DOCSLIB.ORG

Understanding the Genetic Basis for Competitive Nodule Formation by Clover Rhizobia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Understanding the genetic basis for competitive nodule formation by clover rhizobia Shaun Ferguson (MSc) A thesis submitted for the degree of Doctor of Philosophy Department of Microbiology and Immunology, The University of Otago, Dunedin New Zealand December 31st, 2018 Abstract Clovers enter a symbiotic relationship with particular rhizobia through a highly specific and complex signal exchange culminating in the formation of nitrogen-fixing root nodules. Legumes exude flavonoids that are perceived by compatible rhizobia through a LysR-type regulator NodD. Activated NodD mediates expression of the nodulation (nod) genes, which produce a cocktail of signalling molecules known as Nod factors (NF). Recognition of NF by compatible legumes initiates nodule formation. Distinct strains of the clover-nodulating species, Rhizobium leguminosarum bv. trifolii (Rlt), vary in their ability to nodulate different clover species effectively, and to form nodules in competition with other strains. This is important agriculturally as indigenous strains often outcompete added inoculum strains that are superior at nitrogen fixation. We investigated the genetic determinants of varying host responses between three Rlt strains that differed in their ability to form efficient symbioses on white, red and subterranean clovers. To determine whether differences in nod gene expression contributed to this host specificity or competitive ability, we investigated the induction of nodA and nodF promoters from the three strains. The studies revealed significant variation in nod gene expression in response to flavonoid 7,4’-dihydroxyflavone, due to both the host strain background and the particular promoter. The strength of promoter expression of nodA or nodF also appeared to correlate with the competitive ability of the Rlt strain. We also showed that expression of the nodF operon had a non-equal influence on symbiotic proficiency depending on the Rlt strain, and elevated nodF expression appeared to enhance nodulation of annual clover species. Distinct phenological barriers exist that generally limit efficient Rlt symbiosis to either annual or perennial clover hosts. We found that Rlt nod gene expression profiles correlate with success on a specific type of host. We suggest that a two receptor system exists in clover, where following entry via a broad-spectrum receptor, a stringent cortical receptor distinguishes the NF profile produced, providing greater compatibility scrutiny by the host. Previously Rhizobium leguminosarum species were considered to contain a single copy of nodD. However we showed that some strains of Rlt contain a second copy of nodD, designated nodD2. Single and double nodD1 and nodD2 markerless deletion mutants i were constructed in Rlt strain TA1. The nodD1 deletion mutant revealed only a slight reduction in nodulation on white clover, whereas deletion of both copies of nodD resulted in abolished nodulation, which was restored by complementation with either nodD1 or nodD2. Together these results provided evidence of a functional NodD2 in some strains of Rlt. Moreover, we demonstrated that NodD1 and NodD2 show significant differences in their capacity to induce nod gene expression and infection thread (IT) formation. NodD1 and NodD2 protein structure predictions suggested variation in their flavonoid binding pockets, and furthermore NodD2 appeared to confer the ability to nodulate a broader range of hosts. Significantly, competition studies revealed an important role for NodD2 in competitive nodule formation on white clover. nodD2 was found in the genomes of eight out of 13 strains of Rlt investigated, and was absent from the 13 strains with genome sequence available of another biovar of the same species, Rhizobium leguminosarum bv. viciae (Rlv). It appeared that nodD2 arose via two distinct genetic mechanisms, duplication in some strains and horizontal acquisition in others. Phylogenetic analysis of the Rlt NodD sequences revealed distinct clustering relating to the phenological distinction of the hosts. There was a correlation between the presence of NodD2 and the ability to form effective symbiosis with perennial clover hosts. We propose that NodD2 responds to a different inducer than NodD1 that is produced in the cortical cells of the host, and results in a specific NF profile that is perceived by the stringent cortical receptor, required for efficient and competitive infection of perennial clovers. A pipeline for transcriptomic analysis of clover rhizosphere-grown Rlt was developed with promising early results. Despite a limited exploratory investigation, two of three genes chosen for investigation revealed a slight competitive disadvantage when deleted. This RNA-seq analysis has provided a basis for future large scale in-depth transcriptomic analysis to determine genetic traits contributing to rhizosphere competence. In summary, we have determined several genetic traits to be utilised as selection criteria for highly competitive inoculant strains. Furthermore, the transcriptomic pipeline developed will enable identification of further genetic factors contributing to successful symbiosis to also be used as selection criteria for high-quality clover inoculants in NZ. ii Acknowledgements The first person I would like to thank is my Supervisor Professor Clive Ronson. I have spent years working in his lab and I am extremely grateful for his constant support throughout my studies. His knowledge and insight has helped guide me to where I am now. I would like to thank the members of the Department of Microbiology and Immunology, and in particular, the 6th floor crew. I would especially like to thank members of lab 607, specifically Anthony Major, whom I worked closely with throughout this project, and Dr John Sullivan for putting up with my constant questions and for teaching me most of what I know in the lab. Additionally I would like to thank Dr. Josh Ramsay for his processing of the RNA-seq data, and Ben Perry for giving up his time to teach me how to perform these analyses for myself in the future. I am grateful that I could be a part of the MBIE collaboration and work towards a meaningful and practical goal, and for the knowledge and advice that came from our correspondence. Furthermore my studies would not have been possible without the financial assistance provided by the fund, for which I am extremely thankful. I am also very thankful for the financial support provided by the Department of Microbiology and Immunology which supported me at the end of my work and also helped me attend conferences which were amazing experiences I would have otherwise never had. I am very appreciative for the opportunity provided by Professor Philip Poole to spend time at the University of Oxford, and a special thanks to Dr Vinoy Ramachandran for all the time he put in to pass on his expertise on RNA-seq. Finally I am eternally grateful for the love and support of my family throughout, and for my partner Emily for constantly being there when I needed her. I could not have achieved this without them. iii Table of contents Abstract ................................................................................................................................................. i Acknowledgements ........................................................................................................................ iii Table of Figures ................................................................................................................................ix Table of Tables ............................................................................................................................... xiii List of Abbreviations...................................................................................................................... xv 1 General Introduction ............................................................................................................... 1 1.1 Overview ........................................................................................................................................ 2 1.2 Nitrogen fixation ............................................................................................................................ 4 1.2.1 Biological nitrogen fixation ..................................................................................................... 4 1.3 Agriculture in New Zealand ........................................................................................................... 4 1.3.1 Costs associated with nitrogen fertiliser use .......................................................................... 5 1.3.2 Issues with the current commercial exploitation of the rhizobium-legume symbiosis ......... 6 1.4 Rhizobium leguminosarum ............................................................................................................ 7 1.4.1 Classification and features...................................................................................................... 7 1.4.2 Rhizobium leguminosarum bv. trifolii strains of interest in this study ................................... 7 1.4.3 Variation in symbiotic proficiency .......................................................................................... 8 1.5 Trifolium legumes .......................................................................................................................... 8 1.5.1 The main Trifolium species of interest in this study ..............................................................
Recommended publications
  • Pfc5813.Pdf (9.887Mb)

    Pfc5813.Pdf (9.887Mb)

    UNIVERSIDAD POLITÉCNICA DE CARTAGENA ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA AGRONÓMICA DEPARTAMENTO DE PRODUCCIÓN VEGETAL INGENIERO AGRÓNOMO PROYECTO FIN DE CARRERA: “AISLAMIENTO E IDENTIFICACIÓN DE LOS RIZOBIOS ASOCIADOS A LOS NÓDULOS DE ASTRAGALUS NITIDIFLORUS”. Realizado por: Noelia Real Giménez Dirigido por: María José Vicente Colomer Francisco José Segura Carreras Cartagena, Julio de 2014. ÍNDICE GENERAL 1. Introducción…………………………………………………….…………………………………………………1 1.1. Astragalus nitidiflorus………………………………..…………………………………………………2 1.1.1. Encuadre taxonómico……………………………….…..………………………………………………2 1.1.2. El origen de Astragalus nitidiflorus………………………………………………………………..4 1.1.3. Descripción de la especie………..…………………………………………………………………….5 1.1.4. Biología…………………………………………………………………………………………………………7 1.1.4.1. Ciclo vegetativo………………….……………………………………………………………………7 1.1.4.2. Fenología de la floración……………………………………………………………………….9 1.1.4.3. Sistema de reproducción……………………………………………………………………….10 1.1.4.4. Dispersión de los frutos…………………………………….…………………………………..11 1.1.4.5. Nodulación con Rhizobium…………………………………………………………………….12 1.1.4.6. Diversidad genética……………………………………………………………………………....13 1.1.5. Ecología………………………………………………………………………………………………..…….14 1.1.6. Corología y tamaño poblacional……………………………………………………..…………..15 1.1.7. Protección…………………………………………………………………………………………………..18 1.1.8. Amenazas……………………………………………………………………………………………………19 1.1.8.1. Factores bióticos…………………………………………………………………………………..19 1.1.8.2. Factores abióticos………………………………………………………………………………….20 1.1.8.3. Factores antrópicos………………..…………………………………………………………….21
  • Actes Congrès MICROBIOD 1

    Actes Congrès MICROBIOD 1

    Actes du congrès international "Biotechnologie microbienne au service du développement" (MICROBIOD) Marrakech, MAROC 02-05 Novembre 2009 "Ce travail est publié avec le soutien du Ministère de l'Education Nationale, de l'Enseignement Supérieur, de la Formation des Cadres et de la Recherche Scientifique et du CNRST". MICROBIONA Edition www.ucam.ac.ma/microbiona 1 1 Mot du Comité d'organisation Cher (e) membre de MICROBIONA Cher(e) Participant(e), Sous le Haut Patronage de sa Majesté le Roi Mohammed VI, l'Association MICROBIONA et la Faculté des Sciences Semlalia, Université Cadi Ayyad, organisent du 02 au 05 Novembre 2009, en collaboration avec la Société Française de Microbiologie, le Pôle de Compétences Eau et Environnement et l'Incubateur Universitaire de Marrakech, le congrès international "Biotechnologie microbienne au service du développement" (MICROBIOD). Cette manifestation scientifique spécialisée permettra la rencontre de chercheurs de renommée internationale dans le domaine de la biotechnologie microbienne. Le congrès MICROBIOD est une opportunité pour les participants de mettre en relief l’importance socio-économique et environnementale de la valorisation et l’application de nouvelles techniques de biotechnologie microbienne dans divers domaines appliquées au développement et la gestion durable des ressources, à savoir l’agriculture, l'alimentation, l'environnement, la santé, l’industrie agro-alimentaire et le traitement et recyclage des eaux et des déchets par voie microbienne. Ce congrès sera également l’occasion pour les enseignants-chercheurs et les étudiants-chercheurs marocains d’actualiser leurs connaissances dans le domaine des biotechnologies microbiennes, qui serviront à l’amélioration de leurs recherches et enseignements. Le congrès MICROBIOD sera également l’occasion pour certains de nos collaborateurs étrangers de contribuer de près à la formation de nos étudiants en biotechnologie microbienne et ceci par la discussion des protocoles de travail, des méthodes d’analyse et des résultats obtenus.
  • Revised Taxonomy of the Family Rhizobiaceae, and Phylogeny of Mesorhizobia Nodulating Glycyrrhiza Spp

    Revised Taxonomy of the Family Rhizobiaceae, and Phylogeny of Mesorhizobia Nodulating Glycyrrhiza Spp

    Division of Microbiology and Biotechnology Department of Food and Environmental Sciences University of Helsinki Finland Revised taxonomy of the family Rhizobiaceae, and phylogeny of mesorhizobia nodulating Glycyrrhiza spp. Seyed Abdollah Mousavi Academic Dissertation To be presented, with the permission of the Faculty of Agriculture and Forestry of the University of Helsinki, for public examination in lecture hall 3, Viikki building B, Latokartanonkaari 7, on the 20th of May 2016, at 12 o’clock noon. Helsinki 2016 Supervisor: Professor Kristina Lindström Department of Environmental Sciences University of Helsinki, Finland Pre-examiners: Professor Jaakko Hyvönen Department of Biosciences University of Helsinki, Finland Associate Professor Chang Fu Tian State Key Laboratory of Agrobiotechnology College of Biological Sciences China Agricultural University, China Opponent: Professor J. Peter W. Young Department of Biology University of York, England Cover photo by Kristina Lindström Dissertationes Schola Doctoralis Scientiae Circumiectalis, Alimentariae, Biologicae ISSN 2342-5423 (print) ISSN 2342-5431 (online) ISBN 978-951-51-2111-0 (paperback) ISBN 978-951-51-2112-7 (PDF) Electronic version available at http://ethesis.helsinki.fi/ Unigrafia Helsinki 2016 2 ABSTRACT Studies of the taxonomy of bacteria were initiated in the last quarter of the 19th century when bacteria were classified in six genera placed in four tribes based on their morphological appearance. Since then the taxonomy of bacteria has been revolutionized several times. At present, 30 phyla belong to the domain “Bacteria”, which includes over 9600 species. Unlike many eukaryotes, bacteria lack complex morphological characters and practically phylogenetically informative fossils. It is partly due to these reasons that bacterial taxonomy is complicated.
  • Defining the Rhizobium Leguminosarum Species Complex

    Defining the Rhizobium Leguminosarum Species Complex

    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 December 2020 doi:10.20944/preprints202012.0297.v1 Article Defining the Rhizobium leguminosarum species complex J. Peter W. Young 1,*, Sara Moeskjær 2, Alexey Afonin 3, Praveen Rahi 4, Marta Maluk 5, Euan K. James 5, Maria Izabel A. Cavassim 6, M. Harun-or Rashid 7, Aregu Amsalu Aserse 8, Benjamin J. Perry 9, En Tao Wang 10, Encarna Velázquez 11, Evgeny E. Andronov 12, Anastasia Tampakaki 13, José David Flores Félix 14, Raúl Rivas González 11, Sameh H. Youseif 15, Marc Lepetit 16, Stéphane Boivin 16, Beatriz Jorrin 17, Gregory J. Kenicer 18, Álvaro Peix 19, Michael F. Hynes 20, Martha Helena Ramírez-Bahena 21, Arvind Gulati 22 and Chang-Fu Tian 23 1 Department of Biology, University of York, York YO10 5DD, UK 2 Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark; [email protected] 3 Laboratory for genetics of plant-microbe interactions, ARRIAM, Pushkin, 196608 Saint-Petersburg, Russia; [email protected] 4 National Centre for Microbial Resource, National Centre for Cell Science, Pune, India; [email protected] 5 Ecological Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; [email protected] (M.M.); [email protected] (E.K.J.) 6 Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA; [email protected] 7 Biotechnology Division, Bangladesh Institute of Nuclear Agriculture (BINA), Bangladesh; [email protected] 8 Ecosystems and Environment Research programme , Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Finland; [email protected] 9 Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand; [email protected] 10 Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Cd.
  • Analysis of the Interaction Between Pisum Sativum L. and Rhizobium Laguerreae Strains Nodulating This Legume in Northwest Spain

    Analysis of the Interaction Between Pisum Sativum L. and Rhizobium Laguerreae Strains Nodulating This Legume in Northwest Spain

    plants Article Analysis of the Interaction between Pisum sativum L. and Rhizobium laguerreae Strains Nodulating This Legume in Northwest Spain 1, 1 1, 2 José David Flores-Félix y , Lorena Carro , Eugenia Cerda-Castillo z, Andrea Squartini , Raúl Rivas 1,3,4 and Encarna Velázquez 1,3,4,* 1 Departamento de Microbiologíay Genética, Universidad de Salamanca, 37007 Salamanca, Spain; jdfl[email protected] (J.D.F.-F.); [email protected] (L.C.); [email protected] (E.C.-C.); [email protected] (R.R.) 2 Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, 35020 Legnaro, Italy; [email protected] 3 Instituto Hispanoluso de Investigaciones Agrarias, 37007 Salamanca, Spain 4 Unidad Asociada USAL-IRNASA, 37007 Salamanca, Spain * Correspondence: [email protected]; Tel.: +349-2329-4532 Present address: CICS-UBI–Health Sciences Research Centre, University of Beira Interior, y 6200-506 Covilhã, Portugal. Present address: Departamento de Biología, Facultad de Ciencia y Tecnología, Universidad Nacional z Autónoma de Nicaragua, León 21000, Nicaragua. Received: 3 November 2020; Accepted: 9 December 2020; Published: 11 December 2020 Abstract: Pisum sativum L. (pea) is one of the most cultivated grain legumes in European countries due to the high protein content of its seeds. Nevertheless, the rhizobial microsymbionts of this legume have been scarcely studied in these countries. In this work, we analyzed the rhizobial strains nodulating the pea in a region from Northwestern Spain, where this legume is widely cultivated. The isolated strains were genetically diverse, and the phylogenetic analysis of core and symbiotic genes showed that these strains belong to different clusters related to R.
  • Influence of Rhizobia Inoculation on Biomass Gain and Tissue Nitrogen Content of Leucaena Leucocephala Seedlings Under Drought

    Influence of Rhizobia Inoculation on Biomass Gain and Tissue Nitrogen Content of Leucaena Leucocephala Seedlings Under Drought

    Forests 2015, 6, 3686-3703; doi:10.3390/f6103686 OPEN ACCESS forests ISSN 1999-4907 www.mdpi.com/journal/forests Article Influence of Rhizobia Inoculation on Biomass Gain and Tissue Nitrogen Content of Leucaena leucocephala Seedlings under Drought Gabriela Pereyra 1,*, Henrik Hartmann 1, Beate Michalzik 2, Waldemar Ziegler 1 and Susan Trumbore 1 1 Max Planck Institute for Biogeochemistry, Hans-Knöll-str. 10, 07745 Jena, Germany; E-Mails: [email protected] (H.H.); [email protected] (W.Z.); [email protected] (S.T.) 2 Institute of Geography, Faculty of Chemical and Earth Sciences, Friedrich-Schiller-Universität Jena, Löbdergraben 32, 07743 Jena, Germany; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +49-3641-576176. Academic Editors: Reynaldo Campos Santana and Eric J. Jokela Received: 25 June 2015 / Accepted: 10 October 2015 / Published: 15 October 2015 Abstract: Anticipated increases in the frequency of heat waves and drought spells may have negative effects on the ability of leguminous trees to fix nitrogen (N). In seedlings of Leucaena leucocephala inoculated with Mesorhizobium loti or Rhizobium tropici, we investigated how the developmental stage and a short drought influenced overall biomass and the accumulation of carbon and N in plant tissues. In early developmental stages, the number of nodules and nodule biomass were correlated with total plant biomass and δ15N, and nodules and roots contributed 33%–35% of the seedling total N. Seedlings associated with R. tropici fixed more N and exhibited higher overall biomass compared with M.
  • Rhizobium Pongamiae Sp. Nov. from Root Nodules of Pongamia Pinnata

    Rhizobium Pongamiae Sp. Nov. from Root Nodules of Pongamia Pinnata

    Hindawi Publishing Corporation BioMed Research International Volume 2013, Article ID 165198, 9 pages http://dx.doi.org/10.1155/2013/165198 Research Article Rhizobium pongamiae sp. nov. from Root Nodules of Pongamia pinnata Vigya Kesari, Aadi Moolam Ramesh, and Latha Rangan Department of Biotechnology, Indian Institute of Technology Guwahati, Assam 781 039, India Correspondence should be addressed to Latha Rangan; latha [email protected] Received 27 April 2013; Accepted 6 June 2013 Academic Editor: Eldon R. Rene Copyright © 2013 Vigya Kesari et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pongamia pinnata has an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, ∘ rod-shaped, bacterial strain VKLR-01T wasisolatedfromrootnodulesofPongamia that grew optimal at 28 C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated T T temperatures and alkalinity. Strain VKLR-01 hasthemajorcellularfattyacidasC18:1 7c (65.92%). Strain VKLR-01 was found to be a nitrogen fixer using the acetylene reduction assay and PCR detection ofa nif H gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA, recA, and atpD gene sequences, G + C content, DNA-DNA hybridization etc.), strain VKLR-01T = (MTCC 10513T =MSCL1015T) is considered to represent a novel species of the genus Rhizobium for which the name Rhizobium pongamiae sp.
  • 2010.-Hungria-MLI.Pdf

    2010.-Hungria-MLI.Pdf

    Mohammad Saghir Khan l Almas Zaidi Javed Musarrat Editors Microbes for Legume Improvement SpringerWienNewYork Editors Dr. Mohammad Saghir Khan Dr. Almas Zaidi Aligarh Muslim University Aligarh Muslim University Fac. Agricultural Sciences Fac. Agricultural Sciences Dept. Agricultural Microbiology Dept. Agricultural Microbiology 202002 Aligarh 202002 Aligarh India India [email protected] [email protected] Prof. Dr. Javed Musarrat Aligarh Muslim University Fac. Agricultural Sciences Dept. Agricultural Microbiology 202002 Aligarh India [email protected] This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks. Product Liability: The publisher can give no guarantee for all the information contained in this book. The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. # 2010 Springer-Verlag/Wien Printed in Germany SpringerWienNewYork is a part of Springer Science+Business Media springer.at Typesetting: SPI, Pondicherry, India Printed on acid-free and chlorine-free bleached paper SPIN: 12711161 With 23 (partly coloured) Figures Library of Congress Control Number: 2010931546 ISBN 978-3-211-99752-9 e-ISBN 978-3-211-99753-6 DOI 10.1007/978-3-211-99753-6 SpringerWienNewYork Preface The farmer folks around the world are facing acute problems in providing plants with required nutrients due to inadequate supply of raw materials, poor storage quality, indiscriminate uses and unaffordable hike in the costs of synthetic chemical fertilizers.
  • Significance of Plant Growth Promoting Rhizobacteria in Grain Legumes

    Significance of Plant Growth Promoting Rhizobacteria in Grain Legumes

    plants Review Significance of Plant Growth Promoting Rhizobacteria in Grain Legumes: Growth Promotion and Crop Production Karivaradharajan Swarnalakshmi 1,* , Vandana Yadav 1, Deepti Tyagi 1, Dolly Wattal Dhar 1, Annapurna Kannepalli 1 and Shiv Kumar 2,* 1 Division of Microbiology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India; [email protected] (V.Y.); [email protected] (D.T.); [email protected] (D.W.D.); [email protected] (A.K.) 2 International Centre for Agricultural Research in the Dry Areas (ICARDA), Rabat 10112, Morocco * Correspondence: [email protected] (K.S.); [email protected] (S.K.) Received: 23 September 2020; Accepted: 28 October 2020; Published: 17 November 2020 Abstract: Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function of PGPRs and plant response. In this review, we provide an overview of various growth promoting mechanisms of PGPR inoculations in the production of leguminous crops.
  • Analysis of Rhizobial Strains Nodulating Phaseolus Vulgaris From

    Analysis of Rhizobial Strains Nodulating Phaseolus Vulgaris From

    Systematic and Applied Microbiology 37 (2014) 149–156 Contents lists available at ScienceDirect Systematic and Applied Microbiology j ournal homepage: www.elsevier.de/syapm Analysis of rhizobial strains nodulating Phaseolus vulgaris from Hispaniola Island, a geographic bridge between Meso and South America and the first historical link with Europe a b,c d César-Antonio Díaz-Alcántara , Martha-Helena Ramírez-Bahena , Daniel Mulas , e b b,c e,∗ Paula García-Fraile , Alicia Gómez-Moriano , Alvaro Peix , Encarna Velázquez , d Fernando González-Andrés a Facultad de Ciencias Agronómicas y Veterinarias, Universidad Autónoma de Santo Domingo, Dominican Republic b Instituto de Recursos Naturales y Agrobiología, IRNASA (CSIC), Salamanca, Spain c Unidad Asociada Grupo de Interacción Planta-Microorganismo, Universidad de Salamanca-IRNASA (CSIC), Spain d Instituto de Medio Ambiente, Recursos Naturales y Biodiversidad, Universidad de León, Spain e Departamento de Microbiología y Genética, Universidad de Salamanca, Spain a r t i c l e i n f o a b s t r a c t Article history: Hispaniola Island was the first stopover in the travels of Columbus between America and Spain, and Received 13 July 2013 played a crucial role in the exchange of Phaseolus vulgaris seeds and their endosymbionts. The analysis of Received in revised form recA and atpD genes from strains nodulating this legume in coastal and inner regions of Hispaniola Island 15 September 2013 showed that they were almost identical to those of the American strains CIAT 652, Ch24-10 and CNPAF512, Accepted 18 September 2013 which were initially named as Rhizobium etli and have been recently reclassified into Rhizobium phaseoli after the analysis of their genomes.
  • Horizontal Transfer of Symbiosis Genes Within and Between Rhizobial Genera: Occurrence and Importance

    Horizontal Transfer of Symbiosis Genes Within and Between Rhizobial Genera: Occurrence and Importance

    G C A T T A C G G C A T genes Review Horizontal Transfer of Symbiosis Genes within and Between Rhizobial Genera: Occurrence and Importance Mitchell Andrews 1,*, Sofie De Meyer 2,3 ID , Euan K. James 4 ID , Tomasz St˛epkowski 5, Simon Hodge 1 ID , Marcelo F. Simon 6 ID and J. Peter W. Young 7 ID 1 Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 84, Lincoln 7647, New Zealand; [email protected] 2 Centre for Rhizobium Studies, Murdoch University, Murdoch 6150, Australia; [email protected] 3 Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium 4 James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; [email protected] 5 Autonomous Department of Microbial Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences (SGGW), 02-776 Warsaw, Poland; [email protected] 6 Embrapa Genetic Resources and Biotechnology, Brasilia DF 70770-917, Brazil; [email protected] 7 Department of Biology, University of York, York YO10 5DD, UK; [email protected] * Correspondence: [email protected]; Tel.: +64-3-423-0692 Received: 6 May 2018; Accepted: 21 June 2018; Published: 27 June 2018 Abstract: Rhizobial symbiosis genes are often carried on symbiotic islands or plasmids that can be transferred (horizontal transfer) between different bacterial species. Symbiosis genes involved in horizontal transfer have different phylogenies with respect to the core genome of their ‘host’. Here, the literature on legume–rhizobium symbioses in field soils was reviewed, and cases of phylogenetic incongruence between rhizobium core and symbiosis genes were collated.
  • Reclassification of Rhizobium Tropici Type a Strains As Rhizobium Leucaenae Sp

    Reclassification of Rhizobium Tropici Type a Strains As Rhizobium Leucaenae Sp

    International Journal of Systematic and Evolutionary Microbiology (2012), 62, 1179–1184 DOI 10.1099/ijs.0.032912-0 Reclassification of Rhizobium tropici type A strains as Rhizobium leucaenae sp. nov. Renan Augusto Ribeiro,1,23 Marco A. Rogel,33 Aline Lo´pez-Lo´pez,3 Ernesto Ormen˜o-Orrillo,1 Fernando Gomes Barcellos,4 Julio Martı´nez,3 Fabiano Lopes Thompson,5 Esperanza Martı´nez-Romero3 and Mariangela Hungria1 Correspondence 1Embrapa Soja, Cx. Postal 231, 86001-970, Londrina, Parana´, Brazil Ernesto Ormen˜o-Orrillo 2Universidade Estadual de Londrina, Department of Microbiology, Cx. Postal 60001, 86051-990, [email protected] Londrina, Parana´, Brazil 3Centro de Ciencias Geno´micas, Universidad Nacional Auto´noma de Me´xico, Cuernavaca, Morelos, Mexico 4Universidade Paranaense – UNIPAR, Cx. Postal 224, 87502-210, Umuarama, Parana´, Brazil 5UFRJ, Center of Health Sciences, Institute of Biology, Cx. Postal 68011, 21944-970, Rio de Janeiro, Brazil Rhizobium tropici is a well-studied legume symbiont characterized by high genetic stability of the symbiotic plasmid and tolerance to tropical environmental stresses such as high temperature and low soil pH. However, high phenetic and genetic variabilities among R. tropici strains have been largely reported, with two subgroups, designated type A and B, already defined within the species. A polyphasic study comprising multilocus sequence analysis, phenotypic and genotypic characterizations, including DNA–DNA hybridization, strongly supported the reclassification of R. tropici type A strains as a novel species. Type A strains formed a well-differentiated clade that grouped with R. tropici, Rhizobium multihospitium, Rhizobium miluonense, Rhizobium lusitanum and Rhizobium rhizogenes in the phylogenies of the 16S rRNA, recA, gltA, rpoA, glnII and rpoB genes.