DOCSLIB.ORG

Sensing and Retrograde Signalling of Mitochondrial Metabolic States in Plants

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sensing and Retrograde Signalling of Mitochondrial Metabolic States in Plants Sensing and Retrograde Signalling of Mitochondrial Metabolic States in Plants Dissertation der Fakultät für Biologie der Ludwig-Maximilians-Universität München Vorgelegt von Ann-Christine König München, Juni 2014 Gutachter: Dr. Iris Finkemeier (Erstgutachter) Prof. Dr. Jörg Nickelsen (Zweitgutachter) Prof. Dr. Wolfgang Enard Prof. Dr. Thorsten Mascher PD. Dr. Bolle Prof. Dr. Günther Heubl Tag der Dissertations Abgabe: 18.06.2014 Tag der mündlichen Prüfung: 26.09.2014 Table of contents I. Summary 3 II. Zusammenfassung 5 III. Aim of Thesis 7 IV. List of Publications 9 V. Abbreviations 11 1. General Introduction 13 1.1 Main function of mitochondria in plants cells 14 1.2. Mitochondrial retrograde signaling in plants 16 1.3. Protein posttranslational modifications connected to mitochondrial metabolism 18 2. Summarizing Discussion 23 2.1. Dysfunctions in mitochondria result in transcriptional changes of distinct metabolic and regulatory pathways 23 2.2. Carboxylic acid treatment results in distinct changes of nuclear transcripts 26 2.3. Correlation between MRR and citrate-dependent transcriptional changes 31 2.4. Redox regulation of mitochondrial citrate synthase 33 2.5. Acetyl-CoA dependent lysine acetylation of mitochondrial proteins 35 2.6. The Arabidopsis sirtuin SRT2 fine tunes mitochondrial metabolism 40 3. Conclusion and Outlook 43 3.1. Future perspectives of transcriptional regulation triggered by citrate 44 3.2. Research outlook for lysine acetylation on metabolic enzymes 45 4. References 47 VI. Declaration of Own Contributions 57 VII. Curriculum Vitae 59 VIII. Eidesstattliche Erklärung 63 IX. Acknowledgements 65 X. Publications 1-7 67 I. Summary I. Summary Plants are exposed to always changing environmental conditions because of their sessile nature. For an optimal development and growth, plants have to be able to adapt to these changing conditions such as alterations in light intensities, temperature differences, salt stress as well as pathogen attacks. The acclimation of the plant metabolism can occur by the synthesis of new proteins which are directly or indirectly capable to protect cellular components from damage due to oxidative stress for example. Most sensitive to oxidative inhibition are metabolic pathways connected to electron transport chains which are housed in the plant organelles, mitochondria and chloroplasts, and which are the major energy sources for plant cells. Because both organelles lost most of their genomes during evolution, the majority of their required proteins are expressed in the nucleus, translated in the cytosol and posttranslationally imported into the target organelle. This requires a fine-tuned and constant communication between the nucleus and the organelles as well as interplay between chloroplasts and mitochondria themselves. Mitochondria indirectly provide reducing equivalents for the chloroplast and supply the cells with ATP in the dark and when ATP supply from chloroplasts is not sufficient. In this thesis, the communication of mitochondria with the nucleus and the posttranslational regulation of mitochondrial metabolic enzymes have been investigated. Mitochondria house the tricarboxylic acid (TCA) cycle in which acetyl-CoA and carboxylic acids are used in a series of decarboxylation reactions to produce reducing equivalents used during oxidative phosphorylation for ATP synthesis. As organic acids are the major players in the TCA cycle and they reflect both the redox and the metabolic state of the cell, they represent putative candidates to act as regulators of gene expression. We propose citrate as a possible signalling molecule to report on the metabolic state of mitochondria as it can be transported between organelles and we were able to demonstrate that perturbation in cellular citrate concentrations strongly correlate with changes in transcript abundances. After citrate treatment, the main functional affected gene targets were photosynthesis, cell wall, biotic stress, and protein synthesis. Similar categories were observed to be changed after mitochondrial impairment and therefore they were concluded as main targets of mitochondrial retrograde signalling. Additionally we showed that the transcript response to citrate is distinct from other organic acids and that induction of genes occurs in a time and concentration dependent manner. Intracellular mitochondrial citrate levels depend on the action of citrate synthase which we found to be redox-regulated. Citrate synthase is catalyzing the first committed step of the TCA cycle in which oxaloacetate and acetyl-CoA are converted to citrate. Our results indicate 3 I. Summary that citrate synthase can be deactivated by oxidation and reactivated by thioredoxin which probably enables the proper folding of citrate synthase. Further high molecular weight complexes of citrate synthase were observed either because of multimeric aggregates or association with high molecular weight complexes with proteins from oxidative phosphorylation (OXPHOS). By site-directed mutagenesis the cysteine residues important for activity and redox regulation of citrate synthase were discovered. Until now almost nothing was known about the posttranslational regulation of TCA cycle enzymes and here we provide first insight into the redox regulation of citrate synthase. Posttranslational modifications, like redox regulation, are in general efficient molecular mechanisms to modify the activity of important metabolic enzymes. A further yet largely unexplored posttranslational modification is the acetylation of the ε-amino group of lysine residues on proteins investigated in the third part of this thesis. Lysine acetylation is dependent on the acetyl-CoA pools and can be reverted by the action of lysine deacetylases. We explored the extent of lysine acetylation in plant mitochondria. By liquid chromatography–mass spectrometry (LC-MS/MS) analysis the acetylome of Arabidopsis mitochondria was revealed, including 120 proteins and 243 acetylated sites. All TCA cycle enzymes carry at least one acetylation site and several enzymes of OXPHOS were identified as lysine-acetylated. The high number of lysine-acetylated proteins suggests that this modification has a regulatory role in mitochondrial metabolism maybe under adverse environmental conditions. In in vitro analysis, the abundance of non-enzymatic lysine acetylation depending on elevated pH and acetyl-CoA concentrations has been investigated. Furthermore, we characterized a novel sirtuin-type lysine deacetylase, Silent Information Regulator2 homolog (SRT2) in Arabidopsis mitochondria. We were able to demonstrate that SRT2 is mainly localized at the inner mitochondrial membrane and is interacting with several protein complexes in energy metabolism such as complex I, the ATP/ADP carries, and a subunit of the ATP-synthase. An increased ADP uptake was discovered for the knockout mutant as well as changes in sugars and amino acid contents compared to wild type plants. In conclusion, this work provides a first insight into the fine-tuning of mitochondrial metabolism which is achieved by retrograde regulation and possibly mediated by citrate as signalling molecule. Furthermore, novel post-translational regulatory processes in Arabidopsis mitochondria were uncovered, such as the redox regulation of citrate synthase and the regulation of mitochondrial metabolism by lysine acetylation with SRT2 as active mitochondrial deacetylase. 4 II. Zusammenfassung II. Zusammenfassung Pflanzen sind durch ihre sessile Lebensweise ständig wechselnden Umweltbedingungen ausgesetzt. Für eine optimale Entwicklung und optimales Wachstum müssen Pflanzen dazu in der Lage sein, sich wechselnden Bedingungen wie Lichtintensität, Temperaturunterschiede, Salzstress und Pathogenbefall anzupassen. Die Adaption des Pflanzenmetabolismus kann zum Beispiel durch die Synthese oder Regulation von Proteinen erfolgen, die direkt oder indirekt dazu fähig sind zelluläre Bestandteile vor Schäden wie z.B. Oxidation zu bewahren. Besonders metabolische Vorgänge in den pflanzlichen Organellen, welche mit dem Transport von Elektronen verbunden sind, erweisen sich als sehr empfindlich gegenüber Oxidation. Da Mitochondrien und Chloroplasten im Laufe der Evolution den größten Teil ihres Genoms verloren haben, müssen benötigte Proteine im Zellkern exprimiert, im Zytosol translatiert und anschließend posttranslational in das Zielorganell importiert werden. Dies setzt eine Feinregulation und ständige Kommunikation zwischen dem Zellkern und den Organellen voraus. Im Zuge dieser Arbeit wurde sowohl die Kommunikation zwischen Mitochondrien und dem Zellkern, als auch die posttranslationale Regulation mitochondrialer metabolischer Enzyme untersucht. In Mitochondrien findet der Citratzyklus statt, in welchem Reduktionsäquivalente aus Acetyl-CoA und Carbonsäuren in einer Reihe von Decarboxylierungsreaktionen gewonnen werden. Diese werden in der Oxidativen Phosphorylierung (OXPHOS) zur ATP-Produktion verwendet. Die Konzentrationen der Carbonsäuren des Citratzyklus spiegeln den Redoxstatus und den metabolischen Zustand der Mitochondrien wieder. Aus diesem Grund sind Carbonsäuren mögliche Kandidaten, welche an der Regulation der Genexpression beteiligt sein könnten. Citrat besitzt die Grundvoraussetzungen um als Signalmolekül mitochondrialer metabolischer Zustände zu dienen, da es zwischen den Organellen transportiert werden kann. In dieser Arbeit konnte gezeigt werden, dass die zelluläre Citratkonzentration einen starken Einfluss auf den Transkriptionsspiegel hat. Nach der Behandlung
Load more

Recommended publications
  • ATP-Citrate Lyase Has an Essential Role in Cytosolic Acetyl-Coa Production in Arabidopsis Beth Leann Fatland Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2002 ATP-citrate lyase has an essential role in cytosolic acetyl-CoA production in Arabidopsis Beth LeAnn Fatland Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Molecular Biology Commons, and the Plant Sciences Commons Recommended Citation Fatland, Beth LeAnn, "ATP-citrate lyase has an essential role in cytosolic acetyl-CoA production in Arabidopsis " (2002). Retrospective Theses and Dissertations. 1218. https://lib.dr.iastate.edu/rtd/1218 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. ATP-citrate lyase has an essential role in cytosolic acetyl-CoA production in Arabidopsis by Beth LeAnn Fatland A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Plant Physiology Program of Study Committee: Eve Syrkin Wurtele (Major Professor) James Colbert Harry Homer Basil Nikolau Martin Spalding Iowa State University Ames, Iowa 2002 UMI Number: 3158393 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted.
    [Show full text]
  • Characterization of the CRM Gene Family and Elucidating the Function of Oscfm2 in Rice
    biomolecules Article Characterization of the CRM Gene Family and Elucidating the Function of OsCFM2 in Rice Qiang Zhang y , Lan Shen y, Deyong Ren, Jiang Hu, Li Zhu, Zhenyu Gao, Guangheng Zhang , Longbiao Guo, Dali Zeng and Qian Qian * State Key Laboratory of Rice Biology/China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China; [email protected] (Q.Z.); [email protected] (L.S.); [email protected] (D.R.); [email protected] (J.H.); [email protected] (L.Z.); [email protected] (Z.G.); [email protected] (G.Z.); [email protected] (L.G.); [email protected] (D.Z.) * Correspondence: [email protected]; Tel.: +86-571-6337-0483 These authors contributed equally to this work. y Received: 10 January 2020; Accepted: 17 February 2020; Published: 18 February 2020 Abstract: The chloroplast RNA splicing and ribosome maturation (CRM) domain-containing proteins regulate the expression of chloroplast or mitochondrial genes that influence plant growth and development. Although 14 CRM domain proteins have previously been identified in rice, there are few studies of these gene expression patterns in various tissues and under abiotic stress. In our study, we found that 14 CRM domain-containing proteins have a conservative motif1. Under salt stress, the expression levels of 14 CRM genes were downregulated. However, under drought and cold stress, the expression level of some CRM genes was increased. The analysis of gene expression patterns showed that 14 CRM genes were expressed in all tissues but especially highly expressed in leaves. In addition, we analyzed the functions of OsCFM2 and found that this protein influences chloroplast development by regulating the splicing of a group I and five group II introns.
    [Show full text]
  • Molecular Mechanism for the Interaction Between Gibberellin and Brassinosteroid Signaling Pathways in Arabidopsis
    Molecular mechanism for the interaction between gibberellin and brassinosteroid signaling pathways in Arabidopsis Javier Gallego-Bartoloméa, Eugenio G. Mingueta, Federico Grau-Enguixa, Mohamad Abbasa, Antonella Locascioa, Stephen G. Thomasb, David Alabadía,1, and Miguel A. Blázqueza aInstituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, 46022 Valencia, Spain; and bRothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom Edited by Mark Estelle, University of California at San Diego, La Jolla, CA, and approved July 10, 2012 (received for review December 5, 2011) Plant development is modulated by the convergence of multiple response to auxin (10) and thus provides one of the possible environmental and endogenous signals, and the mechanisms that molecular mechanisms explaining the synergistic effect that both allow the integration of different signaling pathways is currently hormones exert on the expression of many genes (11). being unveiled. A paradigmatic case is the concurrence of brassinos- GAs and BRs regulate common physiological responses, e.g., teroid (BR) and gibberellin (GA) signaling in the control of cell expan- as illustrated by the dwarf phenotype of the GA- and BR-de- sion during photomorphogenesis, which is supported by phys- ficient mutants (6, 12). Moreover, both hormones act synergisti- iological observations in several plants but for which no molecular cally to promote hypocotyl elongation of light-grown Arabidopsis mechanism has been proposed. In this work, we show that the in- seedlings (13), a behavior that, as with BRs and auxin, might be tegration of these two signaling pathways occurs through the phys- interpreted as an indication of interaction between the two ical interaction between the DELLA protein GAI, which is a major pathways.
    [Show full text]
  • Integration of Auxin and Brassinosteroid Pathways by Auxin Response Factor 2
    Integration of auxin and brassinosteroid pathways by Auxin Response Factor 2 Gre´ gory Vert†, Cristina L. Walcher‡, Joanne Chory§¶, and Jennifer L. Nemhauser‡¶ †Biochimie and Physiologie Mole´culaire des Plantes, Centre National de la Recherche Scientifique, Unite´Mixte de Recherche 5004, Institut de Biologie Inte´grative des Plantes, 2 Place Viala, 34060 Montpellier Cedex 1, France; ‡Department of Biology, University of Washington, Box 351800, Seattle, WA 98195-1800; and §Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037 Contributed by Joanne Chory, April 25, 2008 (sent for review March 5, 2008) Plant form is shaped by a complex network of intrinsic and extrinsic bind and activate transcription on the promoters of genes like signals. Light-directed growth of seedlings (photomorphogenesis) SAUR-15, common to both auxin and BR pathways (13). BRs depends on the coordination of several hormone signals, including regulate the activity of BES1 and BZR1 by modulating their brassinosteroids (BRs) and auxin. Although the close relationship phosphorylation status, dependent on the coordinate action of between BRs and auxin has been widely reported, the molecular the BIN2 GSK3 kinase and the BSU1 phosphatase, and respec- mechanism for combinatorial control of shared target genes has tive family members (7, 15–18). Phosphorylation by BIN2 in- remained elusive. Here we demonstrate that BRs synergistically hibits homodimerization by BES1, thereby blocking DNA- increase seedling sensitivity to auxin and show that combined binding and transcriptional activation (17), and modulates the treatment with both hormones can increase the magnitude and dynamics of BZR1 in the cell by interaction with a 14-3-3 protein duration of gene expression.
    [Show full text]
  • ( 12 ) Patent Application Publication ( 10 ) Pub . No .: US 2020/0407740 A1 CUI Et Al
    US 20200407740A1 IN ( 19 ) United States ( 12 ) Patent Application Publication ( 10 ) Pub . No .: US 2020/0407740 A1 CUI et al. ( 43 ) Pub . Date : Dec. 31 , 2020 ( 54 ) MATERIALS AND METHODS FOR Publication Classification CONTROLLING BUNDLE SHEATH CELL ( 51 ) Int. CI . FATE AND FUNCTION IN PLANTS C12N 15/82 ( 2006.01 ) ( 71 ) Applicant: FLORIDA STATE UNIVERSITY ( 52 ) U.S. CI . RESEARCH FOUNDATION , INC . , CPC C12N 15/8225 ( 2013.01 ) ; C12N 15/8269 Tallahassee, FL ( US ) ( 2013.01 ) ; C12N 15/8261 ( 2013.01 ) ( 57 ) ABSTRACT ( 72 ) Inventors : HONGCHANG CUI , The subject invention concerns materials and methods for TALLAHASSEE , FL (US ); DANYU increasing and / or improving photosynthetic efficiency in KONG , BLACKSBURG , VA (US ); plants, and in particular, C3 plants. In particular, the subject YUELING HAO , TALLAHASSEE , FL invention provides for means to increase the number of ( US ) bundle sheath ( BS ) cells in plants , to improve the efficiency of photosynthesis in BS cells , and to increase channels between BS and mesophyll ( M ) cells . In one embodiment, a ( 21 ) Appl . No .: 17 / 007,043 method of the invention concerns altering the expression level or pattern of one or more of SHR , SCR , and / or SCL23 in a plant. The subject invention also pertains to genetically ( 22 ) Filed : Aug. 31 , 2020 modified plants , and in particular, C3 plants, that exhibit increased expression of one or more of SHR , SCR , and / or SCL23 . Transformed and transgenic plants are contemplated Related U.S. Application Data within the scope of the invention . The subject invention also ( 62 ) Division of application No. 14 / 898,046 , filed on Dec. concerns methods for increasing expression of photosyn 11 , 2015 , filed as application No.
    [Show full text]
  • The CRM Domain: an RNA Binding Module Derived from an Ancient Ribosome-Associated Protein
    JOBNAME: RNA 13#1 2007 PAGE: 1 OUTPUT: Thursday December 7 00:09:11 2006 csh/RNA/127813/rna1396 Downloaded from rnajournal.cshlp.org on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press The CRM domain: An RNA binding module derived from an ancient ribosome-associated protein ALICE BARKAN,1 LARIK KLIPCAN,2 OREN OSTERSETZER,2 TETSUYA KAWAMURA,1,3 YUKARI ASAKURA,1 and KENNETH P. WATKINS1 1Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229, USA 2Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel ABSTRACT The CRS1–YhbY domain (also called the CRM domain) is represented as a stand-alone protein in Archaea and Bacteria, and in a family of single- and multidomain proteins in plants. The function of this domain is unknown, but structural data and the presence of the domain in several proteins known to interact with RNA have led to the proposal that it binds RNA. Here we describe a phylogenetic analysis of the domain, its incorporation into diverse proteins in plants, and biochemical properties of a prokaryotic and eukaryotic representative of the domain family. We show that a bacterial member of the family, Escherichia coli YhbY, is associated with pre-50S ribosomal subunits, suggesting that YhbY functions in ribosome assembly. GFP fused to a single-domain CRM protein from maize localizes to the nucleolus, suggesting that an analogous activity may have been retained in plants. We show further that an isolated maize CRM domain has RNA binding activity in vitro, and that a small motif shared with KH RNA binding domains, a conserved ‘‘GxxG’’ loop, contributes to its RNA binding activity.
    [Show full text]
  • PIN-LIKES Coordinate Brassinosteroid Signalling with Nuclear Auxin Input in Arabidopsis Thaliana
    bioRxiv preprint doi: https://doi.org/10.1101/646489; this version posted July 19, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. PIN-LIKES coordinate brassinosteroid signalling with nuclear auxin input in Arabidopsis thaliana Authors: Lin Sun1, Elena Feraru1, Mugurel I. Feraru1, Krzysztof Wabnik2, Jürgen Kleine-Vehn1,* Affiliations: 1Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190 Vienna, Austria 2Centro de Biotecnología y Genómica de Plantas (Universidad Politécnica de Madrid - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria), Autopista M-40, Km 38 - 28223 Pozuelo de Alarcón, Spain *Correspondence should be addressed to J.K.-V. ([email protected]) 1 bioRxiv preprint doi: https://doi.org/10.1101/646489; this version posted July 19, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Abstract Auxin and brassinosteroids (BR) are crucial growth regulators and display overlapping functions during plant development. Here, we reveal an alternative phytohormone crosstalk mechanism, revealing that brassinosteroid signaling controls nuclear abundance of auxin. We performed a forward genetic screen for imperial pils (imp) mutants that enhance the overexpression phenotypes of PIN-LIKES (PILS) putative intracellular auxin transport facilitator. Here we report that the imp1 mutant is defective in the brassinosteroid-receptor BRI1. Our data reveals that BR signaling transcriptionally and posttranslationally represses accumulation of PILS proteins at the endoplasmic reticulum, thereby increasing nuclear abundance and signaling of auxin.
    [Show full text]
  • Brassinosteroid Regulation of Wood Formation in Poplar
    Research Brassinosteroid regulation of wood formation in poplar Juan Du1,2,3*, Suzanne Gerttula3*, Zehua Li2, Shu-Tang Zhao2, Ying-Li Liu2, Yu Liu1, Meng-Zhu Lu2,4 and Andrew T. Groover3,5 1College of Life Sciences, Zhejiang University, 866 Yu Hang tang Road, Hangzhou 310058, China; 2State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; 3Pacific Southwest Research Station, US Forest Service, Davis, CA 95618, USA; 4State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang Agriculture and Forest University, Hangzhou 311300, China; 5Department of Plant Biology, University of California Davis, Davis, CA 95616, USA Summary Authors for correspondence: Brassinosteroids have been implicated in the differentiation of vascular cell types in herba- Meng-Zhu Lu ceous plants, but their roles during secondary growth and wood formation are not well Tel: +1 86 10 62872015 defned. Email: [email protected] Here we pharmacologically and genetically manipulated brassinosteroid levels in poplar Andrew Groover trees and assayed the effects on secondary growth and wood formation, and on gene expres- Tel: +1 530 759 1738 sion within stems. Email: [email protected] Elevated brassinosteroid levels resulted in increases in secondary growth and tension wood Received: 6 March 2019 formation, while inhibition of brassinosteroid synthesis resulted in decreased growth and sec- Accepted: 30 April 2019 ondary vascular differentiation. Analysis of gene expression showed that brassinosteroid action is positively associated with genes involved in cell differentiation and cell-wall biosyn- New Phytologist (2020) 225: 1516–1530 thesis. doi: 10.1111/nph.15936 The results presented here show that brassinosteroids play a foundational role in the regula- tion of secondary growth and wood formation, in part through the regulation of cell differen- tiation and secondary cell wall biosynthesis.
    [Show full text]
  • Q&A: What Are Brassinosteroids and How Do They Act in Plants?
    Tang et al. BMC Biology (2016) 14:113 DOI 10.1186/s12915-016-0340-8 QUESTION AND ANSWER Open Access Q&A: what are brassinosteroids and how do they act in plants? Jiao Tang1,2,3, Zhifu Han1,2 and Jijie Chai1,2* showed that the reactions induced by these ingredients Abstract were different from those induced by gibberellins [8]. Brassinosteroids (BRs) are a class of polyhydroxylated They therefore speculated that these ingredients were a steroidal phytohormones in plants with similar new class of hormones, termed brassins. This hypothesis, structures to animals’ steroid hormones. however, was not accepted by some other researchers, Brassinosteroids regulate a wide range of physiological who argued that the physiological activities of the ingredi- processes including plant growth, development and ents could have been caused by gibberellin due to the immunity. Brassinosteroid signalling and its integration crude nature of the extract from which brassins were with other signalling pathways have been investigated identified [9]. Given the potential applications of brassins thoroughly at the molecular level. in agriculture, efforts organized by the US Department of Agriculture led to purification of 4 mg of brassins from 500 pounds of bee-collected Brassica pollen. The crystal What are the plant steroid hormones structure of the purified brassins was then solved and brassinosteroids? brassinolide was identified as the active component [10]. Brasinosteroids, defined as the sixth plant hormone after These findings marked the discovery of the first plant the classic plant hormones auxin, gibberellins, cytokinin, steroidal hormone. Currently, nearly 70 kinds of natural abscisic acid and ethylene, are analogous to animal steroid brassinolide analogues have been isolated from tissues of hormones in structure [1, 2].
    [Show full text]
  • The Mitochondrial Pentatricopeptide Repeat Protein PPR18 Is Required for the Cis-Splicing of Nad4 Intron 1 and Essential to Seed Development in Maize
    International Journal of Molecular Sciences Article The Mitochondrial Pentatricopeptide Repeat Protein PPR18 Is Required for the cis-Splicing of nad4 Intron 1 and Essential to Seed Development in Maize Rui Liu 1, Shi-Kai Cao 1 , Aqib Sayyed 1, Chunhui Xu 1, Feng Sun 1, Xiaomin Wang 2 and Bao-Cai Tan 1,* 1 Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; [email protected] (R.L.); [email protected] (S.-K.C.); [email protected] (A.S.); [email protected] (C.X.); [email protected] (F.S.) 2 Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; [email protected] * Correspondence: [email protected] Received: 10 May 2020; Accepted: 2 June 2020; Published: 5 June 2020 Abstract: Pentatricopeptide repeat (PPR) protein comprises a large family, participating in various aspects of organellar RNA metabolism in land plants. There are approximately 600 PPR proteins in maize, but the functions of many PPR proteins remain unknown. In this study, we defined the function of PPR18 in the cis-splicing of nad4 intron 1 in mitochondria and seed development in maize. Loss function of PPR18 seriously impairs embryo and endosperm development, resulting in the empty pericarp (emp) phenotype in maize. PPR18 encodes a mitochondrion-targeted P-type PPR protein with 18 PPR motifs. Transcripts analysis indicated that the splicing of nad4 intron 1 is impaired in the ppr18 mutant, resulting in the absence of nad4 transcript, leading to severely reduced assembly and activity of mitochondrial complex I and dramatically reduced respiration rate.
    [Show full text]
  • Integrative Comparative Analyses of Metabolite And
    UC Davis UC Davis Previously Published Works Title Integrative comparative analyses of metabolite and transcript profiles uncovers complex regulatory network in tomato (Solanum lycopersicum L.) fruit undergoing chilling injury. Permalink https://escholarship.org/uc/item/5nk3w5vc Journal Scientific reports, 9(1) ISSN 2045-2322 Authors Zhang, Wen-Fa Gong, Ze-Hao Wu, Meng-Bo et al. Publication Date 2019-03-14 DOI 10.1038/s41598-019-41065-9 Peer reviewed eScholarship.org Powered by the California Digital Library University of California www.nature.com/scientificreports OPEN Integrative comparative analyses of metabolite and transcript profles uncovers complex regulatory Received: 22 June 2018 Accepted: 27 February 2019 network in tomato (Solanum Published: xx xx xxxx lycopersicum L.) fruit undergoing chilling injury Wen-Fa Zhang1, Ze-Hao Gong1, Meng-Bo Wu1, Helen Chan2, Yu-Jin Yuan1, Ning Tang1, Qiang Zhang1, Ming-Jun Miao3, Wei Chang3, Zhi Li3, Zheng-Guo Li1, Liang Jin1 & Wei Deng1 Tomato fruit are especially susceptible to chilling injury (CI) when continuously exposed to temperatures below 12 °C. In this study, integrative comparative analyses of transcriptomics and metabolomics data were performed to uncover the regulatory network in CI tomato fruit. Metabolite profling analysis found that 7 amino acids, 27 organic acids, 16 of sugars and 22 other compounds had a signifcantly diferent content while transcriptomics data showed 1735 diferentially expressed genes (DEGs) were down-regulated and 1369 were up-regulated in cold-stored fruit. We found that the contents of citrate, cis-aconitate and succinate were increased, which were consistent with the expression of ATP-citrate synthase (ACS) and isocitrate dehydrogenase (IDH) genes in cold-treated tomato fruit.
    [Show full text]
  • Regulated Drought Stress Response in Arabidopsis Thaliana Buyun Tang Iowa State University
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 The molecular mechanisms of brassinosteroid- regulated drought stress response in Arabidopsis thaliana Buyun Tang Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Agriculture Commons, Genetics Commons, Molecular Biology Commons, and the Plant Biology Commons Recommended Citation Tang, Buyun, "The molecular mechanisms of brassinosteroid-regulated drought stress response in Arabidopsis thaliana" (2015). Graduate Theses and Dissertations. 14423. https://lib.dr.iastate.edu/etd/14423 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. The molecular mechanisms of brassinosteroid-regulated drought stress response in Arabidopsis thaliana by Buyun Tang A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Plant Biology Program of Study Committee: Yanhai Yin, Major Professor Steven Rodermel Thomas Peterson Iowa State University Ames, Iowa 2015 Copyright © Buyun Tang, 2015. All rights reserved. ii TABLE OF CONTENTS Page CHAPTER 1. GENERAL INTRODUCTION 1 1.1 Brassinosteroid Signaling Pathway 1 1.2 Drought and Abscisic Acid Signaling Pathway 3 1.3 Objectives and Significance 6 1.4 Thesis Organization 7 1.5 References 8 1.6 Figures 12 CHAPTER 2. THE INTERACTION BETWEEN BES1 AND RD26 MEDIATES THE CROSSTALK BETWEEN BRASSINOSTEROID AND DROUGHT SIGNALING PATHWAYS 15 2.1 Abstract 15 2.2 Introduction 16 2.3 Results 18 2.4 Discussion 21 2.5 Materials and Methods 23 2.6 Acknowledgments 24 2.7 References 25 2.8 Figures 27 CHAPTER 3.
    [Show full text]