1007/s13205-023-03709-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 07/18/2023] [Indexed: 08/08/2023] Open
Abstract
The plant proliferation is linked with auxins which in turn play a pivotal role in the rate of growth. Also, auxin concentrations could provide insights into the age, stress, and events leading to flowering and fruiting in the sessile plant kingdom. The role in rejuvenation and plasticity is now evidenced. Interest in plant auxins spans many decades, information from different plant families for auxin concentrations, transcriptional, and epigenetic evidences for gene regulation is evaluated here, for getting an insight into pattern of auxin biosynthesis. This biosynthesis takes place via an tryptophan-independent and tryptophan-dependent pathway. The independent pathway initiated before the tryptophan (trp) production involves indole as the primary substrate. On the other hand, the trp-dependent IAA pathway passes through the indole pyruvic acid (IPyA), indole-3-acetaldoxime (IAOx), and indole acetamide (IAM) pathways. Investigations on trp-dependent pathways involved mutants, namely yucca (1-11), taa1, nit1, cyp79b and cyp79b2, vt2 and crd, and independent mutants of tryptophan, ins are compiled here. The auxin conjugates of the IAA amide and ester-linked mutant gh3, iar, ilr, ill, iamt1, ugt, and dao are remarkable and could facilitate the assimilation of auxins. Efforts are made herein to provide an up-to-date detailed information about biosynthesis leading to plant sustenance. The vast information about auxin biosynthesis and homeostasis is consolidated in this review with a simplified model of auxin biosynthesis with keys and clues for important missing links since auxins can enable the plants to proliferate and override the environmental influence and needs to be probed for applications in sustainable agriculture. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03709-6.
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Affiliation(s)
- Manish Solanki
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Kalapet, Pondicherry, 605014 India
- Puducherry, India
| | - Lata Israni Shukla
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Kalapet, Pondicherry, 605014 India
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Yuan P, Borrego E, Park YS, Gorman Z, Huang PC, Tolley J, Christensen SA, Blanford J, Kilaru A, Meeley R, Koiwa H, Vidal S, Huffaker A, Schmelz E, Kolomiets MV. 9,10-KODA, an α-ketol produced by the tonoplast-localized 9-lipoxygenase ZmLOX5, plays a signaling role in maize defense against insect herbivory. MOLECULAR PLANT 2023; 16:1283-1303. [PMID: 37434355 DOI: 10.1016/j.molp.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/10/2023] [Accepted: 07/07/2023] [Indexed: 07/13/2023]
Abstract
13-Lipoxygenases (LOXs) initiate the synthesis of jasmonic acid (JA), the best-understood oxylipin hormone in herbivory defense. However, the roles of 9-LOX-derived oxylipins in insect resistance remain unclear. Here, we report a novel anti-herbivory mechanism mediated by a tonoplast-localized 9-LOX, ZmLOX5, and its linolenic acid-derived product, 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (9,10-KODA). Transposon-insertional disruption of ZmLOX5 resulted in the loss of resistance to insect herbivory. lox5 knockout mutants displayed greatly reduced wound-induced accumulation of multiple oxylipins and defense metabolites, including benzoxazinoids, abscisic acid (ABA), and JA-isoleucine (JA-Ile). However, exogenous JA-Ile failed to rescue insect defense in lox5 mutants, while applications of 1 μM 9,10-KODA or the JA precursor, 12-oxo-phytodienoic acid (12-OPDA), restored wild-type resistance levels. Metabolite profiling revealed that exogenous 9,10-KODA primed the plants for increased production of ABA and 12-OPDA, but not JA-Ile. While none of the 9-oxylipins were able to rescue JA-Ile induction, the lox5 mutant accumulated lower wound-induced levels of Ca2+, suggesting this as a potential explanation for lower wound-induced JA. Seedlings pretreated with 9,10-KODA exhibited rapid or more robust wound-induced defense gene expression. In addition, an artificial diet supplemented with 9,10-KODA arrested fall armyworm larvae growth. Finally, analysis of single and double lox5 and lox10 mutants showed that ZmLOX5 also contributed to insect defense by modulating ZmLOX10-mediated green leaf volatile signaling. Collectively, our study uncovered a previously unknown anti-herbivore defense and hormone-like signaling activity for a major 9-oxylipin α-ketol.
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Affiliation(s)
- Peiguo Yuan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA
| | - Eli Borrego
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA; Currently at Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Yong-Soon Park
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA; Department of Plant Resources, Agriculture and Fisheries Life Science Research Institute, Kongju National University, Yesan, Chungnam 32439, South Korea
| | - Zachary Gorman
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA
| | - Pei-Cheng Huang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA
| | - Jordan Tolley
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Shawn A Christensen
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA; College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Jantana Blanford
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Aruna Kilaru
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37659, USA
| | - Robert Meeley
- Formerly at Corteva Agriscience, Johnston, IA 50131, USA
| | - Hisashi Koiwa
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Stefan Vidal
- Department of Crop Sciences, Agricultural Entomology, Georg-August-Universität, 37077 Göttingen, Germany
| | - Alisa Huffaker
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92037, USA
| | - Eric Schmelz
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92037, USA
| | - Michael V Kolomiets
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840-2132, USA.
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Živanović BD, Luković JD, Korać A, Stanić M, Spasić SZ, Galland P. Signal transduction in Phycomyces sporangiophores: columella as a novel sensory organelle mediating auxin-modulated growth rate and membrane potential. PROTOPLASMA 2022; 259:917-935. [PMID: 34595603 DOI: 10.1007/s00709-021-01709-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
The growing zone (GZ) of the unicellular coenocytic sporangiophore of Phycomyces blakesleeanus represents the site of stimulus reception (light, gravity, gas) and stimulus response, i.e., local modulations of the elongation growth, which may result, in dependence of the stimulus direction, in tropic bending. Until now, evidence for a possible participation of the columella in sensory reception is absent. We confirm with light microscopy earlier studies that show that the GZ and the columella are not separated by a membrane or cell wall, but rather form a spatial continuum that allows free exchange of cytoplasm and organelle transport. Evidence is presented that the columella is responsive to external stimuli. Columellae, from which spores and sporangial cell wall had been removed, respond to exogenous auxin with a local depolarization of the membrane potential and an increased growth rate of the GZ. In contrast, auxin applied to the GZ causes a decrease of the growth rate irrespective of the presence or absence of sporangia. The response pattern is specific and relevant for the sensory reception of Phycomyces, because the light-insensitive mutant C148carAmadC, which lacks the RAS-GAP protein MADC, displays abnormal IAA sensitivity and membrane depolarization. We argue that the traditional concept of the GZ as the only stimulus-sensitive zone should be abandoned in favor of a model in which GZ and columella operate as a single entity capable to orchestrate a multitude of stimulus inputs, including auxin, to modulate the membrane potential and elongation growth of the GZ.
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Affiliation(s)
- Branka D Živanović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS, 7001, Australia.
| | - Jelena Danilović Luković
- Institute for Application of Nuclear Energy, University of Belgrade, Banatska 31b, 11080, Belgrade-Zemun, Serbia
| | - Aleksandra Korać
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000, Belgrade, Serbia
| | - Marina Stanić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia
| | - Sladjana Z Spasić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia
- Singidunum University, Danijelova 32, Belgrade, Serbia
| | - Paul Galland
- Faculty of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, 35032, Marburg, Germany
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Agarwal P, Baraiya BM, Joshi PS, Patel M, Parida AK, Agarwal PK. AlRab7 from Aeluropus lagopoides ameliorates ion toxicity in transgenic tobacco by regulating hormone signaling and reactive oxygen species homeostasis. PHYSIOLOGIA PLANTARUM 2021; 173:1448-1462. [PMID: 33934375 DOI: 10.1111/ppl.13449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/16/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
The plants endomembrane system of the cellular compartments with its complex membrane trafficking network facilitates transport of macromolecules. The endomembrane dynamics are essential for maintaining basic and specific cellular functions including adaptation to the extracellular environment. The plant vacuole serves as a reservoir for nutrients and toxic metabolites and performs detoxification processes to maintain cellular homeostasis. The overexpression of AlRab7, a vesicle trafficking gene from Aeluropus lagopoides, improved germination and growth and reduced ionic and oxidative stress in transgenics. Moreover, the root and shoot of transgenic tobacco showed differential accumulation of phytohormone ABA and IAA with different ionic stresses. The improved growth (root and shoot length) can be co-related with higher IAA accumulation with NaCl stress. The low Na+ /K+ ratio with different NaCl stress treatments indicates better ion homeostasis in transgenics. Furthermore, the increased stomatal density and higher number of open stomata on both leaf surfaces in transgenics during NaCl stress suggest better gaseous exchange/functioning of guard cells. The maintained or increased superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase antioxidative enzyme activities suggest that an extensive reactive oxygen species (ROS) scavenging system was triggered to detoxify cellular ROS, which remained at low levels in transgenics during the different stress treatments. Our results suggest that the AlRab7 transgenic tobacco ameliorates ionic stress by facilitating differential and selective ion transport at vacuolar membrane regulating hormone signaling, ROS homeostasis, stomatal development, and movement.
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Affiliation(s)
- Parinita Agarwal
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
| | - Bhagirath M Baraiya
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Priyanka S Joshi
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Monika Patel
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Asish K Parida
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Pradeep K Agarwal
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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6
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Lee J, Kim H, Park SG, Hwang H, Yoo SI, Bae W, Kim E, Kim J, Lee HY, Heo TY, Kang KK, Lee Y, Hong CP, Cho H, Ryu H. Brassinosteroid-BZR1/2-WAT1 module determines the high level of auxin signalling in vascular cambium during wood formation. THE NEW PHYTOLOGIST 2021; 230:1503-1516. [PMID: 33570747 DOI: 10.1111/nph.17265] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
The tight regulation of local auxin homeostasis and signalling maxima in xylem precursor cells specifies the organising activity of the vascular cambium and consequently promotes xylem differentiation and wood formation. However, the molecular mechanisms underlying the local auxin signalling maxima in the vascular cambium are largely unknown. Here, we reveal that brassinosteroid (BR)-activated WALLS ARE THIN1 (WAT1) facilitates wood formation by enhancing local auxin signalling in the vascular cambium in Solanum lycopersicum. Growth defects and low auxin signalling readouts in the BR-deficient tomato cultivar, Micro-Tom, were associated with a novel recessive allele, Slwat1-copi, created by the insertion of a retrotransposon in the last exon of the SlWAT1 locus. Molecular and genetic studies by generating the gain-of-function and loss-of-function tomato mutants revealed that SlWAT1 is a critical regulator for fine tuning local auxin homeostasis and signalling outputs in vascular cambium to facilitate secondary growth. Finally, we discovered that BR-regulated SlBZR1/2 directly activated downstream auxin responses by SlWAT1 upregulation in xylem precursor cells to facilitate xylem differentiation and subsequent wood formation. Our data suggest that the BR-SlBZR1/2-WAT1 signalling network contributes to the high level of auxin signalling in the vascular cambium for secondary growth.
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Affiliation(s)
- Jinsu Lee
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | - Hyemin Kim
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
| | | | - Hyeona Hwang
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
| | | | - Wonsil Bae
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
| | - Eunhui Kim
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
| | - Jaehoon Kim
- Department of Information and Statistics, Chungbuk National University, Cheongju, 28644, Korea
| | - Hwa-Yong Lee
- Department of Forest Science, Chungbuk National University, Cheongju, 28644, Korea
| | - Tae-Young Heo
- Department of Information and Statistics, Chungbuk National University, Cheongju, 28644, Korea
| | - Kwon Kyoo Kang
- Department of Horticulture, Hankyong National University, Ansung, 17579, Korea
| | - Yuree Lee
- School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | | | - Hyunwoo Cho
- Department of Industrial Plant Science and Technology, Chungbuk National University, Cheongju, 28644, Korea
| | - Hojin Ryu
- Department of Biology, Chungbuk National University, Cheongju, 28644, Korea
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García-González J, Kebrlová Š, Semerák M, Lacek J, Kotannal Baby I, Petrášek J, Schwarzerová K. Arp2/3 Complex Is Required for Auxin-Driven Cell Expansion Through Regulation of Auxin Transporter Homeostasis. FRONTIERS IN PLANT SCIENCE 2020; 11:486. [PMID: 32425966 PMCID: PMC7212389 DOI: 10.3389/fpls.2020.00486] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 03/31/2020] [Indexed: 05/29/2023]
Abstract
The Arp2/3 complex is an actin nucleator shown to be required throughout plant morphogenesis, contributing to processes such as cell expansion, tissue differentiation or cell wall assembly. A recent publication demonstrated that plants lacking functional Arp2/3 complex also present defects in auxin distribution and transport. This work shows that Arp2/3 complex subunits are predominantly expressed in the provasculature, although other plant tissues also show promoter activity (e.g., cotyledons, apical meristems, or root tip). Moreover, auxin can trigger subunit expression, indicating a role of this phytohormone in mediating the complex activity. Further investigation of the functional interaction between Arp2/3 complex and auxin signaling also reveals their cooperation in determining pavement cell shape, presumably through the role of Arp2/3 complex in the correct auxin carrier trafficking. Young seedlings of arpc5 mutants show increased auxin-triggered proteasomal degradation of DII-VENUS and altered PIN3 distribution, with higher levels of the protein in the vacuole. Closer observation of vacuolar morphology revealed the presence of a more fragmented vacuolar compartment when Arp2/3 function is abolished, hinting a generalized role of Arp2/3 complex in endomembrane function and protein trafficking.
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Affiliation(s)
- Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Štépánka Kebrlová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Matěj Semerák
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Jozef Lacek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Innu Kotannal Baby
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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Burdach Z, Siemieniuk A, Trela Z, Kurtyka R, Karcz W. Role of auxin (IAA) in the regulation of slow vacuolar (SV) channels and the volume of red beet taproot vacuoles. BMC PLANT BIOLOGY 2018; 18:102. [PMID: 29866031 PMCID: PMC5987474 DOI: 10.1186/s12870-018-1321-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 05/24/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND Auxin (IAA) is a central player in plant cell growth. In contrast to the well-established function of the plasma membrane in plant cell expansion, little is known about the role of the vacuolar membrane (tonoplast) in this process. RESULTS It was found that under symmetrical 100 mM K+ and 100 μM cytoplasmic Ca2+ the macroscopic currents showed a typical slow activation and a strong outward rectification of the steady-state currents. The addition of IAA at a final concentration of 1 μM to the bath medium stimulated the SV currents, whereas at 0.1 and 10 μM slight inhibition of SV currents was observed. The time constant, τ, decreased in the presence of this hormone. When single channels were analyzed, an increase in their activity was recorded with IAA compared to the control. The single-channel recordings that were obtained in the presence of IAA showed that auxin increased the amplitude of the single-channel currents. Interestingly, the addition of IAA to the bath medium with the same composition as the one that was used in the patch-clamp experiments showed that auxin decreased the volume of the vacuoles. CONCLUSIONS It is suggested that the SV channels and the volume of red beet taproot vacuoles are modulated by auxin (IAA).
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Affiliation(s)
- Zbigniew Burdach
- Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland
| | - Agnieszka Siemieniuk
- Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland
| | - Zenon Trela
- Department of Physics and Biophysics, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland
| | - Renata Kurtyka
- Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland
| | - Waldemar Karcz
- Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland
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