1
|
Santangeli M, Steininger-Mairinger T, Vetterlein D, Hann S, Oburger E. Maize (Zea mays L.) root exudation profiles change in quality and quantity during plant development - A field study. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 338:111896. [PMID: 37838155 DOI: 10.1016/j.plantsci.2023.111896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/02/2023] [Accepted: 10/10/2023] [Indexed: 10/16/2023]
Abstract
Deciphering root exudate composition of soil-grown plants is considered a crucial step to better understand plant-soil-microbe interactions affecting plant growth performance. In this study, two genotypes of Zea mays L. (WT, rth3) differing in root hair elongation were grown in the field in two substrates (sand, loam) in custom-made, perforated columns inserted into the field plots. Root exudates were collected at different plant developmental stages (BBCH 14, 19, 59, 83) using a soil-hydroponic-hybrid exudation sampling approach. Exudates were characterized by LC-MS based non-targeted metabolomics, as well as by photometric assays targeting total dissolved organic carbon, soluble carbohydrates, proteins, amino acids, and phenolics. Results showed that plant developmental stage was the main driver shaping both the composition and quantity of exuded compounds. Carbon (C) exudation per plant increased with increasing biomass production over time, while C exudation rate per cm² root surface area h-1 decreased with plant maturity. Furthermore, exudation rates were higher in the substrate with lower nutrient mobility (i.e., loam). Surprisingly, we observed higher exudation rates in the root hairless rth3 mutant compared to the root hair-forming WT sibling, though exudate metabolite composition remained similar. Our results highlight the impact of plant developmental stage on the plant-soil-microbe interplay.
Collapse
Affiliation(s)
- Michael Santangeli
- University of Natural Resources and Life Sciences, Vienna, Department of Forest and Soil Science, Institute of Soil Research, 3430 Tulln an der Donau, Austria; University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, 1190 Vienna, Austria
| | - Teresa Steininger-Mairinger
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, 1190 Vienna, Austria
| | - Doris Vetterlein
- Department of Soil System Science, UFZ, 06120 Halle/Saale, Germany; Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany
| | - Stephan Hann
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, 1190 Vienna, Austria
| | - Eva Oburger
- University of Natural Resources and Life Sciences, Vienna, Department of Forest and Soil Science, Institute of Soil Research, 3430 Tulln an der Donau, Austria.
| |
Collapse
|
2
|
Park I, Seo YS, Mannaa M. Recruitment of the rhizo-microbiome army: assembly determinants and engineering of the rhizosphere microbiome as a key to unlocking plant potential. Front Microbiol 2023; 14:1163832. [PMID: 37213524 PMCID: PMC10196466 DOI: 10.3389/fmicb.2023.1163832] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/11/2023] [Indexed: 05/23/2023] Open
Abstract
The viable community of microorganisms in the rhizosphere significantly impacts the physiological development and vitality of plants. The assembly and functional capacity of the rhizosphere microbiome are greatly influenced by various factors within the rhizosphere. The primary factors are the host plant genotype, developmental stage and status, soil properties, and resident microbiota. These factors drive the composition, dynamics, and activity of the rhizosphere microbiome. This review addresses the intricate interplay between these factors and how it facilitates the recruitment of specific microbes by the host plant to support plant growth and resilience under stress. This review also explores current methods for engineering and manipulating the rhizosphere microbiome, including host plant-mediated manipulation, soil-related methods, and microbe-mediated methods. Advanced techniques to harness the plant's ability to recruit useful microbes and the promising use of rhizo-microbiome transplantation are highlighted. The goal of this review is to provide valuable insights into the current knowledge, which will facilitate the development of cutting-edge strategies for manipulating the rhizosphere microbiome for enhanced plant growth and stress tolerance. The article also indicates promising avenues for future research in this field.
Collapse
Affiliation(s)
- Inmyoung Park
- School of Food and Culinary Arts, Youngsan University, Busan, Republic of Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
- *Correspondence: Young-Su Seo
| | - Mohamed Mannaa
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
- Department of Plant Pathology, Faculty of Agriculture, Cairo University, Giza, Egypt
- Mohamed Mannaa
| |
Collapse
|
3
|
Huang L, Li Y, Yuan J, Wan S, Colinas C, He X, Shi X, Wang Y, Yu F. Tuber indicum and T. lijiangense colonization differentially regulates plant physiological responses and mycorrhizosphere bacterial community of Castanopsis rockii seedlings. FRONTIERS IN PLANT SCIENCE 2023; 14:1134446. [PMID: 37123847 PMCID: PMC10130384 DOI: 10.3389/fpls.2023.1134446] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
Black truffles and white truffles are widely studied around the world, but their effects on plant growth and physiological responses, and on the mycorrhizosphere bacterial community of the host plant remain unclear. Here, mycorrhizal colonization of Castanopsis rockii by Tuber indicum (Chinese black truffle) and T. lijiangense (Chinese white truffle), respectively, was induced in a greenhouse study, and their effects on host growth, physiological responses and mycorrhizosphere bacterial communities were compared. The results show that colonization of both Tuber species significantly increased leaf photosynthetic rate, leaf P concentration and mycorrhizosphere acid phosphatase activity, as well as richness of mycorrhizosphere bacterial communities of C. rockii seedlings. However, T. indicum colonization on the one hand significantly decreased tartrate content, bacterial acid phosphatase, phoC gene abundance in the mycorrhizosphere, and peroxidase (POD) activity of ectomycorrhizal root tips, but on the other hand increased mycorrhizosphere pH and superoxide dismutase (SOD) of ectomycorrhizal root tips, compared to T. lijiangense colonization. Moreover, principal coordinate and β-diversity analyses show significant differences in mycorrhizosphere bacterial community composition between T. indicum and T. lijiangese colonized C. rockii seedlings. Finally, the relative abundance of the bacterium Agromyces cerinus significantly correlated to mycorrhizosphere acid phosphatase activity and leaf P concentration, suggesting that this bacterium might play an important role in P mobilization and acquisition. Overall, these results suggest that T. indicum and T. lijiangense differently regulate their host plant's physiological responses and mycorrhizosphere bacterial community.
Collapse
Affiliation(s)
- Lanlan Huang
- College of Resources and Environment, Yunnan Agricultural University, Kunming, China
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yongmei Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming, China
| | - Jing Yuan
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Shanping Wan
- College of Resources and Environment, Yunnan Agricultural University, Kunming, China
| | - Carlos Colinas
- Department of Crop and Forest Science, University of Lleida, Lleida, Spain
| | - Xinhua He
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Centre of Excellence for Soil Biology, College of Resources and Environment, and Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, School of Life Sciences, Southwest University, Chongqing, China
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Xiaofei Shi
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Guizhou Kangqunyuan Biotechnology Co., LTD, Liupanshui, Guizhou, China
| | - Yanliang Wang
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- *Correspondence: Yanliang Wang, ; Fuqiang Yu,
| | - Fuqiang Yu
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- *Correspondence: Yanliang Wang, ; Fuqiang Yu,
| |
Collapse
|
4
|
Oppenheimer-Shaanan Y, Jakoby G, Starr ML, Karliner R, Eilon G, Itkin M, Malitsky S, Klein T. A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress. eLife 2022; 11:79679. [PMID: 35858113 PMCID: PMC9385208 DOI: 10.7554/elife.79679] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/17/2022] [Indexed: 12/04/2022] Open
Abstract
Root exudates are thought to play an important role in plant-microbial interactions. In return for nutrition, soil bacteria can increase the bioavailability of soil nutrients. However, root exudates typically decrease in situations such as drought, calling into question the efficacy of solvation and bacteria-dependent mineral uptake in such stress. Here, we tested the hypothesis of exudate-driven microbial priming on Cupressus saplings grown in forest soil in custom-made rhizotron boxes. A 1-month imposed drought and concomitant inoculations with a mix of Bacillus subtilis and Pseudomonas stutzeri, bacteria species isolated from the forest soil, were applied using factorial design. Direct bacteria counts and visualization by confocal microscopy showed that both bacteria associated with Cupressus roots. Interestingly, root exudation rates increased 2.3-fold with bacteria under drought, as well as irrigation. Forty-four metabolites in exudates were significantly different in concentration between irrigated and drought trees, including phenolic acid compounds and quinate. When adding these metabolites as carbon and nitrogen sources to bacterial cultures of both bacterial species, eight of nine metabolites stimulated bacterial growth. Importantly, soil phosphorous bioavailability was maintained only in inoculated trees, mitigating drought-induced decrease in leaf phosphorus and iron. Our observations of increased root exudation rate when drought and inoculation regimes were combined support the idea of root recruitment of beneficial bacteria, especially under water stress. The soil surrounding the roots of trees, termed the rhizosphere, is full of bacteria and other communities of microorganisms. Trees secrete organic compounds in to the soil which are thought to influence the behavior of bacteria in the rhizosphere. Specifically, these root secretions, or ‘exudates’, attract and feed soil bacteria, which, in return, release nutrients that benefit the tree. In 2020, a group of researchers found that some trees in the Mediterranean forest produce more exudates during the long dry season. This suggests that the compounds secreted by roots may help trees to tolerate stress conditions, such as drought. To test this hypothesis, Oppenheimer-Shaanan et al. – including some of the researchers involved in the 2020 study – grew young Cupressus sempervirens conifer trees in drought conditions that starved them of the nutrients phosphorous and iron. Each tree was planted in a custom-built box which allowed easy access to roots growing in the soil. Two species of bacteria from the forest soil C. sempervirens trees naturally live in were then added to the soil in each box. Microscopy revealed that both species of bacteria, which had been tagged with fluorescent markers, were attracted to the roots of the trees, boosting the bacterial community in the rhizosphere. Oppenheimer-Shaanan et al. found that the recruitment of the two bacterial species caused the rate at which exudates were secreted from the roots to increase. Compounds in the exudate stimulated the bacteria to grow. Ultimately, levels of phosphorous and iron in the leaves of the starved trees increased when in the presence of these soil bacteria. This suggests that bacteria in the rhizosphere helps trees to survive when they are under stress and have low levels of water. These findings provide further evidence that plants and bacteria can live together in symbiosis and benefit one another. This could have important implications for forest ecology and potentially how trees are grown in orchards and gardens. For example, specific bacteria and organic compounds in the rhizosphere may be able to improve tree health. However, further work is needed to investigate whether the exudate compounds identified in this study are found more widely in nature.
Collapse
Affiliation(s)
| | - Gilad Jakoby
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Maya L Starr
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Romiel Karliner
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Gal Eilon
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Maxim Itkin
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Malitsky
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
5
|
Wang L, Rengel Z, Zhang K, Jin K, Lyu Y, Zhang L, Cheng L, Zhang F, Shen J. Ensuring future food security and resource sustainability: insights into the rhizosphere. iScience 2022; 25:104168. [PMID: 35434553 PMCID: PMC9010633 DOI: 10.1016/j.isci.2022.104168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Feeding the world’s growing population requires continuously increasing crop yields with less fertilizers and agrochemicals on limited land. Focusing on plant belowground traits, especially root-soil-microbe interactions, holds a great promise for overcoming this challenge. The belowground root-soil-microbe interactions are complex and involve a range of physical, chemical, and biological processes that influence nutrient-use efficiency, plant growth and health. Understanding, predicting, and manipulating these rhizosphere processes will enable us to harness the relevant interactions to improve plant productivity and nutrient-use efficiency. Here, we review the recent progress and challenges in root-soil-microbe interactions. We also highlight how root-soil-microbe interactions could be manipulated to ensure food security and resource sustainability in a changing global climate, with an emphasis on reducing our dependence on fertilizers and agrochemicals.
Collapse
Affiliation(s)
- Liyang Wang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Zed Rengel
- Soil Science & Plant Nutrition, UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia.,Institute for Adriatic Crops and Karst Reclamation, Split 21000, Croatia
| | - Kai Zhang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Kemo Jin
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Yang Lyu
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Lin Zhang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Lingyun Cheng
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Fusuo Zhang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| | - Jianbo Shen
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, PR China
| |
Collapse
|
6
|
Dallstream C, Weemstra M, Soper FM. A framework for fine‐root trait syndromes: syndrome coexistence may support phosphorus partitioning in tropical forests. OIKOS 2022. [DOI: 10.1111/oik.08908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Monique Weemstra
- Ecology and Evolutionary Biology, Univ. of Michigan Ann Arbor MI USA
| | | |
Collapse
|
7
|
Freschet GT, Pagès L, Iversen CM, Comas LH, Rewald B, Roumet C, Klimešová J, Zadworny M, Poorter H, Postma JA, Adams TS, Bagniewska‐Zadworna A, Bengough AG, Blancaflor EB, Brunner I, Cornelissen JHC, Garnier E, Gessler A, Hobbie SE, Meier IC, Mommer L, Picon‐Cochard C, Rose L, Ryser P, Scherer‐Lorenzen M, Soudzilovskaia NA, Stokes A, Sun T, Valverde‐Barrantes OJ, Weemstra M, Weigelt A, Wurzburger N, York LM, Batterman SA, Gomes de Moraes M, Janeček Š, Lambers H, Salmon V, Tharayil N, McCormack ML. A starting guide to root ecology: strengthening ecological concepts and standardising root classification, sampling, processing and trait measurements. THE NEW PHYTOLOGIST 2021; 232:973-1122. [PMID: 34608637 PMCID: PMC8518129 DOI: 10.1111/nph.17572] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/22/2021] [Indexed: 05/17/2023]
Abstract
In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in this broader guide to root ecology, including sections I-VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers' views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning.
Collapse
Affiliation(s)
- Grégoire T. Freschet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
| | - Loïc Pagès
- UR 1115 PSHCentre PACA, site AgroparcINRAE84914Avignon cedex 9France
| | - Colleen M. Iversen
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Louise H. Comas
- USDA‐ARS Water Management Research Unit2150 Centre Avenue, Bldg D, Suite 320Fort CollinsCO80526USA
| | - Boris Rewald
- Department of Forest and Soil SciencesUniversity of Natural Resources and Life SciencesVienna1190Austria
| | - Catherine Roumet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Jitka Klimešová
- Department of Functional EcologyInstitute of Botany CASDukelska 13537901TrebonCzech Republic
| | - Marcin Zadworny
- Institute of DendrologyPolish Academy of SciencesParkowa 562‐035KórnikPoland
| | - Hendrik Poorter
- Plant Sciences (IBG‐2)Forschungszentrum Jülich GmbHD‐52425JülichGermany
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | | | - Thomas S. Adams
- Department of Plant SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Agnieszka Bagniewska‐Zadworna
- Department of General BotanyInstitute of Experimental BiologyFaculty of BiologyAdam Mickiewicz UniversityUniwersytetu Poznańskiego 661-614PoznańPoland
| | - A. Glyn Bengough
- The James Hutton InstituteInvergowrie, Dundee,DD2 5DAUK
- School of Science and EngineeringUniversity of DundeeDundee,DD1 4HNUK
| | | | - Ivano Brunner
- Forest Soils and BiogeochemistrySwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
| | - Johannes H. C. Cornelissen
- Department of Ecological ScienceFaculty of ScienceVrije Universiteit AmsterdamDe Boelelaan 1085Amsterdam1081 HVthe Netherlands
| | - Eric Garnier
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Arthur Gessler
- Forest DynamicsSwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsETH Zurich8092ZurichSwitzerland
| | - Sarah E. Hobbie
- Department of Ecology, Evolution and BehaviorUniversity of MinnesotaSt PaulMN55108USA
| | - Ina C. Meier
- Functional Forest EcologyUniversity of HamburgHaidkrugsweg 122885BarsbütelGermany
| | - Liesje Mommer
- Plant Ecology and Nature Conservation GroupDepartment of Environmental SciencesWageningen University and ResearchPO Box 476700 AAWageningenthe Netherlands
| | | | - Laura Rose
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
- Senckenberg Biodiversity and Climate Research Centre (BiK-F)Senckenberganlage 2560325Frankfurt am MainGermany
| | - Peter Ryser
- Laurentian University935 Ramsey Lake RoadSudburyONP3E 2C6Canada
| | | | - Nadejda A. Soudzilovskaia
- Environmental Biology DepartmentInstitute of Environmental SciencesCMLLeiden UniversityLeiden2300 RAthe Netherlands
| | - Alexia Stokes
- INRAEAMAPCIRAD, IRDCNRSUniversity of MontpellierMontpellier34000France
| | - Tao Sun
- Institute of Applied EcologyChinese Academy of SciencesShenyang110016China
| | - Oscar J. Valverde‐Barrantes
- International Center for Tropical BotanyDepartment of Biological SciencesFlorida International UniversityMiamiFL33199USA
| | - Monique Weemstra
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Alexandra Weigelt
- Systematic Botany and Functional BiodiversityInstitute of BiologyLeipzig UniversityJohannisallee 21-23Leipzig04103Germany
| | - Nina Wurzburger
- Odum School of EcologyUniversity of Georgia140 E. Green StreetAthensGA30602USA
| | - Larry M. York
- Biosciences Division and Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Sarah A. Batterman
- School of Geography and Priestley International Centre for ClimateUniversity of LeedsLeedsLS2 9JTUK
- Cary Institute of Ecosystem StudiesMillbrookNY12545USA
| | - Moemy Gomes de Moraes
- Department of BotanyInstitute of Biological SciencesFederal University of Goiás1974690-900Goiânia, GoiásBrazil
| | - Štěpán Janeček
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawley (Perth)WA 6009Australia
| | - Hans Lambers
- School of Biological SciencesThe University of Western AustraliaCrawley (Perth)WAAustralia
| | - Verity Salmon
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Nishanth Tharayil
- Department of Plant and Environmental SciencesClemson UniversityClemsonSC29634USA
| | - M. Luke McCormack
- Center for Tree ScienceMorton Arboretum, 4100 Illinois Rt. 53LisleIL60532USA
| |
Collapse
|
8
|
Tiziani R, Puschenreiter M, Smolders E, Mimmo T, Herrera JC, Cesco S, Santner J. Millimetre-resolution mapping of citrate exuded from soil-grown roots using a novel, low-invasive sampling technique. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3513-3525. [PMID: 33744951 DOI: 10.1093/jxb/erab123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The reliable sampling of root exudates in soil-grown plants is experimentally challenging. This study aimed at developing a citrate sampling and mapping technique with millimetre-resolution using DGT (diffusive gradients in thin films) ZrOH-binding gels. Citrate adsorption kinetics, DGT capacity, and stability of ZrOH gels were evaluated. ZrOH gels were applied to generate 2D maps of citrate exuded by white lupin roots grown in a rhizotron in a phosphorus-deficient soil. Citrate was adsorbed quantitatively and rapidly by the ZrOH gels; these gels can be stored after sampling for several weeks prior to analysis. The DGT capacity of the ZrOH gel for citrate depends on the ionic strength and the pH of the soil solution, but was suitable for citrate sampling. We generated for the first time 2D citrate maps of rhizotron-grown plants at a millimetre resolution to measure an illustrated plant response to phosphorus fertilization, demonstrating that DGT-based citrate sampling is suitable for studying root exudation in soil environments, at high spatial resolution. The change of binding material would also allow sampling of other exudate classes and exudation profiles of entire root systems. These aspects are crucial in cultivar breeding and selection.
Collapse
Affiliation(s)
- Raphael Tiziani
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy
- Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Life Science, Vienna, Austria
| | - Markus Puschenreiter
- Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Life Science, Vienna, Austria
| | - Erik Smolders
- Division of Soil and Water Management, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Tanja Mimmo
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy
| | - José Carlos Herrera
- Institute of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Science, Vienna, Austria
| | - Stefano Cesco
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Jakob Santner
- Institute of Agronomy, Department of Crop Sciences, University of Natural Resources and Life Science, Vienna, Austria
| |
Collapse
|
9
|
Sun L, Ataka M, Han M, Han Y, Gan D, Xu T, Guo Y, Zhu B. Root exudation as a major competitive fine-root functional trait of 18 coexisting species in a subtropical forest. THE NEW PHYTOLOGIST 2021; 229:259-271. [PMID: 32772392 DOI: 10.1111/nph.16865] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Root exudation stimulates microbial decomposition and enhances nutrient availability to plants. It remains difficult to measure and predict this carbon flux in natural conditions, especially for mature woody plants. Based on a known conceptual framework of root functional traits coordination, we proposed that root functional traits may predict root exudation. We measured root exudation and other seven root morphological/chemical/physiological traits for 18 coexisting woody species in a deciduous-evergreen mixed forest in subtropical China. Root exudation, respiration, diameter and nitrogen (N) concentration all exhibited significant phylogenetic signals. We found that root exudation positively correlated with competitive traits (root respiration, N concentration) and negatively with a conservative trait (root tissue density). Furthermore, these relationships were independent of phylogenetic signals. A principal component analysis showed that root exudation and morphological traits loaded on two perpendicular axes. Root exudation is a competitive trait in a multidimensional fine-root functional coordination. The metabolic dimension on which root exudation loaded was relatively independent of the morphological dimension, indicating that increasing nutrient availability by root exudation might be a complementary strategy for plant nutrient acquisition. The positive relationship between root exudation and root respiration and N concentration is a promising approach for the future prediction of root exudation.
Collapse
Affiliation(s)
- Lijuan Sun
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Mioko Ataka
- Graduate School of Agriculture, Kyoto University, Kyoto, 6068502, Japan
| | - Mengguang Han
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yunfeng Han
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Dayong Gan
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Tianle Xu
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yanpei Guo
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Biao Zhu
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| |
Collapse
|
10
|
Jakoby G, Rog I, Megidish S, Klein T. Enhanced root exudation of mature broadleaf and conifer trees in a Mediterranean forest during the dry season. TREE PHYSIOLOGY 2020; 40:1595-1605. [PMID: 32705136 DOI: 10.1093/treephys/tpaa092] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/19/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Root exudates are part of the rhizodeposition process, which is the major source of soil organic carbon (C) released by plant roots. This flux of C is believed to have profound effects on C and nutrient cycling in ecosystems. The quantity of root exudates depends on the plant species, the period throughout the year, and external biotic and abiotic factors. Since root exudates of mature trees are difficult to collect in field conditions, very little is known about their flux, especially in water-limited ecosystems, such as the seasonally hot and dry Mediterranean maquis. Here, we collected exudates from DNA-identified roots in the forest from the gymnosperm Cupressus sempervirens L. and the evergreen angiosperm Pistacia lentiscus L. by 48-h incubations on a monthly temporal resolution throughout the year. We examined relationships of the root exudate C flux to abiotic parameters of the soil (water content, water potential, temperature) and atmosphere (vapor pressure deficit, temperature). We also studied relationships to C fluxes through the leaves as indicators of tree C balance. Root exudation rates varied significantly along the year, increasing from 6 μg C cm -2 root day-1 in both species in the wet season to 4- and 11-fold rates in Pistacia and Cupressus, respectively, in the dry season. A stepwise linear mixed-effects model showed that the three soil parameters were the most influential on exudation rates. Among biotic factors, there was a significant negative correlation of exudation rate with leaf assimilation in Cupressus and a significant negative correlation with leaf respiration in Pistacia. Our observation of enhanced exudation flux during the dry season indicates that exudation dynamics in the field are less sensitive to the low tree C availability in the dry season. The two key Mediterranean forest species seem to respond to seasonal changes in the rhizosphere such as drying and warming, and therefore invest C in the rhizosphere under seasonal drought.
Collapse
Affiliation(s)
- Gilad Jakoby
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ido Rog
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shacham Megidish
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
11
|
Bacterial Diversity in the Rhizosphere of Anabasis aphylla in the Gurbantunggut Desert, China. Curr Microbiol 2020; 77:3750-3759. [PMID: 32939639 DOI: 10.1007/s00284-020-02177-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 08/21/2020] [Indexed: 10/23/2022]
Abstract
Bacteria are the most abundant soil microbes and are sensitive to environmental change, especially soil carbon (C) and nitrogen (N) dynamics. The bacterial diversity of rhizosphere and bulk soils associated with desert plants is not well understood. In this study, we measured the properties of rhizosphere and bulk soils at different depths (0-20, 20-40, 40-60, and 60-80 cm), the diversity of bacterial communities (16S rDNA amplicon sequencing), and their relationships with Anabasis aphylla in the southern margin of the Gurbantunggut Desert, Junggar Basin, China. A total of 11,420 operational taxonomic units (OTUs) were obtained from 40 soil samples, belonging to 641 genera, 269 families, 137 orders, 61 classes, and 44 phyla. There were significant differences in electrical conductivity (EC), available nitrogen (AN), available phosphorus (AP), available potassium (AK), and bacterial diversity. The dominant bacterial communities of the rhizosphere and bulk soils at the phylum level were Actinobacteria, Proteobacteria, and Bacteroidetes. At the genus level, the dominant communities of the rhizosphere and bulk soils were Halomonas and Glycomyces, respectively. At different soil depths, the abundances of bacteria in the soil were 10.2% (0-20 cm) > 8.4% (20-40 cm) > 8.3% (60-80 cm) > 6.2% (40-60 cm). Our results indicate that bacteria in the phyla Actinobacteria and Proteobacteria, as well as the genus Halomonas, are key to the drought and salt tolerance of A. aphylla.
Collapse
|
12
|
Akatsuki M, Makita N. Influence of fine root traits on in situ exudation rates in four conifers from different mycorrhizal associations. TREE PHYSIOLOGY 2020; 40:1071-1079. [PMID: 32333786 DOI: 10.1093/treephys/tpaa051] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 03/15/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Plant roots can exude organic compounds into the soil that are useful for plant survival because they can degrade microorganisms around the roots and enhance allelopathy against other plant invasions. We developed a method to collect carbon (C) exudation on a small scale from tree fine roots by C-free filter traps. We quantified total C through root exudation in four conifers from different microbial symbiotic groups (ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM)) in a cool-temperate forest in Japan. We determined the relationship of mass-based exudation rate from three diameter classes (<0.5, 0.5-1.0, and 1.0-2.5 mm) of the intact root system with root traits such as morphological traits including root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD) and chemical traits including root nitrogen (N) content and C/N. Across species, the mass-based root exudation rate was found to correlate with diameter, SRA, RTD, N and C/N. When comparing mycorrhizal types, there were significant relationships between the exudation and diameter, SRL, SRA, root N and C/N in ECM species; however, these were not significant in AM species. Our results show that relationships between in situ root exudation and every measured trait of morphology and chemistry were strongly driven by ECM roots and not by AM roots. These differences might explain the fact that ECM roots in this study potentially covaried by optimizing the exudation and root morphology in forest trees, while exudation in AM roots did not change with changes in root morphology. In addition, the contrasting results may be attributable to the effect of degree and position of ECM and AM colonization in fine root system. Differences in fine root exudation relationships to root morphology for the two types of mycorrhizae will help us better understand the underlying mechanisms of belowground C allocation in forest ecosystems.
Collapse
Affiliation(s)
- Maiko Akatsuki
- Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Naoki Makita
- Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| |
Collapse
|
13
|
Kumar A, Dubey A. Rhizosphere microbiome: Engineering bacterial competitiveness for enhancing crop production. J Adv Res 2020; 24:337-352. [PMID: 32461810 PMCID: PMC7240055 DOI: 10.1016/j.jare.2020.04.014] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/15/2020] [Accepted: 04/25/2020] [Indexed: 12/29/2022] Open
Abstract
Plants in nature are constantly exposed to a variety of abiotic and biotic stresses which limits their growth and production. Enhancing crop yield and production to feed exponentially growing global population in a sustainable manner by reduced chemical fertilization and agrochemicals will be a big challenge. Recently, the targeted application of beneficial plant microbiome and their cocktails to counteract abiotic and biotic stress is gaining momentum and becomes an exciting frontier of research. Advances in next generation sequencing (NGS) platform, gene editing technologies, metagenomics and bioinformatics approaches allows us to unravel the entangled webs of interactions of holobionts and core microbiomes for efficiently deploying the microbiome to increase crops nutrient acquisition and resistance to abiotic and biotic stress. In this review, we focused on shaping rhizosphere microbiome of susceptible host plant from resistant plant which comprises of specific type of microbial community with multiple potential benefits and targeted CRISPR/Cas9 based strategies for the manipulation of susceptibility genes in crop plants for improving plant health. This review is significant in providing first-hand information to improve fundamental understanding of the process which helps in shaping rhizosphere microbiome.
Collapse
Affiliation(s)
- Ashwani Kumar
- Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, M.P., India
| | - Anamika Dubey
- Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, M.P., India
| |
Collapse
|
14
|
Bettenfeld P, Fontaine F, Trouvelot S, Fernandez O, Courty PE. Woody Plant Declines. What's Wrong with the Microbiome? TRENDS IN PLANT SCIENCE 2020; 25:381-394. [PMID: 31983620 DOI: 10.1016/j.tplants.2019.12.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Woody plant (WP) declines have multifactorial determinants as well as a biological and economic reality. The vascular system of WPs involved in the transport of carbon, nitrogen, and water from sources to sinks has a seasonal activity, which places it at a central position for mediating plant-environment interactions from nutrient cycling to community assembly and for regulating a variety of processes. To limit effects and to fight against declines, we propose: (i) to consider the WP and its associated microbiota as an holobiont and as a set of functions; (ii) to consider simultaneously, without looking at what comes first, the physiological or pathogenic disorders; and (iii) to define pragmatic strategies, including preventive and curative agronomical practices based on microbiota engineering.
Collapse
Affiliation(s)
- Pauline Bettenfeld
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, Dijon, France; SFR Condorcet CNRS 3417, Université de Reims Champagne-Ardenne, Unité Résistance Induite et Bioprotection des Plantes EA4707, Reims, France
| | - Florence Fontaine
- SFR Condorcet CNRS 3417, Université de Reims Champagne-Ardenne, Unité Résistance Induite et Bioprotection des Plantes EA4707, Reims, France
| | - Sophie Trouvelot
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, Dijon, France
| | - Olivier Fernandez
- SFR Condorcet CNRS 3417, Université de Reims Champagne-Ardenne, Unité Résistance Induite et Bioprotection des Plantes EA4707, Reims, France
| | - Pierre-Emmanuel Courty
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, Dijon, France.
| |
Collapse
|
15
|
Meier IC, Tückmantel T, Heitkötter J, Müller K, Preusser S, Wrobel TJ, Kandeler E, Marschner B, Leuschner C. Root exudation of mature beech forests across a nutrient availability gradient: the role of root morphology and fungal activity. THE NEW PHYTOLOGIST 2020; 226:583-594. [PMID: 31868933 DOI: 10.1111/nph.16389] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Root exudation is a key plant function with a large influence on soil organic matter dynamics and plant-soil feedbacks in forest ecosystems. Yet despite its importance, the main ecological drivers of root exudation in mature forest trees remain to be identified. During two growing seasons, we analyzed the dependence of in situ collected root exudates on root morphology, soil chemistry and nutrient availability in six mature European beech (Fagus sylvatica L.) forests on a broad range of bedrock types. Root morphology was a major driver of root exudation across the nutrient availability gradient. A doubling of specific root length exponentially increased exudation rates of mature trees by c. 5-fold. Root exudation was also closely negatively related to soil pH and nitrogen (N) availability. At acidic and N-poor sites, where fungal biomass was reduced, exudation rates were c. 3-fold higher than at N- and base-richer sites and correlated negatively with the activity of enzymes degrading less bioavailable carbon (C) and N in the bulk soil. We conclude that root exudation increases on highly acidic, N-poor soils, in which fungal activity is reduced and a greater portion of the assimilated plant C is shifted to the external ecosystem C cycle.
Collapse
Affiliation(s)
- Ina C Meier
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, 37073, Göttingen, Germany
| | - Timo Tückmantel
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, 37073, Göttingen, Germany
| | - Julian Heitkötter
- Soil Science and Soil Ecology, Institute of Geography, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Karolin Müller
- Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, 70599, Stuttgart, Germany
| | - Sebastian Preusser
- Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, 70599, Stuttgart, Germany
| | - Thomas J Wrobel
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Ellen Kandeler
- Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, 70599, Stuttgart, Germany
| | - Bernd Marschner
- Soil Science and Soil Ecology, Institute of Geography, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Christoph Leuschner
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, 37073, Göttingen, Germany
| |
Collapse
|
16
|
An Z, Guo F, Chen Y, Bai G, Chen Z. Rhizosphere bacterial and fungal communities during the growth of Angelica sinensis seedlings cultivated in an Alpine uncultivated meadow soil. PeerJ 2020; 8:e8541. [PMID: 32257632 PMCID: PMC7103203 DOI: 10.7717/peerj.8541] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Angelica sinensis seedlings are grown in alpine uncultivated meadow soil with rainfed agroecosystems to ensure the quality of A. sinensis after seedling transplantation. The aim was to investigate the rhizosphere bacterial and fungal communities during the growth stages of A. sinensis seedlings. METHODS The bacterial and fungal communities were investigated by HiSeq sequencing of 16S and 18S rDNA, respectively. RESULTS Proteobacteria and Bacteroidetes were bacterial dominant phyla throughout growth stages. Fungal dominant phyla varied with growth stages, dominant phyla Ascomycota and Chytridiomycota in AM5, dominant phyla Basidiomycota, Ascomycota and Zygomycota in BM5, and dominant phyla Basidiomycota and Ascomycota in CM5. There was no significant variation in the alpha-diversity of the bacterial and fungal communities, but significant variation was in the beta-diversity. We found that the variation of microbial community composition was accompanied by the changes in community function. The relative abundance of fungal pathogens increased with plant growth. We also identified the core microbes, significant-changing microbes, stage-specific microbes, and host-specific microbes. Plant weight, root length, root diameter, soil pH, rainfall, and climate temperature were the key divers to microbial community composition. CONCLUSIONS Our findings reported the variation and environmental drivers of rhizosphere bacterial and fungal communities during the growth of A. sinensis seedlings, which enhance the understanding of the rhizosphere microbial community in this habitat.
Collapse
Affiliation(s)
- Zhigang An
- College of Life Science and Technology, College of Agronomy, Gansu Provincial Key Lab of Good Agricultural Production for Traditional Chinese Medicine, Gansu Provincial Engineering Research Centre for Medical Plant Cultivation and Breeding, Provincial Key Lab of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
- Pharmacy Department, Gansu University of Chinese Medicine, Dingxi, China
| | - Fengxia Guo
- College of Life Science and Technology, College of Agronomy, Gansu Provincial Key Lab of Good Agricultural Production for Traditional Chinese Medicine, Gansu Provincial Engineering Research Centre for Medical Plant Cultivation and Breeding, Provincial Key Lab of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
| | - Yuan Chen
- College of Life Science and Technology, College of Agronomy, Gansu Provincial Key Lab of Good Agricultural Production for Traditional Chinese Medicine, Gansu Provincial Engineering Research Centre for Medical Plant Cultivation and Breeding, Provincial Key Lab of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
- Gansu Engineering Lab of Resource Reservation and Utilization for Characteristic Chinese Medicine, Gansu Tasly Zhongtian Pharmaceutical Co., Ltd., Dingxi, China
| | - Gang Bai
- College of Life Science and Technology, College of Agronomy, Gansu Provincial Key Lab of Good Agricultural Production for Traditional Chinese Medicine, Gansu Provincial Engineering Research Centre for Medical Plant Cultivation and Breeding, Provincial Key Lab of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
| | - Zhengjun Chen
- College of Life Science and Technology, College of Agronomy, Gansu Provincial Key Lab of Good Agricultural Production for Traditional Chinese Medicine, Gansu Provincial Engineering Research Centre for Medical Plant Cultivation and Breeding, Provincial Key Lab of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
| |
Collapse
|
17
|
Dukunde A, Schneider D, Schmidt M, Veldkamp E, Daniel R. Tree Species Shape Soil Bacterial Community Structure and Function in Temperate Deciduous Forests. Front Microbiol 2019; 10:1519. [PMID: 31338079 PMCID: PMC6629791 DOI: 10.3389/fmicb.2019.01519] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/18/2019] [Indexed: 01/23/2023] Open
Abstract
Amplicon-based analysis of 16S rRNA genes and transcripts was used to assess the effect of tree species composition on soil bacterial community structure and function in a temperate deciduous forest. Samples were collected from mono and mixed stands of Fagus sylvatica (beech), Carpinus betulus (hornbeam), Tilia sp. (lime), and Quercus sp. (oak) in spring, summer, and autumn. Soil bacterial community exhibited similar taxonomic composition at total (DNA-based) and potentially active community (RNA-based) level, with fewer taxa present at active community level. Members of Rhizobiales dominated at both total and active bacterial community level, followed by members of Acidobacteriales, Solibacterales, Rhodospirillales, and Xanthomonadales. Bacterial communities at total and active community level showed a significant positive correlation with tree species identity (mono stands) and to a lesser extent with tree species richness (mixed stands). Approximately 58 and 64% of indicator operational taxonomic units (OTUs) showed significant association with only one mono stand at total and active community level, respectively, indicating a strong impact of tree species on soil bacterial community composition. Soil C/N ratio, pH, and P content similarly exhibited a significant positive correlation with soil bacterial communities, which was attributed to direct and indirect effects of forest stands. Seasonality was the strongest driver of predicted metabolic functions related to C fixation and degradation, and N metabolism. Carbon and nitrogen metabolic processes were significantly abundant in spring, while C degradation gene abundances increased from summer to autumn, corresponding to increased litterfall and decomposition. The results revealed that in a spatially homogenous forest soil, tree species diversity and richness are dominant drivers of structure and composition in soil bacterial communities.
Collapse
Affiliation(s)
- Amélie Dukunde
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany
| | - Dominik Schneider
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany
| | - Marcus Schmidt
- Soil Science of Tropical and Subtropical Ecosystems, Faculty of Forest Sciences and Forest Ecology, Büsgen Institute, Georg-August University of Göttingen, Göttingen, Germany
| | - Edzo Veldkamp
- Soil Science of Tropical and Subtropical Ecosystems, Faculty of Forest Sciences and Forest Ecology, Büsgen Institute, Georg-August University of Göttingen, Göttingen, Germany
| | - Rolf Daniel
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany
| |
Collapse
|
18
|
Presence of Mycorrhizal Fungal Hyphae Rather than Living Roots Retards Root Litter Decomposition. FORESTS 2019. [DOI: 10.3390/f10060502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Although both living roots and mycorrhizal fungi are well known to interact with saprotrophic microbes to affect litter decomposition, their relative importance is largely unclear. Here, a two-year pot experiment was conducted with two ectomycorrhizal (Pinus elliottii and Pinus massoniana) and four arbuscular mycorrhizal (Cinnamomum camphora, Cunninghamia lanceolata, Michelia maudiae and Schima superba) subtropical tree species to evaluate the relative effects of living roots and mycorrhizal fungal hyphae on their own root litter decomposition and to test whether these effects differed between ectomycorrhizal and arbuscular mycorrhizal trees. To achieve these objectives, litterbags with 50-µm and 1-mm mesh sizes filled with root litter of a given tree species were simultaneously installed in pots planted with the same species and unplanted pots filled with composite soil for all species. Effects of living roots alone were calculated as differences in root litter decomposition between 50-µm and 1-mm mesh litterbags installed in planted pots. Mycorrhizal hyphal effects were calculated as differences in root litter decomposition between 50-µm litterbags installed in planted and unplanted pots. The presence of mycorrhizal fungal hyphae significantly reduced root litter mass loss and inhibited the activities of β-glucosidase and phenol oxidase, while effects of living roots alone were non-significant when all tree species were pooled and inconsistent at the tree species level. Mycorrhizal fungal hyphae induced decreases in root litter mass loss that were markedly related to their inhibitory effects on β-glucosidase and phenol oxidase activities. When tree species were grouped by their mycorrhizal types, non-significant differences were observed between ectomycorrhizal and arbuscular mycorrhizal trees in their living root or mycorrhizal fungal effects on root litter decomposition. These findings highlight the important roles of mycorrhizal fungi in mediating litter decomposition via interacting with saprotrophic microbes and suggest that changes in tree carbon allocation to mycorrhizal fungi owing to global change may affect soil carbon storage.
Collapse
|
19
|
Preece C, Farré-Armengol G, Llusià J, Peñuelas J. Thirsty tree roots exude more carbon. TREE PHYSIOLOGY 2018; 38:690-695. [PMID: 29304257 DOI: 10.1093/treephys/tpx163] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/16/2017] [Indexed: 05/07/2023]
Abstract
Root exudation is an important input of carbon into soils and affects plant and soil communities, but little is known about the effect of climatic factors such as drought on exudation, and its ability to recover. We studied the impact of increasing drought on root exudation and its subsequent recovery in the Mediterranean tree species Quercus ilex L. in a greenhouse study by measuring the amount of total organic carbon in exudates. The amount of exudation per unit root area increased with drought duration and was 21% higher under the most extreme drought scenario compared with the non-droughted control. The amount of root exudation did not differ between the treatments following 6 weeks of re-watering, indicating a strong capacity for recovery in this species. We concluded that drought could affect the amount of root exudation, which could in turn have a large impact on microbial activity in the rhizosphere, and alter these microbial communities, at least in the short term. This tree species may be able to return to normal levels of root exudation after a drought event, but long-term exudate-mediated impacts on Mediterranean forest soils may be an unforeseen effect of drought.
Collapse
Affiliation(s)
- Catherine Preece
- CREAF, Cerdanyola del Vallès, 08193, Spain
- CSIC Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra 08193, Spain
| | - Gerard Farré-Armengol
- CREAF, Cerdanyola del Vallès, 08193, Spain
- CSIC Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra 08193, Spain
| | - Joan Llusià
- CREAF, Cerdanyola del Vallès, 08193, Spain
- CSIC Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra 08193, Spain
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, 08193, Spain
- CSIC Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra 08193, Spain
| |
Collapse
|
20
|
Chagas FO, Pessotti RDC, Caraballo-Rodríguez AM, Pupo MT. Chemical signaling involved in plant-microbe interactions. Chem Soc Rev 2018; 47:1652-1704. [PMID: 29218336 DOI: 10.1039/c7cs00343a] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.
Collapse
Affiliation(s)
- Fernanda Oliveira Chagas
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Avenida do Café, s/n, 14040-903, Ribeirão Preto-SP, Brazil.
| | | | | | | |
Collapse
|
21
|
Liese R, Lübbe T, Albers NW, Meier IC. The mycorrhizal type governs root exudation and nitrogen uptake of temperate tree species. TREE PHYSIOLOGY 2018; 38:83-95. [PMID: 29126247 DOI: 10.1093/treephys/tpx131] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Even though the two dominant mycorrhizal associations of temperate tree species differentially couple carbon (C) and nitrogen (N) cycles in temperate forests, systematic differences between the biogeochemical cycles of arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree species remain poorly described. A classification according to the mycorrhizal type offers the chance, though, to develop a global frame concept for the prediction of temperate ecosystem responses to environmental change. Focusing on the influence of mycorrhizal types on two key plant processes of biogeochemical cycling (root exudation and N acquisition), we investigated four temperate deciduous tree species per mycorrhizal type in a drought experiment in large mesocosms. We hypothesized that (H1) C loss by root exudation is higher in ECM than in AM trees, (H2) drought leads to higher reductions in root exudation of drought-sensitive ECM trees and (H3) inorganic N uptake is higher in AM than in ECM trees. In contradiction to H2, we found no systematic difference in root exudation between the mycorrhizal types at ample soil moisture, but almost twofold higher exudation in ECM trees when exposed to soil drought. In addition, photosynthetic C cost of root exudation strongly increased by ~10-fold in drought-treated ECM trees, while it only doubled in AM trees, which confirms H1. With respect to H3, we corroborated that AM trees had higher absolute and relative inorganic N acquisition rates than ECM trees, while the organic N uptake did not differ between mycorrhizal types. We conclude that ECM trees are less efficient in inorganic N uptake than AM trees, but ECM trees increase root C release as an adaptive response to dry soil to maintain hydraulic conductivity and/or nutrient availability. These systematic differences in key biogeochemical processes support hints on the key role of the mycorrhizal types in coupling C and N cycles in temperate forests.
Collapse
Affiliation(s)
- Rebecca Liese
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Torben Lübbe
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Nora W Albers
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Ina C Meier
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| |
Collapse
|
22
|
Sun L, Ataka M, Kominami Y, Yoshimura K. Relationship between fine-root exudation and respiration of two Quercus species in a Japanese temperate forest. TREE PHYSIOLOGY 2017; 37:1011-1020. [PMID: 28338964 DOI: 10.1093/treephys/tpx026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 03/01/2017] [Indexed: 05/07/2023]
Abstract
Plants allocate a considerable amount of carbon (C) to fine roots as respiration and exudation. Fine-root exudation could stimulate microbial activity, which further contributes to soil heterotrophic respiration. Although both root respiration and exudation are important components of belowground C cycling, how they relate to each other is less well known. In this study, we aimed to explore this relationship on mature trees growing in the field. The measurements were performed on two canopy species, Quercus serrata Thunb. and Quercus glauca, in a warm temperate forest. The respiration and exudation rates of the same fine-root segment were measured in parallel with a syringe-basis incubation and a closed static chamber, respectively. We also measured root traits and ectomycorrhizal colonization ratio because these indexes commonly relate to root respiration and reflect root physiology. The microbial activity enhanced by root exudation was investigated by comparing the dissolved organic carbon (DOC) and microbial biomass carbon (MBC) between rhizosphere soils and bulk soils. Mean DOC concentration and MBC were ca two times higher in the rhizosphere soils and positively related to exudation rates, indicating that exudation further relates to the C dynamics in the soils. Flux rates of exudation and respiration were positively correlated with each other. Both root exudation and respiration rates positively related to ectomycorrhizal colonization and root tissue nitrogen, and therefore the relationship between the two fluxes may be attributed to fine-root activity. The flux rates of root respiration were 8.7 and 10.5 times as much as those of exudation on a root-length basis and a root-weight basis, respectively. In spite of the fact that flux rates of respiration and exudation varied enormously among the fine-root segments of the two Quercus species, exudation was in proportion to respiration. This result gives new insight into the fine-root C-allocation strategy and the belowground C dynamics.
Collapse
Affiliation(s)
- Lijuan Sun
- Lab of Forest Ecology, Graduate School of Agriculture, Kyoto University, Kitashirakawa OiwakeCho, Kyoto 606-8502, Japan
- Graduate School of Agriculture, Kyoto University, Main Building of Agriculture School, Kitashirakawa OiwakeCho, Kyoto 606-8502, Japan
| | - Mioko Ataka
- Kansai Research Center, Forestry and Forest Product Research Institute, Japan
| | - Yuji Kominami
- Kansai Research Center, Forestry and Forest Product Research Institute, Japan
| | - Kenichi Yoshimura
- Lab of Forest Hydrology, Graduate School of Agriculture, Kyoto University, Kitashirakawa OiwakeCho, Kyoto 606-8502, Japan
| |
Collapse
|
23
|
Eisenhauer N, Lanoue A, Strecker T, Scheu S, Steinauer K, Thakur MP, Mommer L. Root biomass and exudates link plant diversity with soil bacterial and fungal biomass. Sci Rep 2017; 7:44641. [PMID: 28374800 PMCID: PMC5379681 DOI: 10.1038/srep44641] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/13/2017] [Indexed: 11/30/2022] Open
Abstract
Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity increases substrate availability for soil biota, several studies have speculated that the quantity and diversity of root inputs into the soil, i.e. though root exudates, drive plant diversity effects on soil biota. Here we used a microcosm experiment to study the role of plant species richness on the biomass of soil bacteria and fungi as well as fungal-to-bacterial ratio via root biomass and root exudates. Plant diversity significantly increased shoot biomass, root biomass, the amount of root exudates, bacterial biomass, and fungal biomass. Fungal biomass increased most with increasing plant diversity resulting in a significant shift in the fungal-to-bacterial biomass ratio at high plant diversity. Fungal biomass increased significantly with plant diversity-induced increases in root biomass and the amount of root exudates. These results suggest that plant diversity enhances soil microbial biomass, particularly soil fungi, by increasing root-derived organic inputs.
Collapse
Affiliation(s)
- Nico Eisenhauer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Johannisallee 21, 04103 Leipzig, Germany
| | - Arnaud Lanoue
- Université François Rabelais de Tours. EA 2106 Plant Biotechnology and Biomolecules, 31 Avenue Monge, F-37200 Tours, France
| | - Tanja Strecker
- Georg August University Göttingen, J.F. Blumenbach Institute of Zoology and Anthropology, Berliner Str. 28, 37073 Göttingen, Germany
| | - Stefan Scheu
- Georg August University Göttingen, J.F. Blumenbach Institute of Zoology and Anthropology, Berliner Str. 28, 37073 Göttingen, Germany
| | - Katja Steinauer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Johannisallee 21, 04103 Leipzig, Germany
| | - Madhav P Thakur
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Johannisallee 21, 04103 Leipzig, Germany
| | - Liesje Mommer
- Plant Ecology and Nature Conservation group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| |
Collapse
|
24
|
Karst J, Gaster J, Wiley E, Landhäusser SM. Stress differentially causes roots of tree seedlings to exude carbon. TREE PHYSIOLOGY 2017; 37:154-164. [PMID: 27744381 DOI: 10.1093/treephys/tpw090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/04/2016] [Indexed: 05/29/2023]
Abstract
How carbon (C) flows through plants into soils is poorly understood. Carbon exuded comes from a pool of non-structural carbohydrates (NSC) in roots. Simple models of diffusion across concentration gradients indicate that the more C in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by plants. Thus, stress type may influence exudation independent of NSC. We tested this hypothesis by examining the relationship between NSC in fine roots and exudation of organic C in aspen (Populus tremuloides Michx.) seedlings after exposure to shade, cold soils and drought in a controlled environment. Fine root concentrations of NSC varied by treatment. Mass-specific C exudation increased with increasing fine root sugar concentration in all treatments, but stress type affected exudation independently of sugar concentration. Seedlings exposed to cold soils exuded the most C on a per mass basis. Through 13C labeling, we also found that stressed seedlings allocated relatively more new C to exudates than roots compared with unstressed seedlings. Stress affects exudation of C via mechanisms other than changes in root carbohydrate availability.
Collapse
Affiliation(s)
- Justine Karst
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Jacob Gaster
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| |
Collapse
|
25
|
Savage JA, Clearwater MJ, Haines DF, Klein T, Mencuccini M, Sevanto S, Turgeon R, Zhang C. Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology? PLANT, CELL & ENVIRONMENT 2016; 39:709-25. [PMID: 26147312 DOI: 10.1111/pce.12602] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/30/2015] [Accepted: 06/19/2015] [Indexed: 05/02/2023]
Abstract
Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment.
Collapse
Affiliation(s)
- Jessica A Savage
- Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA, 02131, USA
| | | | - Dustin F Haines
- Department of Environmental Conservation, University of Massachusetts, 160 Holdsworth Way, Amherst, MA, 01003, USA
| | - Tamir Klein
- Institute of Botany, University of Basel, Schoenbeinstrasse 6, 4056, Basel, Switzerland
| | - Maurizio Mencuccini
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, EH9 3JN, Edinburgh, UK
- ICREA at CREAF, Campus de UAB, Cerdanyola del Valles, Barcelona, 08023, Spain
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Robert Turgeon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Cankui Zhang
- Department of Agronomy, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
26
|
Mommer L, Kirkegaard J, van Ruijven J. Root-Root Interactions: Towards A Rhizosphere Framework. TRENDS IN PLANT SCIENCE 2016; 21:209-217. [PMID: 26832947 DOI: 10.1016/j.tplants.2016.01.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 05/20/2023]
Abstract
Plant scientists have made great progress in understanding molecular mechanisms controlling root responses to nutrients of arabidopsis (Arabidopsis thaliana) plants under controlled conditions. Simultaneously, ecologists and agronomists have demonstrated that root-root interactions involve more than competition for nutrients. Here, we highlight the importance of both root exudates and soil microbes for root-root interactions, ubiquitous in natural and agricultural ecosystems. We argue that it is time to bring together the recent insights from both scientific disciplines to fully understand root functioning in the real world.
Collapse
Affiliation(s)
- Liesje Mommer
- Plant Ecology and Nature Conservation Group, Wageningen University, PO Box 47, 6700AA Wageningen, The Netherlands.
| | - John Kirkegaard
- CSIRO-Agriculture, PO Box 1600, Canberra, ACT 2601, Australia
| | - Jasper van Ruijven
- Plant Ecology and Nature Conservation Group, Wageningen University, PO Box 47, 6700AA Wageningen, The Netherlands
| |
Collapse
|
27
|
Churchland C, Grayston SJ. Specificity of plant-microbe interactions in the tree mycorrhizosphere biome and consequences for soil C cycling. Front Microbiol 2014; 5:261. [PMID: 24917855 PMCID: PMC4042908 DOI: 10.3389/fmicb.2014.00261] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 05/13/2014] [Indexed: 01/22/2023] Open
Abstract
Mycorrhizal associations are ubiquitous and form a substantial component of the microbial biomass in forest ecosystems and fluxes of C to these belowground organisms account for a substantial portion of carbon assimilated by forest vegetation. Climate change has been predicted to alter belowground plant-allocated C which may cause compositional shifts in soil microbial communities, and it has been hypothesized that this community change will influence C mitigation in forest ecosystems. Some 10,000 species of ectomycorrhizal fungi are currently recognized, some of which are host specific and will only associate with a single tree species, for example, Suillus grevillei with larch. Mycorrhizae are a strong sink for plant C, differences in mycorrhizal anatomy, particularly the presence and extent of emanating hyphae, can affect the amount of plant C allocated to these assemblages. Mycorrhizal morphology affects not only spatial distribution of C in forests, but also differences in the longevity of these diverse structures may have important consequences for C sequestration in soil. Mycorrhizal growth form has been used to group fungi into distinctive functional groups that vary qualitatively and spatially in their foraging and nutrient acquiring potential. Through new genomic techniques we are beginning to understand the mechanisms involved in the specificity and selection of ectomycorrhizal associations though much less is known about arbuscular mycorrhizal associations. In this review we examine evidence for tree species- mycorrhizal specificity, and the mechanisms involved (e.g., signal compounds). We also explore what is known about the effects of these associations and interactions with other soil organisms on the quality and quantity of C flow into the mycorrhizosphere (the area under the influence of mycorrhizal root tips), including spatial and seasonal variations. The enormity of the mycorrhizosphere biome in forests and its potential to sequester substantial C belowground highlights the vital importance of increasing our knowledge of the dynamics of the different mycorrhizal functional groups in diverse forests.
Collapse
Affiliation(s)
| | - Sue J. Grayston
- Belowground Ecosystem Group, Department of Forest and Conservation Sciences, University of British ColumbiaVancouver, BC, Canada
| |
Collapse
|
28
|
Chaparro JM, Badri DV, Vivanco JM. Rhizosphere microbiome assemblage is affected by plant development. THE ISME JOURNAL 2014; 8:790-803. [PMID: 24196324 PMCID: PMC3960538 DOI: 10.1038/ismej.2013.196] [Citation(s) in RCA: 604] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 08/22/2013] [Accepted: 09/29/2013] [Indexed: 01/11/2023]
Abstract
There is a concerted understanding of the ability of root exudates to influence the structure of rhizosphere microbial communities. However, our knowledge of the connection between plant development, root exudation and microbiome assemblage is limited. Here, we analyzed the structure of the rhizospheric bacterial community associated with Arabidopsis at four time points corresponding to distinct stages of plant development: seedling, vegetative, bolting and flowering. Overall, there were no significant differences in bacterial community structure, but we observed that the microbial community at the seedling stage was distinct from the other developmental time points. At a closer level, phylum such as Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria and specific genera within those phyla followed distinct patterns associated with plant development and root exudation. These results suggested that the plant can select a subset of microbes at different stages of development, presumably for specific functions. Accordingly, metatranscriptomics analysis of the rhizosphere microbiome revealed that 81 unique transcripts were significantly (P<0.05) expressed at different stages of plant development. For instance, genes involved in streptomycin synthesis were significantly induced at bolting and flowering stages, presumably for disease suppression. We surmise that plants secrete blends of compounds and specific phytochemicals in the root exudates that are differentially produced at distinct stages of development to help orchestrate rhizosphere microbiome assemblage.
Collapse
Affiliation(s)
- Jacqueline M Chaparro
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
| | - Dayakar V Badri
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
| | - Jorge M Vivanco
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
| |
Collapse
|
29
|
Alexou M. Development-specific responses to drought stress in Aleppo pine (Pinus halepensis Mill.) seedlings. TREE PHYSIOLOGY 2013; 33:1030-1042. [PMID: 24200584 DOI: 10.1093/treephys/tpt084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Aleppo pine (Pinus halepensis Mill.) is a pioneer species, highly competitive due to exceptional resistance to drought. To investigate the stress resistance in the first and second year of development, a steady-state drought experiment was implemented. Photosynthesis (A(net)), stomatal conductance and transpiration (E) were measured on three different sampling dates together with phloem soluble sugars, amino acids and non-structural proteins. Needle ascorbic acid (AsA) and reactive oxygen species were measured to evaluate the seedlings' drought stress condition in the final sampling. Drought impaired A(net) and E by 35 and 31%, respectively, and increased AsA levels up to 10-fold, without significant impact on the phloem metabolites. Phloem sugars related to temperature fluctuations rather than soil moisture and did not relate closely to A(net) levels. Sugars and proteins decreased between the second and third sampling date by 56 and 61%, respectively, and the ratio of sugars to amino acids decreased between the first and third sampling by 81%, while A(net) and water-use efficiency (A(net)/E) decreased only in the older seedlings. Although gas exchange was higher in the older seedlings, ascorbic acid and phloem metabolites were higher in the younger seedlings. It was concluded that the drought stress responses depended significantly on developmental stage, and research on the physiology of Aleppo pine regeneration should focus more on temperature conditions and the duration of drought than its severity.
Collapse
Affiliation(s)
- Maria Alexou
- Forest Research Institute, National Agricultural Research Foundation, Vassilika 57005, Thessaloniki, Greece
| |
Collapse
|