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Raven JA. Avoiding and allowing apatite precipitation in oxygenic photolithotrophs. THE NEW PHYTOLOGIST 2023; 238:1801-1812. [PMID: 36856343 DOI: 10.1111/nph.18849] [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: 12/06/2022] [Accepted: 02/24/2023] [Indexed: 05/04/2023]
Abstract
The essential elements Ca and P, taken up and used metabolically as Ca2+ and H2 PO4 - /HPO4 2- respectively, could precipitate as one or more of the insoluble forms calcium phosphate (mainly apatite) if the free ion concentrations and pH are high enough. In the cytosol, chloroplast stroma, and mitochondrial matrix, the very low free Ca2+ concentration avoids calcium phosphate precipitation, apart from occasionally in the mitochondrial matrix. The low free Ca2+ concentration in these compartments is commonly thought of in terms of the role of Ca2+ in signalling. However, it also helps avoids calcium phosphate precipitation, and this could be its earliest function in evolution. In vacuoles, cell walls, and xylem conduits, there can be relatively high concentrations of Ca2+ and inorganic orthophosphate, but pH and/or other ligands for Ca2+ , suggests that calcium phosphate precipitates are rare. However, apatite is precipitated under metabolic control in shoot trichomes, and by evaporative water loss in hydathodes, in some terrestrial flowering plants. In aquatic macrophytes that deposit CaCO3 on their cell walls or in their environment as a result of pH increase or removal of inhibitors of nucleation or crystal growth, phosphate is sometimes incorporated in the CaCO3 . Calcium phosphate precipitation also occurs in some stromatolites.
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Affiliation(s)
- John A Raven
- Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Climate Change Cluster, Faculty of Science, University of Technology, Sydney, Ultimo, NSW, 2007, Australia
- School of Biological Sciences, University of Western Australia, Crawley, WA, 6009, Australia
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Vafadar F, Ehsanzadeh P. Synergistic effects of calcium and melatonin on physiological and phytochemical attributes of Dracocephalum kotschyi genotypes under salinity stress. PHYSIOLOGIA PLANTARUM 2023; 175:e13912. [PMID: 37041729 DOI: 10.1111/ppl.13912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 06/19/2023]
Abstract
Since regulatory roles of calcium (Ca) and melatonin (MT) in physiological responses of plants to salinity stress are lacking, various Dracocephalum kotschyi genotypes (Bojnord, Urmia, Fereydunshahr, and Semirom) were pretreated with exogenous Ca (5 mM), MT (100 μM), and Ca + MT in the presence of salt (75 mM NaCl). In addition measuring the concentration of phenolic compounds by high performance liquid chromatography (HPLC), histochemical evaluations of essential oils and phenolic compounds in glandular trichomes of leaf samples were performed by light microscope. Salt stress reduced shoot fresh (SFW) and dry weight (SDW), leaf area (LA), relative water content (RWC), and maximum efficiency of photosystem II (Fv /Fm ), but enhanced total phenolic content (TPC) and total flavonoids content (TFC), phenolic compounds concentrations, DPPH radical scavenging capacity, electrolyte leakage (EL), proline and hydrogen peroxide (H2 O2 ) concentrations, and Na+ /K+ and essential oils and TPC of the glandular trichomes of leaves in all D. kotschyi genotypes. Foliar spraying of Ca, MT, and particularly Ca + MT on D. kotschyi seedlings improved SFW, SDW, RWC, TPC, TFC, proline and phenolic compounds concentrations, Fv /Fm , and DPPH radical scavenging capacity, but reduced H2 O2 , EL, and Na+ /K+ in the leaves and essential oils and TPC in the glandular trichomes of all genotypes under both non-stress and salt stress conditions. These findings indicate that the crosstalk between MT and Ca synergistically improves salt tolerance, TPC and TFC, phenolic compounds concentration, and essential oils accumulation in glandular trichomes of different D. kotschyi genotypes.
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Affiliation(s)
- Farinaz Vafadar
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
| | - Parviz Ehsanzadeh
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
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Seo D, Park J, Kim KW. Appressed, directed and silicified trichomes of the kudzu climbing vine. Microscopy (Oxf) 2022; 71:341-346. [PMID: 35916452 DOI: 10.1093/jmicro/dfac038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/12/2022] [Accepted: 08/02/2022] [Indexed: 12/13/2022] Open
Abstract
Kudzu (Pueraria montana var. lobata) is becoming one of the most prevalent climbing vines in urban forests. Here, surface characteristics of kudzu leaves and stems are investigated using field-emission scanning electron microscopy and X-ray microanalysis. The leaf and stem surfaces were characterized by different types of trichomes. No adhesive pads, modified hooks or tendrils were found on kudzu vines. Trichomes on the leaves and stems of kudzu could be categorized into (i) complex bulbous glandular trichomes and (ii) needle-shaped nonglandular trichomes (NSNGTs). Two morphotypes of the nonglandular trichomes were present on the stems: (i) long hairy nonglandular trichomes and (ii) short NSNGTs. The leaf trichomes were appressed and oriented in an uphill direction, whereas the stem trichomes were appressed and oriented in a downhill direction. This opposite trichome orientation appears to facilitate climbing and prohibits slipping of kudzu vines through differential friction between the plants and the kudzu vines. X-ray microanalysis revealed a distinct accumulation of silicon in the leaf and stem trichomes. These results suggest that appressed, directed and silicified trichomes may contribute to the twining behavior of kudzu vines.
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Affiliation(s)
- Dahye Seo
- Department of Ecology and Environmental System, Kyungpook National University, 2559 Gyeongsang-daero, Sangju 37224, Korea
| | - Junhyung Park
- Tree Diagnostic Center, Kyungpook National University, 2559 Gyeongsang-daero, Sangju 37224, Korea
| | - Ki Woo Kim
- Department of Ecology and Environmental System, Kyungpook National University, 2559 Gyeongsang-daero, Sangju 37224, Korea.,Tree Diagnostic Center, Kyungpook National University, 2559 Gyeongsang-daero, Sangju 37224, Korea
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Tavangar M, Ehsanzadeh P, Eshghizadeh H. Interplay of an array of salt-responding mechanisms in Iranian borage: Evidence from physiological, biochemical, and histochemical examinations. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 192:57-71. [PMID: 36206707 DOI: 10.1016/j.plaphy.2022.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
In order to address the lacuna of data on the response of physiological and biochemical attributes and chemical compounds of glandular trichomes of Iranian borage (Echium amoenum Fisch. & C.A.Mey.) to saline water (0, 25, 50, 75, and 100 mM NaCl) an experiment was conducted on 13 genotypes. Genotypic differences and salt-induced modifications in chlorophyll concentration and fluorescence, plant growth, relative water content, proline concentration, antioxidant defense, and chemical compounds of glandular trichomes upon exposure to salt stress were observed. Chlorophyll and carotenoids concentrations and catalase (EC 1.11.1.6) and ascorbate peroxidase (EC 1.11.1.11) activities were either enhanced or remained unchanged in the presence of moderate salt concentrations (i.e. 25 and 50 mM NaCl) in a majority of the genotypes. Though, 75 and 100 mM NaCl were modestly and severely detrimental, respectively, to the majority of the genotypes. The 75 and 100 mM NaCl led to substantial increases and decreases in the Na+ and K+, respectively, resulting in notable increase in the Na+/K+. Increases in proline, total phenolic compounds, and alkaloids concentrations, essential oils, alkaloids, and phenolic compounds of the glandular trichomes were concomitant to decreases in the relative water content, leaf area, maximum quantum efficiency of photosystem II, shoot and root dry masses. This study revealed, for the first time, that Iranian borage tolerates 25 and 50 mM NaCl and antioxidative enzymes as well as secondary metabolites such as alkaloids and phenolic compounds accumulated mainly in the trichomes play key role in this regard.
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Affiliation(s)
- Mohammad Tavangar
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Parviz Ehsanzadeh
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
| | - Hamidreza Eshghizadeh
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
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Jamal A, Wen J, Ma ZY, Ahmed I, Abdullah, Chen LQ, Nie ZL, Liu XQ. Comparative Chloroplast Genome Analyses of the Winter-Blooming Eastern Asian Endemic Genus Chimonanthus (Calycanthaceae) With Implications For Its Phylogeny and Diversification. Front Genet 2021; 12:709996. [PMID: 34917123 PMCID: PMC8670589 DOI: 10.3389/fgene.2021.709996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Chimonanthus of Calycanthaceae is a small endemic genus in China, with unusual winter-blooming sweet flowers widely cultivated for ornamentals and medicinal uses. The evolution of Chimonanthus plastomes and its phylogenetic relationships remain unresolved due to limited availability of genetic resources. Here, we report fully assembled and annotated chloroplast genomes of five Chimonanthus species. The chloroplast genomes of the genus (size range 153,010 – 153,299 bp) reveal high similarities in gene content, gene order, GC content, codon usage, amino acid frequency, simple sequence repeats, oligonucleotide repeats, synonymous and non-synonymous substitutions, and transition and transversion substitutions. Signatures of positive selection are detected in atpF and rpoB genes in C. campanulatus. The correlations among substitutions, InDels, and oligonucleotide repeats reveal weak to strong correlations in distantly related species at the intergeneric levels, and very weak to weak correlations among closely related Chimonanthus species. Chloroplast genomes are used to reconstruct a well-resolved phylogenetic tree, which supports the monophyly of Chimonanthus. Within Chimonanthus, C. praecox and C. campanulatus form one clade, while C. grammatus, C. salicifolius, C. zhejiangensis, and C. nitens constitute another clade. Chimonanthus nitens appears paraphyletic and is closely related to C. salicifolius and C. zhejiangensis, suggesting the need to reevaluate the species delimitation of C. nitens. Chimonanthus and Calycanthus diverged in mid-Oligocene; the radiation of extant Chimonanthus species was dated to the mid-Miocene, while C. grammatus diverged from other Chimonanthus species in the late Miocene. C. salicifolius, C. nitens(a), and C. zhejiangensis are inferred to have diverged in the Pleistocene of the Quaternary period, suggesting recent speciation of a relict lineage in the subtropical forest regions in eastern China. This study provides important insights into the chloroplast genome features and evolutionary history of Chimonanthus and family Calycanthaceae.
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Affiliation(s)
- Abbas Jamal
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, China
| | - Jun Wen
- Department of Botany, National Museum of Natural History, MRC166, Smithsonian Institution, Washington, DC, United States
| | - Zhi-Yao Ma
- Department of Botany, National Museum of Natural History, MRC166, Smithsonian Institution, Washington, DC, United States
| | - Ibrar Ahmed
- Alpha Genomics Private Limited, Islamabad, Pakistan
| | - Abdullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Long-Qing Chen
- Southwest Engineering Technology and Research Center of Landscape Architecture, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Ze-Long Nie
- Key Laboratory of Plant Resources Conservation and Utilization, College of Biology and Environmental Sciences, Jishou University, Jishou, China
| | - Xiu-Qun Liu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, China
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Ensikat HJ, Weigend M. Distribution of Biominerals and Mineral-Organic Composites in Plant Trichomes. Front Bioeng Biotechnol 2021; 9:763690. [PMID: 34869274 PMCID: PMC8640136 DOI: 10.3389/fbioe.2021.763690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/25/2021] [Indexed: 12/03/2022] Open
Abstract
Biomineralization is a common phenomenon in plants and has been shown to be chemically, functionally and topologically diverse. Silica and calcium carbonate have long been known as structural plant biominerals and calcium phosphate (apatite)–long known from animals–has recently been reported. Strikingly, up to three different biominerals may occur in a single trichome in, e.g., Urticaceae and Loasaceae, and in combination with organic compounds, can form organic/inorganic composite materials. This article presents an extension of previous studies on the distribution of these biominerals in Loasaceae trichomes with a focus on their spatial (three-dimensional) distribution and co-localization with organic substances. Light microscopy and scanning electron microscopy with high-resolution EDX element analyses of sample surfaces and sections illustrate the differential distribution and composition of the different biomineral phases across cell surfaces and cell walls. Raman spectroscopy additionally permits the identification of organic and inorganic compounds side by side. All three biominerals may be found in a nearly pure inorganic phase, e.g., on the plant surfaces and in the barbs of the glochidiate trichomes, or in combination with a larger proportion of organic compounds (cellulose, pectin). The cell lumen may be additionally filled with amorphous mineral deposits. Water-solubility of the mineral fractions differs considerably. Plant trichomes provide an exciting model system for biomineralization and enable the in-vivo study of the formation of complex composite materials with different biomineral and organic compounds involved.
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Medina MC, Sousa-Baena MS, Capelli NDV, Koch R, Demarco D. Stinging Trichomes in Apocynaceae and Their Evolution in Angiosperms. PLANTS (BASEL, SWITZERLAND) 2021; 10:2324. [PMID: 34834691 PMCID: PMC8624652 DOI: 10.3390/plants10112324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/21/2021] [Accepted: 10/21/2021] [Indexed: 05/11/2023]
Abstract
Stinging trichomes are rare in plants, occurring only in angiosperms, where they are reported for a few genera belonging to six families. Although there is no report of stinging trichomes in Apocynaceae, previous fieldwork collections of Fischeria and Matelea caused us a mild allergic reaction on the skin when we contacted the dense indumentum of the plants. This fact associated with the well-known presence of glandular trichomes with acute apex in both genera raised suspicions that stinging trichomes could be present in the family. Hence, this study aimed to investigate the likely occurrence of stinging trichomes in Fischeria and Matelea. We analyzed vegetative shoots and leaves of Fischeria stellata and Matelea denticulata through the usual procedures of light and scanning electron microscopy. We also performed several histochemical tests to investigate the chemical composition of trichome secretion. We detected that glandular trichomes occur throughout the surface of the leaf and stem. They are multicellular, uniseriate with an apical secretory cell, which has a dilated base and a needle-shaped apex. The secretion is compressed into the acuminate portion of the apical cell by a large vacuole, and crystals are deposited in the cell wall in a subapical position, providing a preferential site of rupture. The secretion, composed of amino acids and/or proteins, is released under mechanical action, causing skin irritation. Based on our detailed morphological and anatomical analyses, and in the functional aspects observed, we concluded that the glandular trichomes in Fischeria and Matelea can indeed be classified as stinging. Thus, Apocynaceae is the seventh family for which this type of trichome has been reported. We also compiled information on stinging trichomes in all families of angiosperms. Their phylogenetic distribution indicates that they have evolved at least 12 times during angiosperm evolution and may represent an evolutionary convergence of plant defense against herbivory.
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Affiliation(s)
| | | | | | | | - Diego Demarco
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, SP, Brazil; (M.C.M.); (M.S.S.-B.); (N.d.V.C.); (R.K.)
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Hopewell T, Selvi F, Ensikat HJ, Weigend M. Trichome Biomineralization and Soil Chemistry in Brassicaceae from Mediterranean Ultramafic and Calcareous Soils. PLANTS 2021; 10:plants10020377. [PMID: 33671132 PMCID: PMC7923191 DOI: 10.3390/plants10020377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 11/24/2022]
Abstract
Trichome biomineralization is widespread in plants but detailed chemical patterns and a possible influence of soil chemistry are poorly known. We explored this issue by investigating trichome biomineralization in 36 species of Mediterranean Brassicaceae from ultramafic and calcareous soils. Our aims were to chemically characterize biomineralization of different taxa, including metallophytes, under natural conditions and to investigate whether divergent Ca, Mg, Si and P-levels in the soil are reflected in trichome biomineralization and whether the elevated heavy metal concentrations lead to their integration into the mineralized cell walls. Forty-two samples were collected in the wild while a total of 6 taxa were brought into cultivation and grown in ultramafic, calcareous and standard potting soils in order to investigate an effect of soil composition on biomineralization. The sampling included numerous known hyperaccumulators of Ni. EDX microanalysis showed CaCO3 to be the dominant biomineral, often associated with considerable proportions of Mg—independent of soil type and wild versus cultivated samples. Across 6 of the 9 genera studied, trichome tips were mineralized with calcium phosphate, in Bornmuellera emarginata the P to Ca-ratio was close to that of pure apatite-calcium phosphate (Ca5(PO4)3OH). A few samples also showed biomineralization with Si, either only at the trichome tips or all over the trichome. Additionally, we found traces of Mn co-localized with calcium phosphate in Bornmuellera emarginata and traces of Ni were detected in trichomes of the Ni-hyperaccumulator Odontarrhena chalcidica. Our data from wild and cultivated plants could not confirm any major effect of soil chemistry on the chemistry of trichome biominerals. Hyperaccumulation of Ni in the plants is not mirrored in high levels of Ni in the trichomes, nor do we find large amounts of Mn. A comparison based on plants from cultivation (normal, calcareous and serpentine soils, Mg:Ca-ratios ca 1:2 to 1:20) shows at best a very weak reflection of different Mg:Ca-ratios in the mineralized trichomes. The plants studied seem to be able to maintain highly conserved biomineralization patterns across a wide range of soil chemistries.
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Affiliation(s)
- Tyler Hopewell
- Nees-Institut für Biodiversität der Pflanzen, Meckenheimer Allee 170, D-53115 Bonn, Germany; (H.-J.E.); (M.W.)
- Correspondence:
| | - Federico Selvi
- Laboratori di Botanica, Dipartimento di Scienze Agrarie, Alimentari, Ambientali e Forestali, Università di Firenze, P.le Cascine 28, I-50144 Firenze, Italy;
| | - Hans-Jürgen Ensikat
- Nees-Institut für Biodiversität der Pflanzen, Meckenheimer Allee 170, D-53115 Bonn, Germany; (H.-J.E.); (M.W.)
| | - Maximilian Weigend
- Nees-Institut für Biodiversität der Pflanzen, Meckenheimer Allee 170, D-53115 Bonn, Germany; (H.-J.E.); (M.W.)
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Matinzadeh Z, Akhani H, Abedi M, Palacio S. The elemental composition of halophytes correlates with key morphological adaptations and taxonomic groups. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 141:259-278. [PMID: 31200272 DOI: 10.1016/j.plaphy.2019.05.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 05/11/2023]
Abstract
Halophytes are crucial in the light of increasing soil salinization, yet our understanding of their chemical composition and its relationship to key morphological traits such as succulence or salt excretion is limited. This study targets this issue by exploring the relationship between the elemental composition of 108 plant species from saline environments in Iran and their eco-morphological traits and taxonomy. Leaves and/or photosynthetic shoots of individual species and soils were sampled and analyzed for 20 elements in plant samples and 5 major elements plus % gypsum content, pH, and EC in soil samples. Eu-halophytes and leaf- and stem-succulent and salt-recreting plants showed high concentrations of Na, S, and Mg and low concentrations of Ca and K. In contrast, pseudo-halophytes, facultative-halophytes and eury-hygro-halophytes, which often lack succulent shoots, showed low Na, S, and Mg and high Ca and K concentrations in their leaves. Clear patterns were identified among taxonomic families, with Chenopodiaceae and Plumbaginaceae having high Na and Mg and low Ca and K concentrations, Caryophyllaceae having high K, Poaceae having low Na, and Asteraceae, Boraginaceae, and Brassicaceae showing high foliar Ca concentrations. We conclude that the elemental composition of halophytes and pseudo-halophytes is related to salt-tolerance categories, eco-morphological types and respective taxonomic groups.
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Affiliation(s)
- Zeinab Matinzadeh
- Halophytes and C(4) Plants Research Laboratory, Department of Plant Sciences, School of Biology, College of Science, University of Tehran, P.O.Box, 14155-6455, Tehran, Iran
| | - Hossein Akhani
- Halophytes and C(4) Plants Research Laboratory, Department of Plant Sciences, School of Biology, College of Science, University of Tehran, P.O.Box, 14155-6455, Tehran, Iran.
| | - Mehdi Abedi
- Department of Range Management, Faculty of Natural Resources, Tarbiat Modares University, 46417-76489, Noor, Iran
| | - Sara Palacio
- Instituto Pirenaico de Ecología (IPE-CSIC), Av. Nuestra Señora de la Victoria, 16, 22700, Jaca, Huesca, Spain
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Matthus E, Wilkins KA, Swarbreck SM, Doddrell NH, Doccula FG, Costa A, Davies JM. Phosphate Starvation Alters Abiotic-Stress-Induced Cytosolic Free Calcium Increases in Roots. PLANT PHYSIOLOGY 2019; 179:1754-1767. [PMID: 30696750 PMCID: PMC6446763 DOI: 10.1104/pp.18.01469] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 01/17/2019] [Indexed: 05/08/2023]
Abstract
Phosphate (Pi) deficiency strongly limits plant growth, and plant roots foraging the soil for nutrients need to adapt to optimize Pi uptake. Ca2+ is known to signal in root development and adaptation but has to be tightly controlled, as it is highly toxic to Pi metabolism. Under Pi starvation and the resulting decreased cellular Pi pool, the use of cytosolic free Ca2+ ([Ca2+]cyt) as a signal transducer may therefore have to be altered. Employing aequorin-expressing Arabidopsis (Arabidopsis thaliana), we show that Pi starvation, but not nitrogen starvation, strongly dampens the [Ca2+]cyt increases evoked by mechanical, salt, osmotic, and oxidative stress as well as by extracellular nucleotides. The altered root [Ca2+]cyt response to extracellular ATP manifests during seedling development under chronic Pi deprivation but can be reversed by Pi resupply. Employing ratiometric imaging, we delineate that Pi-starved roots have a normal response to extracellular ATP at the apex but show a strongly dampened [Ca2+]cyt response in distal parts of the root tip, correlating with high reactive oxygen species levels induced by Pi starvation. Excluding iron, as well as Pi, rescues this altered [Ca2+]cyt response and restores reactive oxygen species levels to those seen under nutrient-replete conditions. These results indicate that, while Pi availability does not seem to be signaled through [Ca2+]cyt, Pi starvation strongly affects stress-induced [Ca2+]cyt signatures. These data reveal how plants can integrate nutritional and environmental cues, adding another layer of complexity to the use of Ca2+ as a signal transducer.
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Affiliation(s)
- Elsa Matthus
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Katie A Wilkins
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Stéphanie M Swarbreck
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Nicholas H Doddrell
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | | | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy
| | - Julia M Davies
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
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11
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Mustafa A, Ensikat HJ, Weigend M. Stinging hair morphology and wall biomineralization across five plant families: Conserved morphology versus divergent cell wall composition. AMERICAN JOURNAL OF BOTANY 2018; 105:1109-1122. [PMID: 30080249 DOI: 10.1002/ajb2.1136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Stinging hairs are striking examples of plant microengineering-the plant equivalent of the hypodermic syringe. The requisite mechanical properties are mostly achieved by cell wall mineralization. Stinging hairs of Urtica dioica (Urticaceae) are known to be mineralized with silica and calcium carbonate and those of Loasaceae also with calcium phosphate, but no comparative study has been provided across different taxa with stinging hairs. METHODS Light microscopy and scanning electron microscopy (SEM) with cryo-SEM and energy-dispersive x-ray spectroscopy were used to analyze morphology and biomineralization of stinging hairs of 43 species from the families Caricaceae, Euphorbiaceae, Loasaceae, Namaceae, and Urticaceae. KEY RESULTS Stinging hair morphology is similar across the taxa studied, in striking contrast to the divergent patterns of biomineralization. Trichome bases are mostly calcified, sometimes silicified, the shafts are mostly calcified, and the apices silicified (Urticaceae), and contain calcium phosphate (Caricaceae, Namaceae), both silica and calcium phosphate (some Loasaceae), or no minerals (Cnidoscolus, Euphorbiaceae). Some stinging hairs are superficially thinly coated with silica over a cell wall otherwise mineralized with calcium carbonate or calcium phosphate. CONCLUSIONS Mineralization patterns are surprisingly diverse and involve three different biominerals deposited in different parts of individual trichomes with calcium phosphate a common component. The physical properties of different wall regions of the stinging trichomes are thus fine-tuned to optimize their function via modulation of wall thickness and differential element deposition. Similar function is apparently achieved through divergent wall compositions.
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Affiliation(s)
- Adeel Mustafa
- Nees-Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, D-53115, Bonn, Germany
| | - Hans-Jürgen Ensikat
- Nees-Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, D-53115, Bonn, Germany
| | - Maximilian Weigend
- Nees-Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, D-53115, Bonn, Germany
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