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Palakurthy S, Houben L, Elbaum M, Elbaum R. Silica Biomineralization with Lignin Involves Si-O-C Bonds That Stabilize Radicals. Biomacromolecules 2024. [PMID: 38713166 DOI: 10.1021/acs.biomac.4c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Plants undergo substantial biomineralization of silicon, which is deposited primarily in cell walls as amorphous silica. The mineral formation could be moderated by the structure and chemistry of lignin, a polyphenol polymer that is a major constituent of the secondary cell wall. However, the reactions between lignin and silica have not yet been well elucidated. Here, we investigate silica deposition onto a lignin model compound. Polyphenyl propanoid was synthesized from coniferyl alcohol by oxidative coupling with peroxidase in the presence of acidic tetramethyl orthosilicate, a silicic acid precursor. Raman, Fourier transform infrared, and X-ray photoelectron spectroscopies detected changes in lignin formation in the presence of silicic acid. Bonds between the Si-O/Si-OH residues and phenoxyl radicals and lignin functional groups formed during the first 3 h of the reaction, while silica continued to form over 3 days. Thermal gravimetric analysis indicated that lignin yields increased in the presence of silicic acid, possibly via the stabilization of phenolic radicals. This, in turn, resulted in shorter stretches of the lignin polymer. Silica deposition initiated within a lignin matrix via the formation of covalent Si-O-C bonds. The silica nucleants grew into 2-5 nm particles, as observed via scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Additional silica precipitated into an extended gel. Collectively, our results demonstrate a reciprocal relation by which lignin polymerization catalyzes the formation of silica, and at the same time silicic acid enhances lignin polymerization and yield.
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Affiliation(s)
- Srinath Palakurthy
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
| | - Lothar Houben
- The Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Michael Elbaum
- The Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
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Mukarram M, Ahmad B, Choudhary S, Konôpková AS, Kurjak D, Khan MMA, Lux A. Silicon nanoparticles vs trace elements toxicity: Modus operandi and its omics bases. FRONTIERS IN PLANT SCIENCE 2024; 15:1377964. [PMID: 38633451 PMCID: PMC11021597 DOI: 10.3389/fpls.2024.1377964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/18/2024] [Indexed: 04/19/2024]
Abstract
Phytotoxicity of trace elements (commonly misunderstood as 'heavy metals') includes impairment of functional groups of enzymes, photo-assembly, redox homeostasis, and nutrient status in higher plants. Silicon nanoparticles (SiNPs) can ameliorate trace element toxicity. We discuss SiNPs response against several essential (such as Cu, Ni, Mn, Mo, and Zn) and non-essential (including Cd, Pb, Hg, Al, Cr, Sb, Se, and As) trace elements. SiNPs hinder root uptake and transport of trace elements as the first line of defence. SiNPs charge plant antioxidant defence against trace elements-induced oxidative stress. The enrolment of SiNPs in gene expressions was also noticed on many occasions. These genes are associated with several anatomical and physiological phenomena, such as cell wall composition, photosynthesis, and metal uptake and transport. On this note, we dedicate the later sections of this review to support an enhanced understanding of SiNPs influence on the metabolomic, proteomic, and genomic profile of plants under trace elements toxicity.
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Affiliation(s)
- Mohammad Mukarram
- Food and Plant Biology Group, Department of Plant Biology, School of Agriculture, Universidad de la Republica, Montevideo, Uruguay
- Department of Phytology, Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovakia
| | - Bilal Ahmad
- Plant Physiology Section, Department of Botany, Government Degree College for Women, Pulwama, Jammu and Kashmir, India
| | - Sadaf Choudhary
- Advance Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Alena Sliacka Konôpková
- Department of Integrated Forest and Landscape Protection, Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovakia
- Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovakia
| | - Daniel Kurjak
- Department of Integrated Forest and Landscape Protection, Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovakia
- Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovakia
| | - M. Masroor A. Khan
- Advance Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Alexander Lux
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
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Zexer N, Diehn S, Elbaum R. Deposition of silica in sorghum root endodermis modifies the chemistry of associated lignin. FRONTIERS IN PLANT SCIENCE 2024; 15:1370479. [PMID: 38633454 PMCID: PMC11021652 DOI: 10.3389/fpls.2024.1370479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/05/2024] [Indexed: 04/19/2024]
Abstract
Silica aggregates at the endodermis of sorghum roots. Aggregation follows a spotted pattern of locally deposited lignin at the inner tangential cell walls. Autofluorescence microscopy suggests that non-silicified (-Si) lignin spots are composed of two distinct concentric regions of varied composition. To highlight variations in lignin chemistry, we used Raman microspectroscopy to map the endodermal cell wall and silica aggregation sites in sorghum roots grown hydroponically with or without Si amendment. In +Si samples, the aggregate center was characterized by typical lignin monomer bands surrounded by lignin with a low level of polymerization. Farther from the spot, polysaccharide concentration increased and soluble silicic acid was detected in addition to silica bands. In -Si samples, the main band at the spot center was assigned to lignin radicals and highly polymerized lignin. Both +Si and -Si loci were enriched by aromatic carbonyls. We propose that at silica aggregation sites, carbonyl rich lignin monomers are locally exported to the apoplast. These monomers are radicalized and polymerized into short lignin polymers. In the presence of silicic acid, bonds typically involved in lignin extension, bind to silanols and nucleate silica aggregates near the monomer extrusion loci. This process inhibits further polymerization of lignin. In -Si samples, the monomers diffuse farther in the wall and crosslink with cell wall polymers, forming a ring of dense lignified cell wall around their export sites.
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Affiliation(s)
- Nerya Zexer
- Department of Biology, The Pennsylvania State University, University Park, PA, United States
| | - Sabrina Diehn
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
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Dabravolski SA, Isayenkov SV. The Physiological and Molecular Mechanisms of Silicon Action in Salt Stress Amelioration. PLANTS (BASEL, SWITZERLAND) 2024; 13:525. [PMID: 38498577 PMCID: PMC10893008 DOI: 10.3390/plants13040525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/20/2024]
Abstract
Salinity is one of the most common abiotic stress factors affecting different biochemical and physiological processes in plants, inhibiting plant growth, and greatly reducing productivity. During the last decade, silicon (Si) supplementation was intensively studied and now is proposed as one of the most convincing methods to improve plant tolerance to salt stress. In this review, we discuss recent papers investigating the role of Si in modulating molecular, biochemical, and physiological processes that are negatively affected by high salinity. Although multiple reports have demonstrated the beneficial effects of Si application in mitigating salt stress, the exact molecular mechanism underlying these effects is not yet well understood. In this review, we focus on the localisation of Si transporters and the mechanism of Si uptake, accumulation, and deposition to understand the role of Si in various relevant physiological processes. Further, we discuss the role of Si supplementation in antioxidant response, maintenance of photosynthesis efficiency, and production of osmoprotectants. Additionally, we highlight crosstalk of Si with other ions, lignin, and phytohormones. Finally, we suggest some directions for future work, which could improve our understanding of the role of Si in plants under salt stress.
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Affiliation(s)
- Siarhei A. Dabravolski
- Department of Biotechnology Engineering, Braude Academic College of Engineering, Snunit 51, Karmiel 2161002, Israel;
| | - Stanislav V. Isayenkov
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Betty-Heimann-Strasse 3, 06120 Halle, Germany
- Department of Plant Food Products and Biofortification, Institute of Food Biotechnology and Genomics, The National Academy of Sciences of Ukraine, Baidi-Vyshneveckogo Str. 2a, 04123 Kyiv, Ukraine
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Ayieko VO, Cohen L, Diehn S, Goobes G, Elbaum R. Siliplant1 B-domain precipitates silica spheres, aggregates, or gel, depending on Si-precursor to peptide ratios. Colloids Surf B Biointerfaces 2023; 232:113582. [PMID: 37862949 DOI: 10.1016/j.colsurfb.2023.113582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/22/2023]
Abstract
Silica is extensively deposited by plants, however, only little is known about the molecular control over this process. Siliplant1 is the only known plant protein to precipitate biosilica. The protein contains seven repeats made of three domains. One of the domains exhibits a conserved sequence, which catalyzes silica precipitation in vitro. Here, silica was synthesized by the activity of a peptide carrying this conserved sequence. Infrared spectroscopy and thermal gravimetric analyses showed that the peptide was bound to the mineral. Scanning electron microscopy showed that silica-peptide particles of 22 ± 4 nm aggregated to spherical structures of 200-300 nm when the ratio of silicic acid to the peptide was below 183:1 molecules. When the ratio was about 183:1, similar particles aggregated into irregular structures, and silica gel formed at higher ratios. Solid-state NMR spectra indicated that the irregular aggregates were richer in Si-O-Si bonds as well as disordered peptide. Our results suggest that the peptide catalyzed the condensation of silicic acid and the formation of ∼20 nm particles, which aggregated into spheres. Excess of the peptide stabilized surface Si-OH groups that prevented spontaneous Si-O-Si bonding between aggregates. Under Si concentrations relevant to plant sap, the peptide and possibly Siliplant1, could catalyze nucleation of silica particles that aggregate into spherical aggregates.
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Affiliation(s)
- Vincent Otieno Ayieko
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
| | - Lilian Cohen
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Sabrina Diehn
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
| | - Gil Goobes
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel.
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Veber A, Zancajo VMR, Puskar L, Schade U, Kneipp J. In situ infrared imaging of the local orientation of cellulose fibrils in plant secondary cell walls. Analyst 2023; 148:4138-4147. [PMID: 37496329 DOI: 10.1039/d3an00897e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The mechanical and chemical properties of plant cell walls greatly rely on the supramolecular assembly of cellulose fibrils. To study the local orientation of cellulose in secondary plant cell walls, diffraction limited infrared (IR) micro-spectroscopic mapping experiments were conducted at different orientation of transverse leaf section of the grass Sorghum bicolor with respect to the polarization direction of the IR radiation. Two-dimensional maps, based on polarization-sensitive absorption bands of cellulose were obtained for different polarization angles. They reveal a significant degree of anisotropy of the cellulose macromolecules as well as of other biopolymers in sclerenchyma and xylem regions of the cross section. Quantification of the signals assigned to polarization sensitive vibrational modes allowed to determine the preferential orientation of the sub-micron cellulose fibrils in single cell walls. A sample of crystalline nano-cellulose comprising both a single microcrystal as well as unordered layers of nanocrystals was used for validation of the approach. The results demonstrate that diffraction limited IR micro-spectroscopy can be used to study hierarchically structured materials with complex anisotropic behavior.
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Affiliation(s)
- Alexander Veber
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Victor M R Zancajo
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
| | - Ljiljana Puskar
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Ulrich Schade
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Janina Kneipp
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
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Zexer N, Kumar S, Elbaum R. Silica deposition in plants: scaffolding the mineralization. ANNALS OF BOTANY 2023; 131:897-908. [PMID: 37094329 PMCID: PMC10332400 DOI: 10.1093/aob/mcad056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/20/2023] [Indexed: 05/03/2023]
Abstract
BACKGROUND Silicon and aluminium oxides make the bulk of agricultural soils. Plants absorb dissolved silicon as silicic acid into their bodies through their roots. The silicic acid moves with transpiration to target tissues in the plant body, where it polymerizes into biogenic silica. Mostly, the mineral forms on a matrix of cell wall polymers to create a composite material. Historically, silica deposition (silicification) was supposed to occur once water evaporated from the plant surface, leaving behind an increased concentration of silicic acid within plant tissues. However, recent publications indicate that certain cell wall polymers and proteins initiate and control the extent of plant silicification. SCOPE Here we review recent publications on the polymers that scaffold the formation of biogenic plant silica, and propose a paradigm shift from spontaneous polymerization of silicic acid to dedicated active metabolic processes that control both the location and the extent of the mineralization. CONCLUSION Protein activity concentrates silicic acid beyond its saturation level. Polymeric structures at the cell wall stabilize the supersaturated silicic acid and allow its flow with the transpiration stream, or bind it and allow its initial condensation. Silica nucleation and further polymerization are enabled on a polymeric scaffold, which is embedded within the mineral. Deposition is terminated once free silicic acid is consumed or the chemical moieties for its binding are saturated.
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Affiliation(s)
- Nerya Zexer
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Santosh Kumar
- Department of Biological Sciences, Birla Institute of Technology and Science-Pilani, K. K. Birla Goa Campus, Zuarinagar 403726, Goa, India
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, Odisha, India
| | - Rivka Elbaum
- R. H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 7610001, Israel
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Vidya CSN, Shetty R, Bokor B, Fialová I, Luxová M, Jašková K, Vaculík M. Do Antimonite and Silicon Share the Same Root Uptake Pathway by Lsi1 in Sorghum bicolor L. Moench? PLANTS (BASEL, SWITZERLAND) 2023; 12:2368. [PMID: 37375993 DOI: 10.3390/plants12122368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/18/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023]
Abstract
A study was conducted to further develop our understanding of antimony (Sb) uptake in plants. Unlike other metal(loid)s, such as silicon (Si), the mechanisms of Sb uptake are not well understood. However, SbIII is thought to enter the cell via aquaglyceroporins. We investigated if the channel protein Lsi1, which aids in Si uptake, also plays a role in Sb uptake. Seedlings of WT sorghum, with normal silicon accumulation, and its mutant (sblsi1), with low silicon accumulation, were grown in Hoagland solution for 22 days in the growth chamber under controlled conditions. Control, Sb (10 mg Sb L-1), Si (1mM) and Sb + Si (10 mg Sb L-1 + 1 mM Si) were the treatments. After 22 days, root and shoot biomass, the concentration of elements in root and shoot tissues, lipid peroxidation and ascorbate levels, and relative expression of Lsi1 were determined. When mutant plants were exposed to Sb, they showed almost no toxicity symptoms compared to WT plants, indicating that Sb was not toxic to mutant plants. On the other hand, WT plants had decreased root and shoot biomass, increased MDA content and increased Sb uptake compared to mutant plants. In the presence of Sb, we also found that SbLsi1 was downregulated in the roots of WT plants. The results of this experiment support the role of Lsi1 in Sb uptake in sorghum plants.
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Affiliation(s)
- Chirappurathu Sukumaran Nair Vidya
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
| | - Rajpal Shetty
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B2, Ilkovicova 6, SK-842 15 Bratislava, Slovakia
| | - Boris Bokor
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B2, Ilkovicova 6, SK-842 15 Bratislava, Slovakia
- Comenius University Science Park, SK-841 04 Bratislava, Slovakia
| | - Ivana Fialová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
| | - Miroslava Luxová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
| | - Katarína Jašková
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
| | - Marek Vaculík
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B2, Ilkovicova 6, SK-842 15 Bratislava, Slovakia
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Sheng H, Li Y, Feng J, Liu Y. Regulation of thermodynamics and kinetics of silica nucleation during the silicification process in higher plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 198:107674. [PMID: 37018864 DOI: 10.1016/j.plaphy.2023.107674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/09/2023] [Accepted: 03/27/2023] [Indexed: 05/07/2023]
Abstract
The formation mechanism of SiO2 aggregates is controversial because two contrasting hypotheses are often proposed to explain plant silicification. In this review, we summarize the physicochemical fundamentals of amorphous silica nucleation and discuss how plants regulate the process of silicification by influencing the thermodynamics and kinetics of silica nucleation. At silicification positions, plants overcome the thermodynamic barrier by establishing the supersaturation of the H4SiO4 solution and reducing the interfacial free energy. Among the thermodynamic-drivers, the establishment of supersaturation of H4SiO4 solution mainly depends on the expression of Si transporters for H4SiO4 supply, evapotranspiration for concentrating Si, and the other solutes in H4SiO4 solution for influencing the dissolution equilibrium of SiO2; while the interfacial free energy was reduced seemingly by the overexpression Na+/H+ antiporter SOS1 in high NaCl-stressed rice. Moreover, some kinetic-drivers, such as silicification-related proteins (Slp1 and PRP1) and new cell wall components, are actively expressed or synthesized by plants to interact with silicic acid, thereby reducing the kinetic barrier. According to classical nucleation theory, when the thermodynamic barrier is overcome, the super-saturated silicic acid solution (such as H4SiO4 in xylem sap) does not necessarily have to precipitate, just has the potential ability to precipitation. Thus, based on the mediators of SiO2 deposition at the thermodynamic-driven stage, it is difficult to evaluate whether the process of plant silicification is active or passive. We conclude that the characteristics of kinetic-drivers determine the mechanism of plant silicification.
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Affiliation(s)
- Huachun Sheng
- Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Tibetan Plateau Ethnic Medicinal Resources Protection and Utilization Key Laboratory of National Ethnic Affairs Commission of the People's Republic of China, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Sichuan Provincial Qiang-Yi Medicinal Resources Protection and Utilization Technology and Engineering Laboratory, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China.
| | - Ying Li
- Tibetan Plateau Ethnic Medicinal Resources Protection and Utilization Key Laboratory of National Ethnic Affairs Commission of the People's Republic of China, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Sichuan Provincial Qiang-Yi Medicinal Resources Protection and Utilization Technology and Engineering Laboratory, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; College of Pharmacy, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China
| | - Jingqiu Feng
- Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Tibetan Plateau Ethnic Medicinal Resources Protection and Utilization Key Laboratory of National Ethnic Affairs Commission of the People's Republic of China, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Sichuan Provincial Qiang-Yi Medicinal Resources Protection and Utilization Technology and Engineering Laboratory, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China.
| | - Yuan Liu
- Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Tibetan Plateau Ethnic Medicinal Resources Protection and Utilization Key Laboratory of National Ethnic Affairs Commission of the People's Republic of China, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China; Sichuan Provincial Qiang-Yi Medicinal Resources Protection and Utilization Technology and Engineering Laboratory, Southwest Minzu University, Chengdu, Sichuan, 610225, PR China.
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Nikolić D, Bosnić D, Samardžić J. Silicon in action: Between iron scarcity and excess copper. FRONTIERS IN PLANT SCIENCE 2023; 14:1039053. [PMID: 36818840 PMCID: PMC9935840 DOI: 10.3389/fpls.2023.1039053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Essential micronutrients belonging to the transition metals, such as Fe and Cu, are indispensable for plant growth and stress tolerance; however, when present in excess, they can become potentially dangerous producers of reactive oxygen species. Therefore, their homeostases must be strictly regulated. Both microelement deficiencies and elevated concentrations of heavy metals in the soil are global problems that reduce the nutritional value of crops and seriously affect human health. Silicon, a beneficial element known for its protective properties, has been reported to alleviate the symptoms of Cu toxicity and Fe deficiency stress in plants; however, we are still far from a comprehensive understanding of the underlying molecular mechanisms. Although Si-mediated mitigation of these stresses has been clearly demonstrated for some species, the effects of Si vary depending on plant species, growing conditions and experimental design. In this review, the proposed mechanistic models explaining the effect of Si are summarized and discussed. Iron and copper compete for the common metal transporters and share the same transport routes, hence, inadequate concentration of one element leads to disturbances of another. Silicon is reported to beneficially influence not only the distribution of the element supplied below or above the optimal concentration, but also the distribution of other microelements, as well as their molar ratios. The influence of Si on Cu immobilization and retention in the root, as well as Si-induced Fe remobilization from the source to the sink organs are of vital importance. The changes in cellular Cu and Fe localization are considered to play a crucial role in restoring homeostasis of these microelements. Silicon has been shown to stimulate the accumulation of metal chelators involved in both the mobilization of deficient elements and scavenging excess heavy metals. Research into the mechanisms of the ameliorative effects of Si is valuable for reducing mineral stress in plants and improving the nutritional value of crops. This review aims to provide a thorough and critical overview of the current state of knowledge in this field and to discuss discrepancies in the observed effects of Si and different views on its mode of action.
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Rivai RR, Miyamoto T, Awano T, Yoshinaga A, Chen S, Sugiyama J, Tobimatsu Y, Umezawa T, Kobayashi M. Limiting silicon supply alters lignin content and structures of sorghum seedling cell walls. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 321:111325. [PMID: 35696925 DOI: 10.1016/j.plantsci.2022.111325] [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: 11/13/2021] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Sorghum has been recognized as a promising energy crop. The composition and structure of lignin in the cell wall are important factors that affect the quality of plant biomass as a bioenergy feedstock. Silicon (Si) supply may affect the lignin content and structure, as both Si and lignin are possibly involved in plant mechanical strength. However, our understanding regarding the interaction between Si and lignin in sorghum is limited. Therefore, in this study, we analyzed the lignin in the cell walls of sorghum seedlings cultured hydroponically with or without Si supplementation. Limiting the Si supply significantly increased the thioglycolic acid lignin content and thioacidolysis-derived syringyl/guaiacyl monomer ratio. At least part of the modification may be attributable to the change in gene expression, as suggested by the upregulation of phenylpropanoid biosynthesis-related genes under -Si conditions. The cell walls of the -Si plants had a higher mechanical strength and calorific value than those of the +Si plants. These results provide some insights into the enhancement of the value of sorghum biomass as a feedstock for energy production by limiting Si uptake.
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Affiliation(s)
- Reza Ramdan Rivai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan; National Research and Innovation Agency of the Republic of Indonesia, Bogor, Indonesia
| | - Takuji Miyamoto
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan
| | - Tatsuya Awano
- Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Arata Yoshinaga
- Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Shuoye Chen
- Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Junji Sugiyama
- Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yuki Tobimatsu
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan
| | - Toshiaki Umezawa
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan
| | - Masaru Kobayashi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
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Srivastava A, Sharma VK, Kaushik P, El-Sheikh MA, Qadir S, Mansoor S. Effect of silicon application with mycorrhizal inoculation on Brassica juncea cultivated under water stress. PLoS One 2022; 17:e0261569. [PMID: 35389996 PMCID: PMC8989204 DOI: 10.1371/journal.pone.0261569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 12/05/2021] [Indexed: 11/18/2022] Open
Abstract
Brassica juncea L. is a significant member of the Brassicaceae family, also known as Indian mustard. Water is a limiting factor in the successful production of this crop. Here, we tested the effect of water shortage in B. juncea plants supplemented with or without the application of silicon and arbuscular mycorrhizal fungi in total 8 different treatments compared under open filed conditions using a randomised complete block design (RCBD). The treatments under control conditions were control (C, T1); C+Silicon (Si, T2); C+My (Mycorrhiza; T3); and C+Si+My (T4). In contrast, treatments under stress conditions were S (Stress; T5); S+Si (T6); S+My (T7) and S+Si+My (T8), respectively. In total, we evaluated 16 traits, including plant response to stress by evaluating peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activity. The fresh weight (g) increased only 7.47 percent with mycorrhiza (C+My) and 22.39 percent with silicon (C+Si) but increased 291.08 percent with both mycorrhiza and silicon (C+Si+My). Using mycorrhiza (S+My) or silicon (S+Si) alone produced a significant increase of 53.16 percent and 55.84 percent in fresh weight, respectively, while using both mycorrhiza and silicon (S+Si+My) together produced a dramatic increase of 380.71 percent under stress conditions. Superoxidase dismutase concentration (Ug−1 FW) was found to be increased by 29.48 percent, 6.71 percent, and 22.63 percent after applying C+My, C+Si and C+Si+My, but treatment under stress revealed some contrasting trends, with an increase of 11.21 percent and 19.77 percent for S+My, S+Si+My, but a decrease of 13.15 percent for S+Si. Finally, in the presence of stress, carotenoid content (mg/g FW) increased by 58.06 percent, 54.83 percent, 183.87 percent with C+My, and 23.81 percent with S+My and S+Si+My, but decreased by 22.22 percent with S+Si. Silicon application proved to be more effective than AMF treatment with Rhizophagus irregularis, and the best results were obtained with the combination of Si and AMF. This work will help to suggest the measures to overcome the water stress in B. juncea.
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Affiliation(s)
- Ashutosh Srivastava
- Department of Botany, Rani Lakshmi Bai Central Agricultural University, Jhansi, Uttar Pradesh
| | - Vijay Kumar Sharma
- Department Genetics and Plant Breeding, Banda University of Agriculture and Technology, Banda, Uttar Pradesh, India
| | - Prashant Kaushik
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain
- * E-mail: ,
| | - Mohamed A. El-Sheikh
- Botany and Microbiology Department College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Shaista Qadir
- Department of Botany, Womens College, Srinagar, Jammu and Kashmir, India
| | - Sheikh Mansoor
- Division of Biochemistry FBSc, SKUAST Jammu J&K, Jammu and Kashmir, India
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13
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Zexer N, Elbaum R. Hydrogen peroxide modulates silica deposits in sorghum roots. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1450-1463. [PMID: 34791152 DOI: 10.1093/jxb/erab497] [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: 07/08/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Hydrated silica (SiO2·nH2O) aggregates in the root endodermis of grasses. Application of soluble silicates (Si) to roots is associated with variations in the balance of reactive oxygen species (ROS), increased tolerance to a broad range of stresses affecting ROS concentrations, and early lignin deposition. In sorghum (Sorghum bicolor L.), silica aggregation is patterned in an active silicification zone (ASZ) by a special type of aromatic material forming a spotted pattern. The deposition has a signature typical of lignin. Since lignin polymerization is mediated by ROS, we studied the formation of root lignin and silica controlled by ROS via modulating hydrogen peroxide (H2O2) concentrations in the growth medium. Sorghum seedlings were grown hydroponically and supplemented with Si, H2O2, and KI, an ionic compound that catalyses H2O2 decomposition. Lignin and silica deposits in the endodermis were studied by histology, scanning electron and Raman microscopies. Cell wall composition was quantified by thermal gravimetric analysis. Endodermal H2O2 concentration correlated to the extent of lignin-like deposition along the root, but did not affect its patterning in spots. Our results show that the ASZ spots were necessary for root silica aggregation, and suggest that silicification is intensified under oxidative stress as a result of increased ASZ lignin-like deposition.
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Affiliation(s)
- Nerya Zexer
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
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14
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Radotić K, Đikanović D, Kalauzi A, Tanasijević G, Maksimović V, Dragišić Maksimović J. Influence of silicon on polymerization process during lignin synthesis. Implications for cell wall properties. Int J Biol Macromol 2021; 198:168-174. [PMID: 34968543 DOI: 10.1016/j.ijbiomac.2021.12.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/09/2021] [Accepted: 12/21/2021] [Indexed: 12/20/2022]
Abstract
Silicon (Si) is considered a beneficial element for plants, mostly accumulating in cell walls, where its location and content are primed by the chemistry and structure of lignin. It is unrevealed how Si interacts with the process of lignin formation in the CWs. We studied, in an in vitro system, the interaction of SiO2 with the peroxidase-catalyzed polymerization of a lignin monomer into the lignin model compound, imitating conditions of the last step of lignin formation. FTIR and fluorescence spectroscopy and microscopy showed that Si is bound to the final polymer, and the structure of the Si-DHP differs from pure DHP. Fluorescence spectroscopy showed that Si does not bind to the monomers, so Si probably inhibits the formation of the larger lignin fragments, as evidenced by HPLC-DAD, by binding to dimmers formed during DHP synthesis. The structural changes of the polymer are related to the changed proportion of the fractions of various MW. The enzyme catalyzing DHP synthesis was not inhibited by Si. HRP activity was increased in presence of Si except for 6 mM Si. This may indicate that the complex formed with Si and short oligomers activates the enzyme, and prevents the formation of the large fragments.
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Affiliation(s)
- Ksenija Radotić
- University of Belgrade, Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade.
| | - Daniela Đikanović
- University of Belgrade, Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade
| | - Aleksandar Kalauzi
- University of Belgrade, Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade
| | - Gordana Tanasijević
- University of Belgrade, Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade
| | - Vuk Maksimović
- University of Belgrade, Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade
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15
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Mizuta H, Uji T, Yasui H. Extracellular silicate uptake and deposition induced by oxidative burst in Saccharina japonica sporophytes (Phaeophyceae). ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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16
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Dhiman P, Rajora N, Bhardwaj S, Sudhakaran SS, Kumar A, Raturi G, Chakraborty K, Gupta OP, Devanna BN, Tripathi DK, Deshmukh R. Fascinating role of silicon to combat salinity stress in plants: An updated overview. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 162:110-123. [PMID: 33667964 DOI: 10.1016/j.plaphy.2021.02.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/07/2021] [Indexed: 05/04/2023]
Abstract
Salt stress limits plant growth and productivity by severely impacting the fundamental physiological processes. Silicon (Si) supplementation is considered one of the promising methods to improve plant resilience under salt stress. Here, the role of Si in modulating physiological and biochemical processes that get adversely affected by high salinity, is discussed. Although numerous reports show the beneficial effects of Si under stress, the precise molecular mechanism underlying this is not well understood. Questions like whether all plants are equally benefitted with Si supplementation despite having varying Si uptake capability and salinity tolerance are still elusive. This review illustrates the Si uptake and accumulation mechanism to understand the direct or indirect participation of Si in different physiological processes. Evaluation of plant responses at transcriptomics and proteomics levels are promising in understanding the role of Si. Integration of physiological understanding with omics scale information highlighted Si supplementation affecting the phytohormonal and antioxidant responses under salinity as a key factor defining improved resilience. Similarly, the crosstalk of Si with lignin and phenolic content under salt stress also seems to be an important phenomenon helping plants to reduce the stress. The present review also addressed various crucial mechanisms by which Si application alleviates salt stress, such as a decrease in oxidative damage, decreased lipid peroxidation, improved photosynthetic ability, and ion homeostasis. Besides, the application and challenges of using Si-nanoparticles have also been addressed. Comprehensive information and discussion provided here will be helpful to better understand the role of Si under salt stress.
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Affiliation(s)
- Pallavi Dhiman
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India; Department of Biotechnology Panjab University, Chandigarh, India
| | - Nitika Rajora
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India
| | - Shubham Bhardwaj
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Sreeja S Sudhakaran
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India; Department of Biotechnology Panjab University, Chandigarh, India
| | - Amit Kumar
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India
| | - Gaurav Raturi
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India; Department of Biotechnology Panjab University, Chandigarh, India
| | | | - Om Prakash Gupta
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India
| | - B N Devanna
- ICAR-National Rice Research Institute, Cuttack, Odisha, India
| | - Durgesh Kumar Tripathi
- Amity Institute of Organic Agriculture (AIOA), Amity University Uttar Pradesh, Noida, India
| | - Rupesh Deshmukh
- National Agri-Food Biotechnology Institute (NABI) Mohali, Punjab, India.
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17
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Myrans H, Vandegeer RK, Henry RJ, Gleadow RM. Nitrogen availability and allocation in sorghum and its wild relatives: Divergent roles for cyanogenic glucosides. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153393. [PMID: 33667954 DOI: 10.1016/j.jplph.2021.153393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Crop plants are assumed to have become more susceptible to pests as a result of selection for high growth rates during the process of domestication, consistent with resource allocation theories. We compared the investment by domesticated sorghum into cyanogenic glucosides, nitrogen-based specialised metabolites that break down to release hydrogen cyanide, with five wild relatives native to Australia. Plants were grown in pots in a greenhouse and supplied with low and high concentrations of nitrogen and monitored for 9 weeks. The concentrations of nitrate, total phenolics and silicon were also measured. Domesticated Sorghum bicolor had the highest leaf and root cyanogenic glucoside concentrations, and among the lowest nitrate and silicon concentrations under both treatments. Despite partitioning a much higher proportion of its stored nitrogen to cyanogenic glucosides than the wild species, S. bicolor's nitrogen productivity levels were among the highest. Most of the wild sorghums had higher concentrations of silicon and phenolics, which may provide an alternative defence system. Cyanogenic glucosides appear to be integral to S. bicolor's physiology, having roles in both growth and defence. Sorghum macrospermum displayed consistently low cyanogenic glucoside concentrations, high growth rates and high nitrogen productivity and represents a particularly attractive genetic resource for sorghum improvement.
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Affiliation(s)
- Harry Myrans
- School of Biological Sciences, Monash University, Wellington Rd, Clayton, VIC 3800, Australia
| | - Rebecca K Vandegeer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Robert J Henry
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Roslyn M Gleadow
- School of Biological Sciences, Monash University, Wellington Rd, Clayton, VIC 3800, Australia; Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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18
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Bathoova M, Švubová R, Bokor B, Neděla V, Tihlaříková E, Martinka M. Silicon triggers sorghum root enzyme activities and inhibits the root cell colonization by Alternaria alternata. PLANTA 2021; 253:29. [PMID: 33423117 DOI: 10.1007/s00425-020-03560-6] [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: 07/10/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Silicon inhibits the growth of Alternaria alternata into sorghum root cells by maintaining their integrity through stimulating biochemical defense reactions rather than by silica-based physical barrier creation. Although the ameliorating effect of silicon (Si) on plant resistance against fungal pathogens has been proven, the mechanism of its action needs to be better understood on a cellular level. The present study explores the effect of Si application in sorghum roots infected with fungus Alternaria alternata under controlled in vitro conditions. Detailed anatomical and cytological observations by both fluorescent and electron microscopy revealed that Si supplementation results in the inhibition of fungal hyphae growth into the protoplast of root cells. An approach of environmental scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy enabling spatial detection of Si even at low concentrations showed that there is no continual solid layer of silica in the root cell walls of the rhizodermis, mesodermis and exodermis physically blocking the fungal growth into the protoplasts. Additionally, biochemical evidence suggests that Si speeds up the onset of activities of phenylpropanoid pathway enzymes phenylalanine ammonia lyase, peroxidases and polyphenol oxidases involved in phenolic compounds production and deposition to plant cell walls. In conclusion, Si alleviates the negative impact of A. alternata infection by limiting hyphae penetration through sorghum root cell walls into protoplasts, thus maintaining their structural and functional integrity. This might occur by triggering plant biochemical defense responses rather than by creating compact Si layer deposits.
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Affiliation(s)
- Monika Bathoova
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic.
| | - Renáta Švubová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
| | - Boris Bokor
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
- Comenius University Science Park, Comenius University in Bratislava, Ilkovicova 8, 841 04, Bratislava, Slovak Republic
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 00, Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 00, Brno, Czech Republic
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
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19
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Zexer N, Elbaum R. Unique lignin modifications pattern the nucleation of silica in sorghum endodermis. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6818-6829. [PMID: 32154874 PMCID: PMC7709913 DOI: 10.1093/jxb/eraa127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/06/2020] [Indexed: 05/04/2023]
Abstract
Silicon dioxide in the form of hydrated silica is a component of plant tissues that can constitute several percent by dry weight in certain taxa. Nonetheless, the mechanism of plant silica formation is mostly unknown. Silicon (Si) is taken up from the soil by roots in the form of monosilicic acid molecules. The silicic acid is carried in the xylem and subsequently polymerizes in target sites to silica. In roots of sorghum (Sorghum bicolor), silica aggregates form in an orderly pattern along the inner tangential cell walls of endodermis cells. Using Raman microspectroscopy, autofluorescence, and scanning electron microscopy, we investigated the structure and composition of developing aggregates in roots of sorghum seedlings. Putative silica aggregation loci were identified in roots grown under Si starvation. These micrometer-scale spots were constructed of tightly packed modified lignin, and nucleated trace concentrations of silicic acid. Substantial variation in cell wall autofluorescence between Si+ and Si- roots demonstrated the impact of Si on cell wall chemistry. We propose that in Si- roots, the modified lignin cross-linked into the cell wall and lost its ability to nucleate silica. In Si+ roots, silica polymerized on the modified lignin and altered its structure. Our work demonstrates a high degree of control over lignin and silica deposition in cell walls.
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Affiliation(s)
- Nerya Zexer
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
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20
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Kumar S, Adiram-Filiba N, Blum S, Sanchez-Lopez JA, Tzfadia O, Omid A, Volpin H, Heifetz Y, Goobes G, Elbaum R. Siliplant1 protein precipitates silica in sorghum silica cells. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6830-6843. [PMID: 32485738 DOI: 10.1093/jxb/eraa258] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/26/2020] [Indexed: 05/26/2023]
Abstract
Silicon is absorbed by plant roots as silicic acid. The acid moves with the transpiration stream to the shoot, and mineralizes as silica. In grasses, leaf epidermal cells called silica cells deposit silica in most of their volume using an unknown biological factor. Using bioinformatics tools, we identified a previously uncharacterized protein in Sorghum bicolor, which we named Siliplant1 (Slp1). Slp1 is a basic protein with seven repeat units rich in proline, lysine, and glutamic acid. We found Slp1 RNA in sorghum immature leaf and immature inflorescence. In leaves, transcription was highest just before the active silicification zone (ASZ). There, Slp1 was localized specifically to developing silica cells, packed inside vesicles and scattered throughout the cytoplasm or near the cell boundary. These vesicles fused with the membrane, releasing their content in the apoplastic space. A short peptide that is repeated five times in Slp1 precipitated silica in vitro at a biologically relevant silicic acid concentration. Transient overexpression of Slp1 in sorghum resulted in ectopic silica deposition in all leaf epidermal cell types. Our results show that Slp1 precipitates silica in sorghum silica cells.
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Affiliation(s)
- Santosh Kumar
- Robert H Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | | | - Shula Blum
- Robert H Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Javier Arturo Sanchez-Lopez
- Department of Entomology, Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Oren Tzfadia
- Bioinformatics and Systems Biology, VIB/Ghent University, Gent, Belgium
| | - Ayelet Omid
- Danziger Innovations Limited, Mishmar Hashiva, Israel
| | - Hanne Volpin
- Danziger Innovations Limited, Mishmar Hashiva, Israel
| | - Yael Heifetz
- Department of Entomology, Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Gil Goobes
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
| | - Rivka Elbaum
- Robert H Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
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Tripathi DK, Singh VP, Lux A, Vaculik M. Silicon in plant biology: from past to present, and future challenges. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6699-6702. [PMID: 33264414 DOI: 10.1093/jxb/eraa448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
| | - Vijay Pratap Singh
- Department of Botany, C.M.P. Degree College, A Constituent Post Graduate College of University of Allahabad, Allahabad, India
| | - Alexander Lux
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Marek Vaculik
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia
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Sheng H, Chen S. Plant silicon-cell wall complexes: Identification, model of covalent bond formation and biofunction. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:13-19. [PMID: 32736240 DOI: 10.1016/j.plaphy.2020.07.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 05/10/2023]
Abstract
Silicon (Si) is the second most abundant element on earth crust, consisting primarily of silicate minerals. Si is found in the tissues of almost all terrestrial plants and is mostly deposited in specialized cells or cell walls as amorphous silica. Numerous discoveries have shown that in addition to non-covalent interactions through amorphous silica, Si can form covalent bonds with plant cell wall components such as hemicelluloses, pectin and lignin. The covalent bonds may be formed via Si-O-C linkages between monosilicic acid (H4SiO4) and cis-diols of cell wall polysaccharides or lignin. The covalently bound organosilicon, independent of amorphous inorganic silica, may play a crucial role in plant cell wall structure and remodeling and thus plant growth and its resistance against biotic and abiotic stresses. This review discusses the existing research on the discovery of plant silicon-cell wall complexes and proposes a model of their covalent bond formation and biofunction.
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Affiliation(s)
- Huachun Sheng
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
| | - Shaolin Chen
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
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23
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Lux A, Lukačová Z, Vaculík M, Švubová R, Kohanová J, Soukup M, Martinka M, Bokor B. Silicification of Root Tissues. PLANTS (BASEL, SWITZERLAND) 2020; 9:E111. [PMID: 31952260 PMCID: PMC7020167 DOI: 10.3390/plants9010111] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 01/05/2023]
Abstract
Silicon (Si) is not considered an essential element, however, its tissue concentration can exceed that of many essential elements in several evolutionary distant plant species. Roots take up Si using Si transporters and then translocate it to aboveground organs. In some plant species, root tissues are also places where a high accumulation of Si can be found. Three basic modes of Si deposition in roots have been identified so far: (1) impregnation of endodermal cell walls (e.g., in cereals, such as Triticum (wheat)); (2) formation of Si-aggregates associated with endodermal cell walls (in the Andropogoneae family, which includes Sorghum and Saccharum (sugarcane)); (3) formation of Si aggregates in "stegmata" cells, which form a sheath around sclerenchyma fibers e.g., in some palm species (Phoenix (date palm)). In addition to these three major and most studied modes of Si deposition in roots, there are also less-known locations, such as deposits in xylem cells and intercellular deposits. In our research, the ontogenesis of individual root cells that accumulate Si is discussed. The documented and expected roles of Si deposition in the root is outlined mostly as a reaction of plants to abiotic and biotic stresses.
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Affiliation(s)
- Alexander Lux
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
- Institute of Chemistry, Slovak Academy of Sciences, 845 36 Bratislava, Slovakia
| | - Zuzana Lukačová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
| | - Marek Vaculík
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, 845 23 Bratislava, Slovakia
| | - Renáta Švubová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
| | - Jana Kohanová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
| | - Milan Soukup
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
- Institute of Chemistry, Slovak Academy of Sciences, 845 36 Bratislava, Slovakia
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
| | - Boris Bokor
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; (A.L.); (Z.L.); (M.V.); (R.Š.); (J.K.); (M.S.); (M.M.)
- Comenius University Science Park, 841 04 Bratislava, Slovakia
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Zancajo VMR, Diehn S, Filiba N, Goobes G, Kneipp J, Elbaum R. Spectroscopic Discrimination of Sorghum Silica Phytoliths. FRONTIERS IN PLANT SCIENCE 2019; 10:1571. [PMID: 31921236 PMCID: PMC6917640 DOI: 10.3389/fpls.2019.01571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 11/11/2019] [Indexed: 05/09/2023]
Abstract
Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work, we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis, we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types.
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Affiliation(s)
- Victor M. R. Zancajo
- School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Berlin, Germany
- Chemistry Department, Humboldt-Universität zu Berlin, Berlin, Germany
- BAM Federal Institute for Materials Research and Testing, Berlin, Germany
- *Correspondence: Victor M. R. Zancajo, ; Janina Kneipp, ; Rivka Elbaum,
| | - Sabrina Diehn
- Chemistry Department, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nurit Filiba
- Department of Chemistry, Bar Ilan University, Ramat Gan, Israel
| | - Gil Goobes
- Department of Chemistry, Bar Ilan University, Ramat Gan, Israel
| | - Janina Kneipp
- School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Berlin, Germany
- Chemistry Department, Humboldt-Universität zu Berlin, Berlin, Germany
- BAM Federal Institute for Materials Research and Testing, Berlin, Germany
- *Correspondence: Victor M. R. Zancajo, ; Janina Kneipp, ; Rivka Elbaum,
| | - Rivka Elbaum
- R. H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
- *Correspondence: Victor M. R. Zancajo, ; Janina Kneipp, ; Rivka Elbaum,
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