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Holden CA, McAinsh MR, Taylor JE, Beckett P, Albacete A, Martínez-Andújar C, Morais CLM, Martin FL. Attenuated total reflection Fourier-transform infrared spectroscopy for the prediction of hormone concentrations in plants. Analyst 2024. [PMID: 38712606 DOI: 10.1039/d3an01817b] [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
Plant hormones are important in the control of physiological and developmental processes including seed germination, senescence, flowering, stomatal aperture, and ultimately the overall growth and yield of plants. Many currently available methods to quantify such growth regulators quickly and accurately require extensive sample purification using complex analytic techniques. Herein we used ultra-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) to create and validate the prediction of hormone concentrations made using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectral profiles of both freeze-dried ground leaf tissue and extracted xylem sap of Japanese knotweed (Reynoutria japonica) plants grown under different environmental conditions. In addition to these predictions made with partial least squares regression, further analysis of spectral data was performed using chemometric techniques, including principal component analysis, linear discriminant analysis, and support vector machines (SVM). Plants grown in different environments had sufficiently different biochemical profiles, including plant hormonal compounds, to allow successful differentiation by ATR-FTIR spectroscopy coupled with SVM. ATR-FTIR spectral biomarkers highlighted a range of biomolecules responsible for the differing spectral signatures between growth environments, such as triacylglycerol, proteins and amino acids, tannins, pectin, polysaccharides such as starch and cellulose, DNA and RNA. Using partial least squares regression, we show the potential for accurate prediction of plant hormone concentrations from ATR-FTIR spectral profiles, calibrated with hormonal data quantified by UHPLC-HRMS. The application of ATR-FTIR spectroscopy and chemometrics offers accurate prediction of hormone concentrations in plant samples, with advantages over existing approaches.
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Affiliation(s)
- Claire A Holden
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Martin R McAinsh
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Jane E Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | | | - Alfonso Albacete
- Institute for Agro-Environmental Research and Development of Murcia (IMIDA), Department of Plant Production and Agrotechnology, C/ Mayor s/n, La Alberca, E-30150 Murcia, Spain
- CEBAS-CSIC, Department of Plant Nutrition, Campus Universitario de Espinardo, E-30100 Murcia, Spain
| | | | - Camilo L M Morais
- Center for Education, Science and Technology of the Inhamuns Region, State University of Ceará, Tauá 63660-000, Brazil
- Graduate Program in Chemistry, Institute of Chemistry, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil
| | - Francis L Martin
- Department of Cellular Pathology, Blackpool Teaching Hospitals NHS Foundation Trust, Whinney Heys Road, Blackpool FY3 8NR, UK.
- Biocel UK Ltd, Hull HU10 6TS, UK
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2
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Yang Q, Deng X, Liu T, Qian J, Zhang P, Zhu E, Wang J, Zhu X, Kudoyarova G, Zhao J, Zhang K. Abscisic acid root-to-shoot translocation by transporter AtABCG25 mediates stomatal movements in Arabidopsis. PLANT PHYSIOLOGY 2024; 195:671-684. [PMID: 38345859 DOI: 10.1093/plphys/kiae073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/05/2024] [Indexed: 05/02/2024]
Abstract
The phytohormone abscisic acid (ABA) plays a central role in regulating stomatal movements under drought conditions. The root-derived peptide CLAVATA3/EMBRYO SURROUNDING REGION-RELATED 25 (CLE25) moves from the root to shoot for activating ABA biosynthesis under drought conditions. However, the root-to-shoot translocation of root-derived ABA and its regulation of stomatal movements in the shoot remain to be clarified. Here, we reveal that the ABA transporter ATP-binding cassette subfamily G member 25 (AtABCG25) mediates root-to-shoot translocation of ABA and ABA-glucosyl ester (ABA-GE) in Arabidopsis (Arabidopsis thaliana). Isotope-labeled ABA tracer experiments and hormone quantification in xylem sap showed that the root-to-shoot translocation of ABA and ABA-GE was substantially impaired in the atabcg25 mutant under nondrought and drought conditions. However, the contents of ABA and ABA-GE in the leaves were lower in the atabcg25 mutant than in the wild type (WT) under nondrought but similar under drought conditions. Consistently, the stomatal closure was suppressed in the atabcg25 mutant under nondrought but not under drought conditions. The transporter activity assays showed that AtABCG25 directly exported ABA and ABA-GE in planta and in yeast (Saccharomyces cerevisiae) cells. Thus, we proposed a working model in which root-derived ABA transported by AtABCG25 via xylem mediates stomatal movements in the shoot under nondrought conditions but might exhibit little effect on stomatal movements under drought conditions. These findings extend the functions of AtABCG25 and provide insights into the long-distance translocation of ABA and its role in stomatal movements.
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Affiliation(s)
- Qin Yang
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Xiaojuan Deng
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Ting Liu
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Jiayun Qian
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Penghong Zhang
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Engao Zhu
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Jingqi Wang
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Xiaoxian Zhu
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Guzel Kudoyarova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya 69, Ufa 450054, Russia
| | - Jiangzhe Zhao
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
| | - Kewei Zhang
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China
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Castro-Valdecantos P, Puértolas J, Dodd IC. Similar soil drying-induced stomatal closure in soybean genotypes varying in abscisic acid accumulation and stomatal sensitivity to abscisic acid. FUNCTIONAL PLANT BIOLOGY : FPB 2024; 51:NULL. [PMID: 37072870 DOI: 10.1071/fp23012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/21/2023] [Indexed: 05/03/2023]
Abstract
Different soybean cultivars (Williams 82 , Union , Jindou 21 , Long Huang 1 , Long Huang 2 ) were exposed to drying soil, to investigate whether endogenous abscisic acid (ABA) concentrations and leaf water relations regulated stomatal behaviour. We measured ABA concentrations in xylem and tissue of the first and second trifoliate leaves respectively; stomatal conductance (gs ) and leaf water potential (Ψleaf ) in both leaves; and water content in soil. Cultivar variation in leaf area and g s caused different rates of soil drying, but g s and Ψ leaf declined similarly with soil drying in all cultivars. Variation in leaf xylem ABA concentration better explained stomatal responses than foliar ABA concentration in some cultivars, and was highly correlated with stomatal conductance. Xylem ABA concentration in well-watered soil was highest in Union , and in drying soil was lowest in Jindou 21 and Long Huang 2 , although the latter had the highest foliar ABA concentrations. Jindou 21 accumulated lower xylem ABA concentrations than other cultivars as soil moisture or Ψ leaf decreased, but its stomatal sensitivity to xylem ABA was greater. Because cultivars varied in both ABA accumulation and stomatal sensitivity to ABA, but had similar stomatal sensitivity to Ψ leaf , leaf water relations seem more important in regulating stomatal closure of soybean.
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Affiliation(s)
- Pedro Castro-Valdecantos
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and School of Life Sciences and Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Sha Tin, Hong Kong, China; and The Joint Institute for the Environmental Research and Education, Guangzhou, China; and Present address: Department of Agronomy, Escuela Técnica Superior de Ingeniería Agronómica, University of Seville, Ctra. Utrera km. 1, Seville 41013, Spain
| | - Jaime Puértolas
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and Present address: Department of Botany and Plant Ecology and Physiology, University of La Laguna, Facultad de Farmacia, Avd Astrofísico Francisco Sánchez s/n, San Cristóbal de La Laguna, Canary Islands 38200, Spain
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and The Joint Institute for the Environmental Research and Education, Guangzhou, China
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Biopriming of Maize Seeds with a Novel Bacterial Strain SH-6 to Enhance Drought Tolerance in South Korea. PLANTS 2022; 11:plants11131674. [PMID: 35807630 PMCID: PMC9268940 DOI: 10.3390/plants11131674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 01/23/2023]
Abstract
Maize is the third most common cereal crop worldwide, after rice and wheat, and plays a vital role in preventing global hunger crises. Approximately 50% of global crop yields are reduced by drought stress. Bacteria as biostimulants for biopriming can improve yield and enhance sustainable food production. Further, seed biopriming stimulates plant defense mechanisms. In this study, we isolated bacteria from the rhizosphere of Artemisia plants from Pohang beach, Daegu, South Korea. Twenty-three isolates were isolated and screened for growth promoting potential. Among them, bacterial isolate SH-6 was selected based on maximum induced tolerance to polyethylene glycol-simulated drought. SH-6 showed ABA concentration = 1.06 ± 0.04 ng/mL, phosphate solubilizing index = 3.7, and sucrose concentration = 0.51 ± 0.13 mg/mL. The novel isolate SH-6 markedly enhanced maize seedling tolerance to oxidative stress owing to the presence of superoxide dismutase, catalase, and ascorbate peroxidase activities in the culture media. Additionally, we quantified and standardized the biopriming effect of SH-6 on maize seeds. SH-6 significantly increased maize seedling drought tolerance by up to 20%, resulting in 80% germination potential. We concluded that the novel bacterium isolate SH-6 (gene accession number (OM757882) is a biostimulant that can improve germination performance under drought stress.
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Ludwig-Müller J, Rattunde R, Rößler S, Liedel K, Benade F, Rost A, Becker J. Two Auxinic Herbicides Affect Brassica napus Plant Hormone Levels and Induce Molecular Changes in Transcription. Biomolecules 2021; 11:biom11081153. [PMID: 34439819 PMCID: PMC8391463 DOI: 10.3390/biom11081153] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 11/16/2022] Open
Abstract
With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2–168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.
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Affiliation(s)
- Jutta Ludwig-Müller
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany; (R.R.); (S.R.); (K.L.); (F.B.)
- Correspondence:
| | - Roman Rattunde
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany; (R.R.); (S.R.); (K.L.); (F.B.)
| | - Sabine Rößler
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany; (R.R.); (S.R.); (K.L.); (F.B.)
| | - Katja Liedel
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany; (R.R.); (S.R.); (K.L.); (F.B.)
| | - Freia Benade
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany; (R.R.); (S.R.); (K.L.); (F.B.)
| | - Agnes Rost
- Corteva Agriscience Germany GmbH, Riedenburger Str. 7, 81677 München, Germany; (A.R.); (J.B.)
| | - Jörg Becker
- Corteva Agriscience Germany GmbH, Riedenburger Str. 7, 81677 München, Germany; (A.R.); (J.B.)
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Innes SN, Solhaug KA, Torre S, Dodd IC. Different abscisic acid-deficient mutants show unique morphological and hydraulic responses to high air humidity. PHYSIOLOGIA PLANTARUM 2021; 172:1795-1807. [PMID: 33826767 DOI: 10.1111/ppl.13417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/09/2021] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
High relative humidity (RH) perturbs plant growth, stomatal functioning and abscisic acid (ABA) homeostasis, but the role of ABA in this physiological regulation is equivocal. To determine the role(s) of ABA in plant responses to high RH, wild-type (WT) tomato and barley plants and their respective ABA-deficient mutants flacca and Az34 (which are mutated in the same locus of the ABA biosynthesis pathway) were grown in contrasting RHs (60% and 90%) to measure biomass partitioning, stomatal traits and water relations. Surprisingly, growth RH did not affect foliar ABA levels in either species. While Az34 showed similar stomatal size and density as WT plants, flacca had larger and more abundant stomata. High RH increased stomatal size in tomato, but decreased it in barley, and decreased stomatal density in tomato, but not in barley. Altered stomatal responses in ABA-deficient plants to high RH had little effect on tomato photosynthesis, but Az34 barley showed lower photosynthesis. ABA deficiency decreased relative shoot growth rate (RGRSHOOT ) in both species, yet this was counteracted by high RH increasing leaf water status in tomato, but not in barley. High RH increased RGRSHOOT in flacca, but not in WT tomatoes, while having no effect on RGRSHOOT in barley, but affecting barley net assimilation rate, leaf area ratio (LAR) and specific leaf area in an ABA-dependent manner. ABA-RH interaction affected leaf development in tomato only. Thus, different crop species show variable responses to both high RH and ABA deficiency, making it difficult to generalise on the role of ABA in growth regulation at contrasting RHs.
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Affiliation(s)
- Sheona N Innes
- Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Knut Asbjørn Solhaug
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Sissel Torre
- Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
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7
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Romero-Aranda MR, González-Fernández P, Pérez-Tienda JR, López-Diaz MR, Espinosa J, Granum E, Traverso JÁ, Pineda B, Garcia-Sogo B, Moreno V, Asins MJ, Belver A. Na + transporter HKT1;2 reduces flower Na + content and considerably mitigates the decline in tomato fruit yields under saline conditions. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 154:341-352. [PMID: 32604062 DOI: 10.1016/j.plaphy.2020.05.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/29/2020] [Accepted: 05/10/2020] [Indexed: 06/11/2023]
Abstract
Genes encoding HKT1-like Na+ transporters play a key role in the salinity tolerance mechanism in Arabidopsis and other plant species by retrieving Na+ from the xylem of different organs and tissues. In this study, we investigated the role of two HKT1;2 allelic variants in tomato salt tolerance in relation to vegetative growth and fruit yield in plants subjected to salt treatment in a commercial greenhouse under real production conditions. We used two near-isogenic lines (NILs), homozygous for either the Solanum lycopersicum (NIL17) or S. cheesmaniae (NIL14) allele, at HKT1;2 loci and their respective RNAi-Sl/ScHKT1;2 lines. The results obtained show that both ScHKT1;2- and SlHKT1;2-silenced lines display hypersensitivity to salinity associated with an altered leaf Na+/K+ ratio, thus confirming that HKT1;2 plays an important role in Na+ homeostasis and salinity tolerance in tomato. Both silenced lines also showed Na+ over-accumulation and a slight, but significant, reduction in K+ content in the flower tissues of salt-treated plants and consequently a higher Na+/K+ ratio as compared to the respective unsilenced lines. This altered Na+/K+ ratio in flower tissues is associated with a sharp reduction in fruit yield, measured as total fresh weight and number of fruits, in both silenced lines under salinity conditions. Our findings demonstrate that Na+ transporter HKT1;2 protects the flower against Na+ toxicity and mitigates the reduction in tomato fruit yield under salinity conditions.
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Affiliation(s)
- María Remedios Romero-Aranda
- Department of Plant Breeding and Biotechnology, La Mayora Institute for Mediterranean and Subtropical Horticulture, UMA/CSIC, Malaga, Spain
| | - Paloma González-Fernández
- Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/ Prof. Albareda 1, 18008, Granada, Spain
| | - Jacob Rafael Pérez-Tienda
- Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/ Prof. Albareda 1, 18008, Granada, Spain
| | - María Remedios López-Diaz
- Department of Plant Breeding and Biotechnology, La Mayora Institute for Mediterranean and Subtropical Horticulture, UMA/CSIC, Malaga, Spain
| | - Jesús Espinosa
- Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/ Prof. Albareda 1, 18008, Granada, Spain
| | - Espen Granum
- Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/ Prof. Albareda 1, 18008, Granada, Spain
| | - Jose Ángel Traverso
- Department of Cellular Biology, Faculty of Sciences, University of Granada, 18071, Granada, Spain
| | - Benito Pineda
- Laboratory of Tissue Culture and Plant Breeding, Institute of Plant Molecular and Cellular Biology, Polytechnic University of Valencia-CSIC, Valencia, 46022, Spain
| | - Begoña Garcia-Sogo
- Laboratory of Tissue Culture and Plant Breeding, Institute of Plant Molecular and Cellular Biology, Polytechnic University of Valencia-CSIC, Valencia, 46022, Spain
| | - Vicente Moreno
- Laboratory of Tissue Culture and Plant Breeding, Institute of Plant Molecular and Cellular Biology, Polytechnic University of Valencia-CSIC, Valencia, 46022, Spain
| | - María José Asins
- Plant Protection and Biotechnology Center, Valencian Institute of Agrarian Research (IVIA), 46113, Moncada, Valencia, Spain
| | - Andrés Belver
- Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/ Prof. Albareda 1, 18008, Granada, Spain.
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Samarah LZ, Tran TH, Stacey G, Vertes A. In Vivo Chemical Analysis of Plant Sap from the Xylem and Single Parenchymal Cells by Capillary Microsampling Electrospray Ionization Mass Spectrometry. Anal Chem 2020; 92:7299-7306. [PMID: 32343130 DOI: 10.1021/acs.analchem.0c00939] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In plants, long-distance transport of chemicals from source to sink takes place through the transfer of sap inside complex trafficking systems. Access to this information provides insight into the physiological responses that result from the interactions between the organism and its environment. In vivo analysis offers minimal perturbation to the physiology of the organism, thus providing information that represents the native physiological state more accurately. Here we describe capillary microsampling with electrospray ionization mass spectrometry (ESI-MS) for the in vivo analysis of xylem sap directly from plants. Initially, fast MS profiling was performed by ESI from the whole sap exuding from wounds of living plants in their native environment. This sap, however, originated from the xylem and phloem and included the cytosol of damaged cells. Combining capillary microsampling with ESI-MS enabled targeted sampling of the xylem sap and single parenchymal cells in the pith, thereby differentiating their chemical compositions. With this method we analyzed soybean plants infected by nitrogen-fixing bacteria and uninfected plants to investigate the effects of symbiosis on chemical transport through the sap. Infected plants exhibited higher abundances for certain nitrogen-containing metabolites in their sap, namely allantoin, allantoic acid, hydroxymethylglutamate, and methylene glutamate, compared to uninfected plants. Using capillary microsampling, we localized these compounds to the xylem, which indicated their transport from the roots to the upper parts of the plant. Differences between metabolite levels in sap from the infected and uninfected plants indicated that the transport of nitrogen-containing and other metabolites is regulated depending on the source of nitrogen supply.
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Affiliation(s)
- Laith Z Samarah
- Department of Chemistry, George Washington University, Washington, DC 20052, United States
| | - Tina H Tran
- Department of Chemistry, George Washington University, Washington, DC 20052, United States
| | - Gary Stacey
- Divisions of Plant Sciences and Biochemistry, C. S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Akos Vertes
- Department of Chemistry, George Washington University, Washington, DC 20052, United States
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Longchar B, Phukan T, Yadav S, Senthil‐Kumar M. An efficient low-cost xylem sap isolation method for bacterial wilt assays in tomato. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11335. [PMID: 32351796 PMCID: PMC7186903 DOI: 10.1002/aps3.11335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 02/12/2020] [Indexed: 06/01/2023]
Abstract
PREMISE A portable, simple, yet efficient method was developed for the rapid extraction of xylem sap from the stems and petioles of tomato plants for diagnostic and quantification assays of the xylem-colonizing wilt bacterium Ralstonia solanacearum. METHODS AND RESULTS Xylem saps were extracted from tomato stem sections using negative pressure generated from handheld needleless syringes. The samples were collected from plants grown under different soil moisture levels at four days after inoculation with the pathogen. Pipette tips were modified to serve as adapters for the stem sections. The quantification of the bacterial load in the extracted sap was performed by plating sap dilutions in Kelman's triphenyltetrazolium chloride (TTC) medium. Pathogen identity was further confirmed by performing a PCR using R. solanacearum-specific primers. CONCLUSIONS Due to its simplicity, portability, and thoroughness of extraction from predetermined tissue sizes, the method can potentially facilitate high-throughput onsite sampling from a large number of samples in a short time, which cannot be achieved with other available techniques.
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Affiliation(s)
| | - Tarinee Phukan
- National Institute of Plant Genome Research, Aruna Asaf Ali MargNew Delhi110067India
| | - Sarita Yadav
- National Institute of Plant Genome Research, Aruna Asaf Ali MargNew Delhi110067India
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10
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Marino G, Haworth M, Scartazza A, Tognetti R, Centritto M. A Comparison of the Variable J and Carbon-Isotopic Composition of Sugars Methods to Assess Mesophyll Conductance from the Leaf to the Canopy Scale in Drought-Stressed Cherry. Int J Mol Sci 2020; 21:E1222. [PMID: 32059382 PMCID: PMC7072943 DOI: 10.3390/ijms21041222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 01/27/2023] Open
Abstract
Conductance of CO2 across the mesophyll (Gm) frequently constrains photosynthesis (PN) but cannot be measured directly. We examined Gm of cherry (Prunus avium L.) subjected to severe drought using the variable J method and carbon-isotopic composition (δ13C) of sugars from the centre of the leaf, the leaf petiole sap, and sap from the largest branch. Depending upon the location of the plant from which sugars are sampled, Gm may be estimated over scales ranging from a portion of the leaf to a canopy of leaves. Both the variable J and δ13C of sugars methods showed a reduction in Gm as soil water availability declined. The δ13C of sugars further from the source of their synthesis within the leaf did not correspond as closely to the diffusive and C-isotopic discrimination conditions reflected in the instantaneous measurement of gas exchange and chlorophyll-fluorescence utilised by the variable J approach. Post-photosynthetic fractionation processes and/or the release of sugars from stored carbohydrates (previously fixed under different environmental and C-isotopic discrimination conditions) may reduce the efficacy of the δ13C of sugars from leaf petiole and branch sap in estimating Gm in a short-term study. Consideration should be given to the spatial and temporal scales at which Gm is under observation in any experimental analysis.
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Affiliation(s)
- Giovanni Marino
- National Research Council of Italy - Institute of Sustainable Plant Protection (CNR - IPSP), Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy; (M.H.); (M.C.)
| | - Matthew Haworth
- National Research Council of Italy - Institute of Sustainable Plant Protection (CNR - IPSP), Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy; (M.H.); (M.C.)
| | - Andrea Scartazza
- National Research Council of Italy—Research Institute on Terrestrial Ecosystems (CNR–IRET), Via Moruzzi 1, 56124 Pisa, Italy;
| | - Roberto Tognetti
- Department of Agricultural, Environmental and Food Sciences - University of Molise, Via Francesco De Sanctis, 86100 Campobasso, Italy;
- The EFI Project Centre on Mountain Forests (MOUNTFOR), Edmund Mach Foundation, 38010 San Michele all’Adige (TN), Italy
| | - Mauro Centritto
- National Research Council of Italy - Institute of Sustainable Plant Protection (CNR - IPSP), Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy; (M.H.); (M.C.)
- CNR-Eni Research Center “Acqua”, Research Center Metapontum Agrobios, 750125 Metaponto, Italy
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Fang L, Abdelhakim LOA, Hegelund JN, Li S, Liu J, Peng X, Li X, Wei Z, Liu F. ABA-mediated regulation of leaf and root hydraulic conductance in tomato grown at elevated CO 2 is associated with altered gene expression of aquaporins. HORTICULTURE RESEARCH 2019; 6:104. [PMID: 31645959 PMCID: PMC6804533 DOI: 10.1038/s41438-019-0187-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/16/2019] [Accepted: 08/03/2019] [Indexed: 05/07/2023]
Abstract
Elevated CO2 concentration in the air (e[CO2]) decreases stomatal density (SD) and stomatal conductance (g s) where abscisic acid (ABA) may play a role, yet the underlying mechanism remains largely elusive. We investigated the effects of e[CO2] (800 ppm) on leaf gas exchange and water relations of two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (WT) and its ABA-deficient mutant (flacca). Compared to plants grown at ambient CO2 (400 ppm), e[CO2] stimulated photosynthetic rate in both genotypes, while depressed the g s only in WT. SD showed a similar response to e[CO2] as g s, although the change was not significant. e[CO2] increased leaf and xylem ABA concentrations and xylem sap pH, where the increases were larger in WT than in flacca. Although leaf water potential was unaffected by CO2 growth environment, e[CO2] lowered osmotic potential, hence tended to increase turgor pressure particularly for WT. e[CO2] reduced hydraulic conductance of leaf and root in WT but not in flacca, which was associated with downregulation of gene expression of aquaporins. It is concluded that ABA-mediated regulation of g s, SD, and gene expression of aquaporins coordinates the whole-plant hydraulics of tomato grown at different CO2 environments.
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Affiliation(s)
- Liang Fang
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
- Present Address: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Lamis Osama Anwar Abdelhakim
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
| | - Josefine Nymark Hegelund
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
| | - Shenglan Li
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
| | - Jie Liu
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
- Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, 712100 Yangling, Shaanxi China
| | - Xiaoying Peng
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
- College of Bioscience and Biotechnology, Hunan Agricultural University, 410128 Changsha, Hunan China
| | - Xiangnan Li
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102 Changchun, China
| | - Zhenhua Wei
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
- Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, 712100 Yangling, Shaanxi China
| | - Fulai Liu
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
- Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, 712100 Yangling, Shaanxi China
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12
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Li W, de Ollas C, Dodd IC. Long-distance ABA transport can mediate distal tissue responses by affecting local ABA concentrations. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:16-33. [PMID: 29052969 DOI: 10.1111/jipb.12605] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/16/2017] [Indexed: 05/21/2023]
Abstract
Environmental stresses that perturb plant water relations influence abscisic acid (ABA) concentrations, but it is unclear whether long-distance ABA transport contributes to changes in local ABA levels. To determine the physiological relevance of ABA transport, we made reciprocal- and self-grafts of ABA-deficient flacca mutant and wild-type (WT) tomato plants, in which low phosphorus (P) conditions decreased ABA concentrations while salinity increased ABA concentrations. Whereas foliar ABA concentrations in the WT scions were rootstock independent under conditions, salinity resulted in long-distance transport of ABA: flacca scions had approximately twice as much ABA when grafted on WT rootstocks compared to flacca rootstocks. Root ABA concentrations were scion dependent: both WT and flacca rootstocks had less ABA with the flacca mutant scion than with the WT scion under conditions. In WT scions, whereas rootstock genotype had limited effects on stomatal conductance under conditions, a flacca rootstock decreased leaf area of stressed plants, presumably due to attenuated root-to-shoot ABA transport. In flacca scions, a WT rootstock decreased stomatal conductance but increased leaf area of stressed plants, likely due to enhanced root-to-shoot ABA transport. Thus, long-distance ABA transport can affect responses in distal tissues by changing local ABA concentrations.
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Affiliation(s)
- Wenrao Li
- College of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Carlos de Ollas
- Plant & Crop Sciences, Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Ian C Dodd
- Plant & Crop Sciences, Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, United Kingdom
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13
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Saradadevi R, Palta JA, Siddique KHM. ABA-Mediated Stomatal Response in Regulating Water Use during the Development of Terminal Drought in Wheat. FRONTIERS IN PLANT SCIENCE 2017; 8:1251. [PMID: 28769957 PMCID: PMC5513975 DOI: 10.3389/fpls.2017.01251] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/03/2017] [Indexed: 05/19/2023]
Abstract
End-of-season drought or "terminal drought," which occurs after flowering, is considered the most significant abiotic stress affecting crop yields. Wheat crop production in Mediterranean-type environments is often exposed to terminal drought due to decreasing rainfall and rapid increases in temperature and evapotranspiration during spring when wheat crops enter the reproductive stage. Under such conditions, every millimeter of extra soil water extracted by the roots benefits grain filling and yield and improves water use efficiency (WUE). When terminal drought develops, soil dries from the top, exposing the top part of the root system to dry soil while the bottom part is in contact with available soil water. Plant roots sense the drying soil and produce signals, which on transmission to shoots trigger stomatal closure to regulate crop water use through transpiration. However, transpiration is linked to crop growth and productivity and limiting transpiration may reduce potential yield. While an early and high degree of stomatal closure affects photosynthesis and hence biomass production, a late and low degree of stomatal closure exhausts available soil water rapidly which results in yield losses through a reduction in post-anthesis water use. The plant hormone abscisic acid (ABA) is considered the major chemical signal involved in stomatal regulation. Wheat genotypes differ in their ability to produce ABA under drought and also in their stomatal sensitivity to ABA. In this viewpoint article we discuss the possibilities of exploiting genotypic differences in ABA response to soil drying in regulating the use of water under terminal drought. Root density distribution in the upper drying layers of the soil profile is identified as a candidate trait that can affect ABA accumulation and subsequent stomatal closure. We also examine whether leaf ABA can be designated as a surrogate characteristic for improved WUE in wheat to sustain grain yield under terminal drought. Ease of collecting leaf samples to quantify ABA compared to extracting xylem sap will facilitate rapid screening of a large number of germplasm for drought tolerance.
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Affiliation(s)
- Renu Saradadevi
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
| | - Jairo A. Palta
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
- CSIRO Agriculture and Food, WembleyWA, Australia
| | - Kadambot H. M. Siddique
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
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14
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Martínez-Andújar C, Ruiz-Lozano JM, Dodd IC, Albacete A, Pérez-Alfocea F. Hormonal and Nutritional Features in Contrasting Rootstock-mediated Tomato Growth under Low-phosphorus Nutrition. FRONTIERS IN PLANT SCIENCE 2017; 8:533. [PMID: 28443121 PMCID: PMC5386964 DOI: 10.3389/fpls.2017.00533] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/24/2017] [Indexed: 05/28/2023]
Abstract
Grafting provides a tool aimed to increase low-P stress tolerance of crops, however, little is known about the mechanism (s) by which rootstocks can confer resistance to P deprivation. In this study, 4 contrasting groups of rootstocks from different genetic backgrounds (Solanum lycopersicum var. cerasiforme and introgression and recombinant inbred lines derived from the wild relatives S. pennellii and S. pimpinellifolium) were grafted to a commercial F1 hybrid scion and cultivated under control (1 mM, c) and P deficient (0.1 mM, p) conditions for 30 days, to analyze rootstocks-mediated traits that impart low (L, low shoot dry weight, SDW) or high (H, high SDW) vigor. Xylem sap ionic and hormonal anlyses leaf nutritional status suggested that some physiological traits can explain rootstocks impacts on shoot growth. Although xylem P concentration increased with root biomass under both growing conditions, shoot biomass under low-P was explained by neither changes in root growth nor P transport and assimilation. Indeed, decreased root P export only explained the sensitivity of the HcLp rootstocks, while leaf P status was similarly affected in all graft combinations. Interestingly, most of the nutrients analyzed in the xylem sap correlated with root biomass under standard fertilization but only Ca was consistently related to shoot biomass under both control and low-P, suggesting an important role for this nutrient in rootstock-mediated vigor. Moreover, foliar Ca, S, and Mn concentrations were (i) specifically correlated with shoot growth under low-P and (ii) positively and negatively associated to the root-to-shoot transport of the cytokinin trans-zeatin (t-Z) and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), respectively. Indeed, those hormones seem to play an antagonistic positive (t-Z) and negative (ACC) role in the rootstock-mediated regulation of shoot growth in response to P nutrition. The use of Hp-type rootstocks seems to enhance P use efficiency of a commercial scion variety, therefore could potentially be used for increasing yield and agronomic stability under low P availability.
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Affiliation(s)
| | - Juan M. Ruiz-Lozano
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (CSIC)Granada, Spain
| | - Ian C. Dodd
- Lancaster Environment Centre, Lancaster UniversityLancaster, UK
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15
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Li W, Jia L, Wang L. Chemical signals and their regulations on the plant growth and water use efficiency of cotton seedlings under partial root-zone drying and different nitrogen applications. Saudi J Biol Sci 2017; 24:477-487. [PMID: 28386170 PMCID: PMC5372376 DOI: 10.1016/j.sjbs.2017.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/28/2016] [Accepted: 01/06/2017] [Indexed: 11/26/2022] Open
Abstract
Partial root-zone drying during irrigation (PRD) has been shown effective in enhancing plant water use efficiency (WUE), however, the roles of chemical signals from root and shoot that are involved and the possible interactions affected by nitrogen nutrition are not clear. Pot-grown cotton (Gossypium spp.) seedlings were treated with three levels of N fertilization and PRD. The concentrations of nitrate (NO3−), abscisic acid (ABA) and the pH value of leaf and root xylem saps, biomass and WUE were measured. Results showed that PRD plants produced larger biomass and higher WUE than non-PRD plants, with significant changes in leaf xylem ABA, leaf and root xylem NO3− concentrations and pH values, under heterogeneous soil moisture conditions. Simultaneously, high-N treated plants displayed larger changes in leaf xylem ABA and higher root xylem NO3− concentrations, than in the medium- or low-N treated plants. However, the WUE of plants in the low-N treatment was higher than that of those in the high- and medium-N treatments. PRD and nitrogen levels respectively induced signaling responses of ABA/NO3− and pH in leaf or root xylem to affect WUE and biomass under different watering levels, although significant interactions of PRD and nitrogen levels were found when these signal molecules responded to soil drying. We conclude that these signaling chemicals are regulated by interaction of PRD and nitrogen status to regulate stomatal behavior, either directly or indirectly, and thus increase PRD plant WUE under less irrigation.
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Affiliation(s)
- Wenrao Li
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, Henan 475004, China
| | - Liguo Jia
- College of Agronomy, Inner Mongolia Agricultural University, Huhhot 010019, China
| | - Lei Wang
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, Henan 475004, China
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16
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Martínez-Andújar C, Albacete A, Martínez-Pérez A, Pérez-Pérez JM, Asins MJ, Pérez-Alfocea F. Root-to-Shoot Hormonal Communication in Contrasting Rootstocks Suggests an Important Role for the Ethylene Precursor Aminocyclopropane-1-carboxylic Acid in Mediating Plant Growth under Low-Potassium Nutrition in Tomato. FRONTIERS IN PLANT SCIENCE 2016; 7:1782. [PMID: 27965690 PMCID: PMC5126091 DOI: 10.3389/fpls.2016.01782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/11/2016] [Indexed: 05/07/2023]
Abstract
Selection and breeding of rootstocks that can tolerate low K supply may increase crop productivity in low fertility soils and reduce fertilizer application. However, the underlying physiological traits are still largely unknown. In this study, 16 contrasting recombinant inbred lines (RILs) derived from a cross between domestic and wild tomato species (Solanum lycopersicum × Solanum pimpinellifolium) have been used to analyse traits related to the rootstock-mediated induction of low (L, low shoot fresh weight) or high (H, high shoot fresh weight) vigor to a commercial F1 hybrid grown under control (6 mM, c) and low-K (1 mM, k). Based on hormonal and ionomic composition in the root xylem sap and the leaf nutritional status after long-term (7 weeks) exposure low-K supply, a model can be proposed to explain the rootstocks effects on shoot performance with the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC) playing a pivotal negative role. The concentration of this hormone was higher in the low-vigor Lc and Lk rootstocks under both conditions, increased in the sensitive HcLk plants under low-K while it was reduced in the high-vigor Hk ones. Low ACC levels would promote the transport of K vs. Na in the vigorous Hk grafted plants. Along with K, Ca, and S, micronutrient uptake and transport were also activated in the tolerant Hk combinations under low-K. Additionally, an interconversion of trans-zeatin into trans-zeatin riboside would contribute to decrease ACC in the tolerant LcHk plants. The high vigor induced by the Hk plants can also be explained by an interaction of ACC with other hormones (cytokinins and salicylic, abscisic and jasmonic acids). Therefore, Hk rootstocks convert an elite tomato F1 cultivar into a (micro) nutrient-efficient phenotype, improving growth under reduced K fertilization.
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Affiliation(s)
| | - Alfonso Albacete
- Centro de Edafologia y Biologia Aplicada del Segura (CSIC)Murcia, Spain
| | | | | | - María José Asins
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Valencia, Spain
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17
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Minh Tran T, MacIntyre A, Khokhani D, Hawes M, Allen C. Extracellular DNases of Ralstonia solanacearum modulate biofilms and facilitate bacterial wilt virulence. Environ Microbiol 2016; 18:4103-4117. [PMID: 27387368 DOI: 10.1111/1462-2920.13446] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/01/2016] [Indexed: 12/21/2022]
Abstract
Ralstonia solanacearum is a soil-borne vascular pathogen that colonizes plant xylem vessels, a flowing, low-nutrient habitat where biofilms could be adaptive. Ralstonia solanacearum forms biofilm in vitro, but it was not known if the pathogen benefits from biofilms during infection. Scanning electron microscopy revealed that during tomato infection, R. solanacearum forms biofilm-like masses in xylem vessels. These aggregates contain bacteria embedded in a matrix including chromatin-like fibres commonly observed in other bacterial biofilms. Chemical and enzymatic assays demonstrated that the bacterium releases extracellular DNA in culture and that DNA is an integral component of the biofilm matrix. An R. solanacearum mutant lacking the pathogen's two extracellular nucleases (exDNases) formed non-spreading colonies and abnormally thick biofilms in vitro. The biofilms formed by the exDNase mutant in planta contained more and thicker fibres. This mutant was also reduced in virulence on tomato plants and did not spread in tomato stems as well as the wild-type strain, suggesting that these exDNases facilitate biofilm maturation and bacterial dispersal. To our knowledge, this is the first demonstration that R. solanacearum forms biofilms in plant xylem vessels, and the first documentation that plant pathogens use DNases to modulate their biofilm structure for systemic spread and virulence.
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Affiliation(s)
- Tuan Minh Tran
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - April MacIntyre
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Devanshi Khokhani
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Martha Hawes
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, 85721, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, 53706, USA
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18
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Boyle RKA, McAinsh M, Dodd IC. Stomatal closure of Pelargonium × hortorum in response to soil water deficit is associated with decreased leaf water potential only under rapid soil drying. PHYSIOLOGIA PLANTARUM 2016; 156:84-96. [PMID: 25974219 DOI: 10.1111/ppl.12346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 04/12/2015] [Indexed: 06/04/2023]
Abstract
Soil water deficits applied at different rates and for different durations can decrease both stomatal conductance (gs ) and leaf water potential (Ψleaf ). Understanding the physiological mechanisms regulating these responses is important in sustainable irrigation scheduling. Glasshouse-grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at various fractions of plant evapotranspiration (100, 75 and 50% ET) for 20 days or irrigation was withheld for 4 days. Xylem sap was collected and gs and Ψleaf were measured on days 15 and 20, and on days 16-19 for the respective treatments. Xylem sap pH and NO3 (-) and Ca(2+) concentrations did not differ between irrigation treatments. Xylem abscisic acid (ABA) concentrations ([ABA]xyl ) increased within 24 h of irrigation being withheld whilst gs and Ψleaf decreased. Supplying irrigation at a fraction of daily ET produced a similar relationship between [ABA]xyl and gs , but did not change Ψleaf . Treatment differences occurred independently of whether Ψleaf was measured in whole leaves with a pressure chamber, or in the lamina with a thermocouple psychrometer. Plants that were irrigated daily showed lower [ABA]xyl than plants from which irrigation was withheld, even at comparable soil moisture content. This implies that regular re-watering attenuates ABA signaling due to maintenance of soil moisture in the upper soil levels. Crucially, detached leaves supplied with synthetic ABA showed a similar relationship between [ABA]xyl and gs as intact plants, suggesting that stomatal closure of P. hortorum in response to soil water deficit is primarily an ABA-induced response, independent of changes in Ψleaf .
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Affiliation(s)
- Richard K A Boyle
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
| | - Martin McAinsh
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
| | - Ian C Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
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19
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Brychkova G, Yarmolinsky D, Batushansky A, Grishkevich V, Khozin-Goldberg I, Fait A, Amir R, Fluhr R, Sagi M. Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves. PLANTS 2015; 4:573-605. [PMID: 27135342 PMCID: PMC4844397 DOI: 10.3390/plants4030573] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 07/30/2015] [Accepted: 08/07/2015] [Indexed: 11/24/2022]
Abstract
Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S) metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA), Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA) cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants.
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Affiliation(s)
- Galina Brychkova
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Dmitry Yarmolinsky
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Albert Batushansky
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Vladislav Grishkevich
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Inna Khozin-Goldberg
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Aaron Fait
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Rachel Amir
- Migal-Galilee Technology Center, Southern Industrial Zone, POB831 Kiryat-Shmona 11016, Israel.
| | - Robert Fluhr
- Department of Plant Sciences, Weizmann Institute of Science, P.O.B. 26 Rehovot 76100, Israel.
| | - Moshe Sagi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
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20
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Dodd IC, Puértolas J, Huber K, Pérez-Pérez JG, Wright HR, Blackwell MSA. The importance of soil drying and re-wetting in crop phytohormonal and nutritional responses to deficit irrigation. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2239-52. [PMID: 25628330 PMCID: PMC4986717 DOI: 10.1093/jxb/eru532] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/05/2014] [Accepted: 12/10/2014] [Indexed: 05/11/2023]
Abstract
Soil drying and re-wetting (DRW) occurs at varying frequencies and intensities during crop production, and is deliberately used in water-saving irrigation techniques that aim to enhance crop water use efficiency. Soil drying not only limits root water uptake which can (but not always) perturb shoot water status, but also alters root synthesis of phytohormones and their transport to shoots to regulate leaf growth and gas exchange. Re-wetting the soil rapidly restores leaf water potential and leaf growth (minutes to hours), but gas exchange recovers more slowly (hours to days), probably mediated by sustained changes in root to shoot phytohormonal signalling. Partial rootzone drying (PRD) deliberately irrigates only part of the rootzone, while the remainder is allowed to dry. Alternating these wet and dry zones (thus re-wetting dry soil) substantially improves crop yields compared with maintaining fixed wet and dry zones or conventional deficit irrigation, and modifies phytohormonal (especially abscisic acid) signalling. Alternate wetting and drying (AWD) of rice can also improve yield compared with paddy culture, and is correlated with altered phytohormonal (including cytokinin) signalling. Both PRD and AWD can improve crop nutrition, and re-wetting dry soil provokes both physical and biological changes which affect soil nutrient availability. Whether this alters crop nutrient uptake depends on competition between plant and microbes for nutrients, with the rate of re-wetting determining microbial dynamics. Nevertheless, studies that examine the effects of soil DRW on both crop nutritional and phytohormonal responses are relatively rare; thus, determining the cause(s) of enhanced crop yields under AWD and PRD remains challenging.
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Affiliation(s)
- Ian C Dodd
- Centre for Sustainable Agriculture, Lancaster Environment Centre, Lancaster University, Lancaster LA1 1YQ, UK
| | - Jaime Puértolas
- Centre for Sustainable Agriculture, Lancaster Environment Centre, Lancaster University, Lancaster LA1 1YQ, UK
| | - Katrin Huber
- Institute of Bio- and Geosciences: Agrosphere (IBG 3), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | | | - Hannah R Wright
- Centre for Sustainable Agriculture, Lancaster Environment Centre, Lancaster University, Lancaster LA1 1YQ, UK
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21
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Pérez-Pérez JG, Dodd IC. Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2315-24. [PMID: 25740924 PMCID: PMC4407653 DOI: 10.1093/jxb/erv029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/04/2014] [Accepted: 01/09/2015] [Indexed: 05/09/2023]
Abstract
Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD.
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Affiliation(s)
- J G Pérez-Pérez
- Department of Citriculture, IMIDA, 30150 La Alberca, Murcia, Spain
| | - I C Dodd
- Centre for Sustainable Agriculture, Lancaster Environment Centre, University of Lancaster, Lancaster LA1 4YQ, Uk
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Porcel R, Zamarreño ÁM, García-Mina JM, Aroca R. Involvement of plant endogenous ABA in Bacillus megaterium PGPR activity in tomato plants. BMC PLANT BIOLOGY 2014; 14:36. [PMID: 24460926 PMCID: PMC3903769 DOI: 10.1186/1471-2229-14-36] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/23/2014] [Indexed: 05/08/2023]
Abstract
BACKGROUND Plant growth-promoting rhizobacteria (PGPR) are naturally occurring soil bacteria which benefit plants by improving plant productivity and immunity. The mechanisms involved in these processes include the regulation of plant hormone levels such as ethylene and abscisic acid (ABA). The aim of the present study was to determine whether the activity of Bacillus megaterium PGPR is affected by the endogenous ABA content of the host plant. The ABA-deficient tomato mutants flacca and sitiens and their near-isogenic wild-type parental lines were used. Growth, stomatal conductance, shoot hormone concentration, competition assay for colonization of tomato root tips, and root expression of plant genes expected to be modulated by ABA and PGPR were examined. RESULTS Contrary to the wild-type plants in which PGPR stimulated growth rates, PGPR caused growth inhibition in ABA-deficient mutant plants. PGPR also triggered an over accumulation of ethylene in ABA-deficient plants which correlated with a higher expression of the pathogenesis-related gene Sl-PR1b. CONCLUSIONS Positive correlation between over-accumulation of ethylene and a higher expression of Sl-PR1b in ABA-deficient mutant plants could indicate that maintenance of normal plant endogenous ABA content may be essential for the growth promoting action of B. megaterium by keeping low levels of ethylene production.
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Affiliation(s)
- Rosa Porcel
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (EEZ-CSIC), Profesor Albareda 1, 18008 Granada, Spain
| | - Ángel María Zamarreño
- CIPAV TimacAGRO International-Roullier Group, Polígono Arazuri-Orkoien, c/C no. 32, 31160-Orkoien, Navarra, Spain
| | - José María García-Mina
- CIPAV TimacAGRO International-Roullier Group, Polígono Arazuri-Orkoien, c/C no. 32, 31160-Orkoien, Navarra, Spain
| | - Ricardo Aroca
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (EEZ-CSIC), Profesor Albareda 1, 18008 Granada, Spain
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Kovalskaya N, Owens R, Baker CJ, Deahl K, Hammond RW. Application of a modified EDTA-mediated exudation technique and guttation fluid analysis for Potato spindle tuber viroid RNA detection in tomato plants (Solanum lycopersicum). J Virol Methods 2013; 198:75-81. [PMID: 24388932 DOI: 10.1016/j.jviromet.2013.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/26/2013] [Accepted: 12/17/2013] [Indexed: 11/29/2022]
Abstract
Potato spindle tuber viroid (PSTVd) is a small plant pathogenic circular RNA that does not encode proteins, replicates autonomously, and traffics systemically in infected plants. Long-distance transport occurs by way of the phloem; however, one report in the literature describes the presence of viroid RNA in the xylem ring of potato tubers. In this study, a modified method based on an EDTA-mediated phloem exudation technique was applied for detection of PSTVd in the phloem of infected tomato plants. RT-PCR, nucleic acid sequencing, and Southern blot analyses of RT-PCR products verified the presence of viroid RNA in phloem exudates. In addition, the guttation fluid collected from the leaves of PSTVd-infected tomato plants was analyzed revealing the absence of viroid RNA in the xylem sap. To our knowledge, this is the first report of PSTVd RNA detection in phloem exudates obtained by the EDTA-mediated exudation technique.
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Affiliation(s)
- Natalia Kovalskaya
- Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA; Institute of Ecological Soil Science of MV Lomonosov Moscow State University, Moscow 119991, Russia
| | - Robert Owens
- Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
| | - C Jacyn Baker
- Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
| | - Kenneth Deahl
- Genetic Improvement of Fruits and Vegetables Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
| | - Rosemarie W Hammond
- Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
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Brychkova G, Grishkevich V, Fluhr R, Sagi M. An essential role for tomato sulfite oxidase and enzymes of the sulfite network in maintaining leaf sulfite homeostasis. PLANT PHYSIOLOGY 2013; 161:148-64. [PMID: 23148079 PMCID: PMC3532248 DOI: 10.1104/pp.112.208660] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/12/2012] [Indexed: 05/19/2023]
Abstract
Little is known about the homeostasis of sulfite levels, a cytotoxic by-product of plant sulfur turnover. By employing extended dark to induce catabolic pathways, we followed key elements of the sulfite network enzymes that include adenosine-5'-phosphosulfate reductase and the sulfite scavengers sulfite oxidase (SO), sulfite reductase, UDP-sulfoquinovose synthase, and β-mercaptopyruvate sulfurtransferases. During extended dark, SO was enhanced in tomato (Solanum lycopersicum) wild-type leaves, while the other sulfite network components were down-regulated. SO RNA interference plants lacking SO activity accumulated sulfite, resulting in leaf damage and mortality. Exogenous sulfite application induced up-regulation of the sulfite scavenger activities in dark-stressed or unstressed wild-type plants, while expression of the sulfite producer, adenosine-5'-phosphosulfate reductase, was down-regulated. Unstressed or dark-stressed wild-type plants were resistant to sulfite applications, but SO RNA interference plants showed sensitivity and overaccumulation of sulfite. Hence, under extended dark stress, SO activity is necessary to cope with rising endogenous sulfite levels. However, under nonstressed conditions, the sulfite network can control sulfite levels in the absence of SO activity. The novel evidence provided by the synchronous dark-induced turnover of sulfur-containing compounds, augmented by exogenous sulfite applications, underlines the role of SO and other sulfite network components in maintaining sulfite homeostasis, where sulfite appears to act as an orchestrating signal molecule.
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