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Hornstein ED, Charles M, Franklin M, Edwards B, Vintila S, Kleiner M, Sederoff H. IPD3, a master regulator of arbuscular mycorrhizal symbiosis, affects genes for immunity and metabolism of non-host Arabidopsis when restored long after its evolutionary loss. PLANT MOLECULAR BIOLOGY 2024; 114:21. [PMID: 38368585 PMCID: PMC10874911 DOI: 10.1007/s11103-024-01422-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/20/2024] [Indexed: 02/19/2024]
Abstract
Arbuscular mycorrhizal symbiosis (AM) is a beneficial trait originating with the first land plants, which has subsequently been lost by species scattered throughout the radiation of plant diversity to the present day, including the model Arabidopsis thaliana. To explore if elements of this apparently beneficial trait are still present and could be reactivated we generated Arabidopsis plants expressing a constitutively active form of Interacting Protein of DMI3, a key transcription factor that enables AM within the Common Symbiosis Pathway, which was lost from Arabidopsis along with the AM host trait. We characterize the transcriptomic effect of expressing IPD3 in Arabidopsis with and without exposure to the AM fungus (AMF) Rhizophagus irregularis, and compare these results to the AM model Lotus japonicus and its ipd3 knockout mutant cyclops-4. Despite its long history as a non-AM species, restoring IPD3 in the form of its constitutively active DNA-binding domain to Arabidopsis altered expression of specific gene networks. Surprisingly, the effect of expressing IPD3 in Arabidopsis and knocking it out in Lotus was strongest in plants not exposed to AMF, which is revealed to be due to changes in IPD3 genotype causing a transcriptional state, which partially mimics AMF exposure in non-inoculated plants. Our results indicate that molecular connections to symbiosis machinery remain in place in this nonAM species, with implications for both basic science and the prospect of engineering this trait for agriculture.
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Affiliation(s)
- Eli D Hornstein
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Melodi Charles
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Megan Franklin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Brianne Edwards
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Simina Vintila
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Heike Sederoff
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA.
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2
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Allen MF, Shulman H, Rundel PW, Harmon TC, Aronson EL. Leaf-cutter ants - mycorrhizal fungi: observations and research questions from an unexpected mutualism. FRONTIERS IN FUNGAL BIOLOGY 2023; 4:1241916. [PMID: 38033376 PMCID: PMC10687443 DOI: 10.3389/ffunb.2023.1241916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 10/13/2023] [Indexed: 12/02/2023]
Abstract
Leaf-cutter ants (LCAs) are widely distributed and alter the physical and biotic architecture above and below ground. In neotropical rainforests, they create aboveground and belowground disturbance gaps that facilitate oxygen and carbon dioxide exchange. Within the hyperdiverse neotropical rainforests, arbuscular mycorrhizal (AM) fungi occupy nearly all of the forest floor. Nearly every cubic centimeter of soil contains a network of hyphae of Glomeromycotina, fungi that form arbuscular mycorrhizae. Our broad question is as follows: how can alternative mycorrhizae, which are-especially ectomycorrhizae-essential for the survival of some plant species, become established? Specifically, is there an ant-mycorrhizal fungus interaction that facilitates their establishment in these hyperdiverse ecosystems? In one lowland Costa Rican rainforest, nests of the LCA Atta cephalotes cover approximately 1.2% of the land surface that is broadly scattered throughout the forest. On sequencing the DNA from soil organisms, we found the inocula of many AM fungi in their nests, but the nests also contained the inocula of ectomycorrhizal, orchid mycorrhizal, and ericoid mycorrhizal fungi, including Scleroderma sinnamariense, a fungus critical to Gnetum leyboldii, an obligate ectomycorrhizal plant. When the nests were abandoned, new root growth into the nest offered opportunities for new mycorrhizal associations to develop. Thus, the patches created by LCAs appear to be crucial sites for the establishment and survival of shifting mycorrhizal plant-fungal associations, in turn facilitating the high diversity of these communities. A better understanding of the interactions of organisms, including cross-kingdom and ant-mycorrhizal fungal interactions, would improve our understanding of how these ecosystems might tolerate environmental change.
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Affiliation(s)
- Michael F. Allen
- Center for Conservation Biology, Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
| | - Hannah Shulman
- Center for Conservation Biology, Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
| | - Philip W. Rundel
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Thomas C. Harmon
- School of Engineering and Environmental Systems Program, University of California, Merced, Merced, CA, United States
| | - Emma L. Aronson
- Center for Conservation Biology, Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
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3
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Hornstein ED, Charles M, Franklin M, Edwards B, Vintila S, Kleiner M, Sederoff H. Re-engineering a lost trait: IPD3, a master regulator of arbuscular mycorrhizal symbiosis, affects genes for immunity and metabolism of non-host Arabidopsis when restored long after its evolutionary loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531368. [PMID: 36945518 PMCID: PMC10028889 DOI: 10.1101/2023.03.06.531368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Arbuscular mycorrhizal symbiosis (AM) is a beneficial trait originating with the first land plants, which has subsequently been lost by species scattered throughout the radiation of plant diversity to the present day, including the model Arabidopsis thaliana. To explore why an apparently beneficial trait would be repeatedly lost, we generated Arabidopsis plants expressing a constitutively active form of Interacting Protein of DMI3, a key transcription factor that enables AM within the Common Symbiosis Pathway, which was lost from Arabidopsis along with the AM host trait. We characterize the transcriptomic effect of expressing IPD3 in Arabidopsis with and without exposure to the AM fungus (AMF) Rhizophagus irregularis, and compare these results to the AM model Lotus japonicus and its ipd3 knockout mutant cyclops-4. Despite its long history as a non-AM species, restoring IPD3 in the form of its constitutively active DNA-binding domain to Arabidopsis altered expression of specific gene networks. Surprisingly, the effect of expressing IPD3 in Arabidopsis and knocking it out in Lotus was strongest in plants not exposed to AMF, which is revealed to be due to changes in IPD3 genotype causing a transcriptional state which partially mimics AMF exposure in non-inoculated plants. Our results indicate that despite the long interval since loss of AM and IPD3 in Arabidopsis, molecular connections to symbiosis machinery remain in place in this nonAM species, with implications for both basic science and the prospect of engineering this trait for agriculture.
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Affiliation(s)
- Eli D Hornstein
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Melodi Charles
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Megan Franklin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Brianne Edwards
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Simina Vintila
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Heike Sederoff
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
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4
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Newman A, Picot E, Davies S, Hilton S, Carré IA, Bending GD. Circadian rhythms in the plant host influence rhythmicity of rhizosphere microbiota. BMC Biol 2022; 20:235. [PMID: 36266698 PMCID: PMC9585842 DOI: 10.1186/s12915-022-01430-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 09/30/2022] [Indexed: 11/18/2022] Open
Abstract
Background Recent studies demonstrated that microbiota inhabiting the plant rhizosphere exhibit diel changes in abundance. To investigate the impact of plant circadian rhythms on bacterial and fungal rhythms in the rhizosphere, we analysed temporal changes in fungal and bacterial communities in the rhizosphere of Arabidopsis plants overexpressing or lacking function of the circadian clock gene LATE ELONGATED HYPOCOTYL (LHY). Results Under diel light–dark cycles, the knock-out mutant lhy-11 and the gain-of-function mutant lhy-ox both exhibited gene expression rhythms with altered timing and amplitude compared to wild-type plants. Distinct sets of bacteria and fungi were found to display rhythmic changes in abundance in the rhizosphere of both of these mutants, suggesting that abnormal patterns of rhythmicity in the plant host caused temporal reprogramming of the rhizosphere microbiome. This was associated with changes in microbial community structure, including changes in the abundance of fungal guilds known to impact on plant health. Under constant environmental conditions, microbial rhythmicity persisted in the rhizosphere of wild-type plants, indicating control by a circadian oscillator. In contrast, loss of rhythmicity in lhy-ox plants was associated with disrupted rhythms for the majority of rhizosphere microbiota. Conclusions These results show that aberrant function of the plant circadian clock is associated with altered rhythmicity of rhizosphere bacteria and fungi. In the long term, this leads to changes in composition of the rhizosphere microbiome, with potential consequences for plant health. Further research will be required to understand the functional implications of these changes and how they impact on plant health and productivity. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01430-z.
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Affiliation(s)
- Amy Newman
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK.,Present address: National STEM Learning Centre, University of York, York, YO10 5DD, UK
| | - Emma Picot
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK
| | - Sian Davies
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK.,Present address: Micropathology Ltd, Venture Centre, Sir William Lyons Road, Coventry, CV4 7EZ, UK
| | - Sally Hilton
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK.,Present address: Micropathology Ltd, Venture Centre, Sir William Lyons Road, Coventry, CV4 7EZ, UK
| | - Isabelle A Carré
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK.
| | - Gary D Bending
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, West Midlands, UK
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Fernandez-Bou AS, Dierick D, Allen MF, Harmon TC. Precipitation-drainage cycles lead to hot moments in soil carbon dioxide dynamics in a Neotropical wet forest. GLOBAL CHANGE BIOLOGY 2020; 26:5303-5319. [PMID: 32458420 DOI: 10.1111/gcb.15194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Soil CO2 concentrations and emissions from tropical forests are modulated seasonally by precipitation. However, subseasonal responses to meteorological events (e.g., storms, drought) are less well known. Here, we present the effects of meteorological variability on short-term (hours to months) dynamics of soil CO2 concentrations and emissions in a Neotropical wet forest. We continuously monitored soil temperature, moisture, and CO2 for a three-year period (2015-2017), encompassing normal conditions, floods, a dry El Niño period, and a hurricane. We used a coupled model (Hydrus-1D) for soil water propagation, heat transfer, and diffusive gas transport to explain observed soil moisture, soil temperature, and soil CO2 concentration responses to meteorology, and we estimated soil CO2 efflux with a gradient-flux model. Then, we predicted changes in soil CO2 concentrations and emissions under different warming climate change scenarios. Observed short-term (hourly to daily) soil CO2 concentration responded more to precipitation than to other meteorological variables (including lower pressure during the hurricane). Observed soil CO2 failed to exhibit diel patterns (associated with diel temperature fluctuations in drier climates), except during the drier El Niño period. Climate change scenarios showed enhanced soil CO2 due to warmer conditions, while precipitation played a critical role in moderating the balance between concentrations and emissions. The scenario with increased precipitation (based on a regional model projection) led to increases of +11% in soil CO2 concentrations and +4% in soil CO2 emissions. The scenario with decreased precipitation (based on global circulation model projections) resulted in increases of +4% in soil CO2 concentrations and +18% in soil CO2 emissions, and presented more prominent hot moments in soil CO2 outgassing. These findings suggest that soil CO2 will increase under warmer climate in tropical wet forests, and precipitation patterns will define the intensity of CO2 outgassing hot moments.
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Affiliation(s)
- Angel Santiago Fernandez-Bou
- Environmental Systems Graduate Program , Department of Civil & Environmental Engineering, University of California Merced, Merced, CA, USA
| | - Diego Dierick
- La Selva Biological Station, Organization for Tropical Studies, Costa Rica
- Department of Biological Sciences, Florida International University, Miami, FL, USA
| | - Michael F Allen
- Department of Microbiology & Plant Pathology and Center for Conservation Biology, University of California Riverside, Riverside, CA, USA
| | - Thomas C Harmon
- Environmental Systems Graduate Program , Department of Civil & Environmental Engineering, University of California Merced, Merced, CA, USA
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Lee SJ, Morse D, Hijri M. Holobiont chronobiology: mycorrhiza may be a key to linking aboveground and underground rhythms. MYCORRHIZA 2019; 29:403-412. [PMID: 31190278 DOI: 10.1007/s00572-019-00903-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
Circadian clocks are nearly ubiquitous timing mechanisms that can orchestrate rhythmic behavior and gene expression in a wide range of organisms. Clock mechanisms are becoming well understood in fungal, animal, and plant model systems, yet many of these organisms are surrounded by a complex and diverse microbiota which should be taken into account when examining their biology. Of particular interest are the symbiotic relationships between organisms that have coevolved over time, forming a unit called a holobiont. Several studies have now shown linkages between the circadian rhythms of symbiotic partners. Interrelated regulation of holobiont circadian rhythms seems thus important to coordinate shifts in activity over the day for all the partners. Therefore, we suggest that the classical view of "chronobiological individuals" should include "a holobiont" rather than an organism. Unfortunately, mechanisms that may regulate interspecies temporal acclimation and the evolution of the circadian clock in holobionts are far from being understood. For the plant holobiont, our understanding is particularly limited. In this case, the holobiont encompasses two different ecosystems, one above and the other below the ground, with the two potentially receiving timing information from different synchronizing signals (Zeitgebers). The arbuscular mycorrhizal (AM) symbiosis, formed by plant roots and fungi, is one of the oldest and most widespread associations between organisms. By mediating the nutritional flux between the plant and the many microbes in the soil, AM symbiosis constitutes the backbone of the plant holobiont. Even though the importance of the AM symbiosis has been well recognized in agricultural and environmental sciences, its circadian chronobiology remains almost completely unknown. We have begun to study the circadian clock of arbuscular mycorrhizal fungi, and we compile and here discuss the available information on the subject. We propose that analyzing the interrelated temporal organization of the AM symbiosis and determining its underlying mechanisms will advance our understanding of the role and coordination of circadian clocks in holobionts in general.
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Affiliation(s)
- Soon-Jae Lee
- Institut de Recherche en Biologie Végétale (IRBV), Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
- Department of Ecology and Evolution, University of Lausanne, 1015, Lausanne, Switzerland
| | - David Morse
- Institut de Recherche en Biologie Végétale (IRBV), Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
| | - Mohamed Hijri
- Institut de Recherche en Biologie Végétale (IRBV), Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
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Inyang EI, Hix RL, Tsolova V, Rohde BB, Dosunmu O, Mankin RW. Subterranean Acoustic Activity Patterns of Vitacea polistiformis (Lepidoptera: Sesiidae) in Relation to Abiotic and Biotic Factors. INSECTS 2019; 10:insects10090267. [PMID: 31443578 PMCID: PMC6780318 DOI: 10.3390/insects10090267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/17/2019] [Accepted: 08/20/2019] [Indexed: 11/16/2022]
Abstract
Grape root borer (GRB), Vitacea polistiformis, is a root-feeding pest of grapevines in the US southeast that causes underground damage well before vines show visible symptoms. A 269-d study was conducted at 31 sites in a Florida vineyard to record short bursts of insect movement and feeding vibrations in grapevine root systems and provide information that can improve timing and targeting of GRB management efforts. Characteristic spectral and temporal patterns in the subterranean vibrations facilitated discrimination of GRB from background noise and non-targeted arthropods. Infestation likelihood of GRB at each site was estimated from previous studies relating infestation to burst rate. In all, 39% of recordings indicated low infestation likelihood. Sites with medium or high infestation likelihood were confined to a small region of the vineyard where a vine with larval feeding damage was confirmed. The restricted area suggests that the biological control or chemical treatments could be reduced elsewhere. Acoustic activity was significantly greater in fall and winter than in spring, and greater in evening than afternoon; fall evenings seemed best for GRB acoustic surveys. The GRB seasonal and circadian acoustic variation reflected phenological variation in grape root growth and nutrients and was not significantly correlated with temperature.
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Affiliation(s)
- Edidiong I Inyang
- Center for Biological Control, Florida A&M University (FAMU), Tallahassee, FL 32307, USA
| | - Raymond L Hix
- Center for Biological Control, Florida A&M University (FAMU), Tallahassee, FL 32307, USA
| | | | - Barukh B Rohde
- Electrical and Computer Engineering Department, University of Florida, Gainesville, FL 32611, USA
| | - Omotola Dosunmu
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611, USA
| | - Richard W Mankin
- US Department of Agriculture, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA.
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8
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Leyva-Morales R, Gavito ME, Carrillo-Saucedo SM. Morphological and physiological responses of the external mycelium of Rhizophagus intraradices to water stress. MYCORRHIZA 2019; 29:141-147. [PMID: 30643987 DOI: 10.1007/s00572-019-00880-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
Most studies dealing with mycorrhizal associations and drought have focused on the plants, not on the fungi, and tolerance and adaptations of arbuscular mycorrhizal (AM) fungi to cope with water stress are virtually unknown. This study was conducted to assess how water stress directly affects an AM fungus isolate, particularly through morphological and physiological changes in the external mycelium. We used two-compartment pots separated by mesh and an air gap that allowed us to apply water stress treatments only to the external mycelium. Clover (Trifolium subterraneum L.) plants inoculated with Rhizophagus intraradices grew at high humidity until external mycorrhizal mycelium developed in the mycelium compartment. Then, we started three watering treatments: high (H, 70% of soil water holding capacity), low (L, 10%), and mixed watering (HLHL, 70-10-70-10%) only in the hyphal compartment. The HLHL treatment was rewetted once to 70% after 42 days. We measured total mycelium length, hyphal length in diameter categories, respiration activity, and protoplasm fragmentation 42 and 76 days after starting the treatments. Rhizophagus intraradices mycelium responded to water stress by reducing its length, maintaining larger diameter hyphae, and concentrating protoplasm activity in fragments in the HLHL and L treatments. In both water stress treatments, changes suggested a trade-off between avoiding desiccation and storing resources, and maintaining soil exploration and water uptake capacity.
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Affiliation(s)
- Ricardo Leyva-Morales
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México-Campus Morelia, Apartado Postal 27-3 Santa María de Guido, 58090, Morelia, Michoacán, Mexico
| | - Mayra E Gavito
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México-Campus Morelia, Apartado Postal 27-3 Santa María de Guido, 58090, Morelia, Michoacán, Mexico.
| | - S Margarita Carrillo-Saucedo
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México-Campus Morelia, Apartado Postal 27-3 Santa María de Guido, 58090, Morelia, Michoacán, Mexico
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Powell JR, Rillig MC. Biodiversity of arbuscular mycorrhizal fungi and ecosystem function. THE NEW PHYTOLOGIST 2018; 220:1059-1075. [PMID: 29603232 DOI: 10.1111/nph.15119] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/19/2018] [Indexed: 05/22/2023]
Abstract
Contents Summary 1059 I. Introduction: pathways of influence and pervasiveness of effects 1060 II. AM fungal richness effects on ecosystem functions 1062 III. Other dimensions of biodiversity 1062 IV. Back to basics - primary axes of niche differentiation by AM fungi 1066 V. Functional diversity of AM fungi - a role for biological stoichiometry? 1067 VI. Past, novel and future ecosystems 1068 VII. Opportunities and the way forward 1071 Acknowledgements 1072 References 1072 SUMMARY: Arbuscular mycorrhizal (AM) fungi play important functional roles in ecosystems, including the uptake and transfer of nutrients, modification of the physical soil environment and alteration of plant interactions with other biota. Several studies have demonstrated the potential for variation in AM fungal diversity to also affect ecosystem functioning, mainly via effects on primary productivity. Diversity in these studies is usually characterized in terms of the number of species, unique evolutionary lineages or complementary mycorrhizal traits, as well as the ability of plants to discriminate among AM fungi in space and time. However, the emergent outcomes of these relationships are usually indirect, and thus context dependent, and difficult to predict with certainty. Here, we advocate a fungal-centric view of AM fungal biodiversity-ecosystem function relationships that focuses on the direct and specific links between AM fungal fitness and consequences for their roles in ecosystems, especially highlighting functional diversity in hyphal resource economics. We conclude by arguing that an understanding of AM fungal functional diversity is fundamental to determine whether AM fungi have a role in the exploitation of marginal/novel environments (whether past, present or future) and highlight avenues for future research.
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Affiliation(s)
- Jeff R Powell
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Matthias C Rillig
- Freie Universität Berlin, Institut für Biologie, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
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10
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Taniguchi T, Kitajima K, Douhan GW, Yamanaka N, Allen MF. A pulse of summer precipitation after the dry season triggers changes in ectomycorrhizal formation, diversity, and community composition in a Mediterranean forest in California, USA. MYCORRHIZA 2018; 28:665-677. [PMID: 30105498 PMCID: PMC6182365 DOI: 10.1007/s00572-018-0859-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
Rapid responses of microbial biomass and community composition following a precipitation event have been reported for soil bacteria and fungi, but measurements characterizing ectomycorrhizal fungi remain limited. The response of ectomycorrhizal fungi after a precipitation event is crucial to understanding biogeochemical cycles and plant nutrition. Here, we examined changes in ectomycorrhizal formation, diversity, and community composition at the end of a summer drought and following precipitation events in a conifer-oak mixed forest under a semiarid, Mediterranean-type climate in CA, USA. To study the effects of different amounts of precipitation, a water addition treatment was also undertaken. Ectomycorrhizal fungal diversity and community composition changed within 6 days following precipitation, with increased simultaneous mortality and re-growth. Ectomycorrhizal diversity increased and community composition changed both in the natural rainfall (less than 10 mm) and water addition (50 mm) treatments, but larger decreases in ectomycorrhizal diversity were observed from 9 to 16 days after precipitation in the water addition treatment. The changes were primarily a shift in richness and abundance of Basidiomycota species, indicating higher drought sensitivity of Basidiomycota species compared with Ascomycota species. Our results indicate that ectomycorrhizal formation, diversity, and community composition rapidly respond to both precipitation events and to the amount of precipitation. These changes affect ecosystem functions, such as nutrient cycling, decomposition, and plant nutrient uptake, in semiarid regions.
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Affiliation(s)
- Takeshi Taniguchi
- Center for Conservation Biology, University of California, Riverside, CA, 92521, USA.
- Arid Land Research Center, Tottori University, Tottori, 680-0001, Japan.
| | - Kuni Kitajima
- Center for Conservation Biology, University of California, Riverside, CA, 92521, USA
| | - Greg W Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- University of California Cooperative Extension, 4437-B S. Laspina St., Tulare, CA, 93274, USA
| | - Norikazu Yamanaka
- Arid Land Research Center, Tottori University, Tottori, 680-0001, Japan
| | - Michael F Allen
- Center for Conservation Biology, University of California, Riverside, CA, 92521, USA
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- Department of Biology, University of California, Riverside, CA, 92521, USA
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11
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Lee SJ, Kong M, Morse D, Hijri M. Expression of putative circadian clock components in the arbuscular mycorrhizal fungus Rhizoglomus irregulare. MYCORRHIZA 2018; 28:523-534. [PMID: 29931403 DOI: 10.1007/s00572-018-0843-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are obligatory plant symbionts that live underground, so few studies have examined their response to light. Responses to blue light by other fungi can be mediated by White Collar-1 (WC-1) and WC-2 proteins. These wc genes, together with the frequency gene (frq), also form part of the endogenous circadian clock. The clock mechanism has never been studied in AMF, although circadian growth of their hyphae in the field has been reported. Using both genomic and transcriptomic data, we have found homologs of wc-1, wc-2, and frq and related circadian clock genes in the arbuscular mycorrhizal fungus Rhizoglomus irregulare (synonym Rhizophagus irregularis). Gene expression of wc-1, wc-2, and frq was analyzed using RT-qPCR on RNA extracted from germinating spores and from fungal material cultivated in vitro with transformed carrot roots. We found that all three core clock genes were expressed in both pre- and post-mycorrhizal stages of R. irregulare growth. Similar to the model fungus Neurospora crassa, the core circadian oscillator gene frq was induced by brief light stimulation. The presence of circadian clock and output genes in R. irregulare opens the door to the study of circadian clocks in the fungal partner of plant-AMF symbiosis. Our finding also provides new insight into the evolution of the circadian frq gene in fungi.
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Affiliation(s)
- Soon-Jae Lee
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
| | - Mengxuan Kong
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
| | - David Morse
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
| | - Mohamed Hijri
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
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Larrondo LF, Canessa P. The Clock Keeps on Ticking: Emerging Roles for Circadian Regulation in the Control of Fungal Physiology and Pathogenesis. Curr Top Microbiol Immunol 2018; 422:121-156. [PMID: 30255278 DOI: 10.1007/82_2018_143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Tic-tac, tic-tac, the sound of time is familiar to us, yet, it also silently shapes daily biological processes conferring 24-hour rhythms in, among others, cellular and systemic signaling, gene expression, and metabolism. Indeed, circadian clocks are molecular machines that permit temporal control of a variety of processes in individuals, with a close to 24-hour period, optimizing cellular dynamics in synchrony with daily environmental cycles. For over three decades, the molecular bases of these clocks have been extensively described in the filamentous fungus Neurospora crassa, yet, there have been few molecular studies in fungi other than Neurospora, despite evidence of rhythmic phenomena in many fungal species, including pathogenic ones. This chapter will revise the mechanisms underlying clock regulation in the model fungus N. crassa, as well as recent findings obtained in several fungi. In particular, this chapter will review the effect of circadian regulation of virulence and organismal interactions, focusing on the phytopathogen Botrytis cinerea, as well as several entomopathogenic fungi, including the behavior-manipulating species Ophiocordyceps kimflemingiae and Entomophthora muscae. Finally, this review will comment current efforts in the study of mammalian pathogenic fungi, while highlighting recent circadian lessons from parasites such as Trypanosoma and Plasmodium. The clock keeps on ticking, whether we can hear it or not.
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Affiliation(s)
- Luis F Larrondo
- Millennium Institute for Integrative Biology (iBio), Santiago, Chile. .,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Paulo Canessa
- Millennium Institute for Integrative Biology (iBio), Santiago, Chile.,Facultad de Ciencias de la Vida, Centro de Biotecnologia Vegetal, Universidad Andres Bello, Santiago, Chile
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Meitern A, Õunapuu-Pikas E, Sellin A. Circadian patterns of xylem sap properties and their covariation with plant hydraulic traits in hybrid aspen. JOURNAL OF PLANT PHYSIOLOGY 2017; 213:148-156. [PMID: 28384532 DOI: 10.1016/j.jplph.2017.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/21/2017] [Accepted: 03/21/2017] [Indexed: 06/07/2023]
Abstract
Physiological processes taking place in plants are subject to diverse circadian patterns but some of them are poorly documented in natural conditions. The daily dynamics of physico-chemical properties of xylem sap and their covariation with tree hydraulic traits were investigated in hybrid aspen (Populus tremula L.×P. tremuloides Michx) in field conditions in order to clarify which environmental drivers govern the daily variation in these parameters. K+ concentration ([K+]), electrical conductivity (σsap), osmolality (Osm) and pH of the xylem sap, as well as branch hydraulic traits, were measured in the field over 24-h cycles. All studied xylem sap properties and hydraulic characteristics including whole-branch (Kwb), leaf blade (Klb) and petiole hydraulic conductances (KP) showed clear daily dynamics. Air temperature (TA) and photosynthetic photon flux density (PPFD), but also water vapour pressure deficit (VPD) and relative humidity (RH), had significant impacts on KwbKlb, KP, [K+] and σsap. Osm varied only with light intensity, while KB varied depending on atmospheric evaporative demand expressed as TA, VPD or RH. Xylem sap pH depended inversely on soil water potential (ΨS) and during daylight also on VPD. Although soil water content was close to saturation during the study period, ΨS influenced also [K+] and σsap. The present study presents evidence of coupling between circadian patterns of xylem sap properties and plant hydraulic conductance providing adequate water supply to foliage under environmental conditions characterised by diurnal variation.
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Affiliation(s)
- Annika Meitern
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia.
| | - Eele Õunapuu-Pikas
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia
| | - Arne Sellin
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia
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14
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Uniting species- and community-oriented approaches to understand arbuscular mycorrhizal fungal diversity. FUNGAL ECOL 2016. [DOI: 10.1016/j.funeco.2016.07.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Iversen CM, Sloan VL, Sullivan PF, Euskirchen ES, McGuire AD, Norby RJ, Walker AP, Warren JM, Wullschleger SD. The unseen iceberg: plant roots in arctic tundra. THE NEW PHYTOLOGIST 2015; 205:34-58. [PMID: 25209220 DOI: 10.1111/nph.13003] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 07/10/2014] [Indexed: 06/03/2023]
Abstract
Plant roots play a critical role in ecosystem function in arctic tundra, but root dynamics in these ecosystems are poorly understood. To address this knowledge gap, we synthesized available literature on tundra roots, including their distribution, dynamics and contribution to ecosystem carbon and nutrient fluxes, and highlighted key aspects of their representation in terrestrial biosphere models. Across all tundra ecosystems, belowground plant biomass exceeded aboveground biomass, with the exception of polar desert tundra. Roots were shallowly distributed in the thin layer of soil that thaws annually, and were often found in surface organic soil horizons. Root traits - including distribution, chemistry, anatomy and resource partitioning - play an important role in controlling plant species competition, and therefore ecosystem carbon and nutrient fluxes, under changing climatic conditions, but have only been quantified for a small fraction of tundra plants. Further, the annual production and mortality of fine roots are key components of ecosystem processes in tundra, but extant data are sparse. Tundra root traits and dynamics should be the focus of future research efforts. Better representation of the dynamics and characteristics of tundra roots will improve the utility of models for the evaluation of the responses of tundra ecosystems to changing environmental conditions.
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Affiliation(s)
- Colleen M Iversen
- Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA; Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA
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Chaudhary VB, O'Dell TE, Rillig MC, Johnson NC. Multiscale patterns of arbuscular mycorrhizal fungal abundance and diversity in semiarid shrublands. FUNGAL ECOL 2014. [DOI: 10.1016/j.funeco.2014.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kobae Y, Gutjahr C, Paszkowski U, Kojima T, Fujiwara T, Hata S. Lipid droplets of arbuscular mycorrhizal fungi emerge in concert with arbuscule collapse. PLANT & CELL PHYSIOLOGY 2014; 55:1945-53. [PMID: 25231957 DOI: 10.1093/pcp/pcu123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Plants share photosynthetically fixed carbon with arbuscular mycorrhizal (AM) fungi to maintain their growth and nutrition. AM fungi are oleogenic fungi that contain numerous lipid droplets in their syncytial mycelia during most of their life cycle. These lipid droplets are probably used for supporting growth of extraradical mycelia and propagation; however, when and where the lipid droplets are produced remains unclear. To address these issues, we investigated the correlation between intracellular colonization stages and the appearance of fungal lipid droplets in roots by a combination of vital staining of fungal structures, selective staining of lipids and live imaging. We discovered that a surge of lipid droplets coincided with the collapse of arbuscular branches, indicating that arbuscule collapse and the emergence of lipid droplets may be associated processes. This phenomenon was observed in the model AM fungus Rhizophagus irregularis and the ancestral member of AM fungi Paraglomus occultum. Because the collapsing arbuscules were metabolically inactive, the emerged lipid droplets are probably derived from preformed lipids but not de novo synthesized. Our observations highlight a novel mode of lipid release by AM fungi.
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Affiliation(s)
- Yoshihiro Kobae
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-8657 Japan
| | - Caroline Gutjahr
- Institute of Genetics, Faculty of Biology, University of Munich (LMU), 82152 Martinsried, Germany
| | - Uta Paszkowski
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Tomoko Kojima
- National Agriculture and Food Research Organization (NARO) Institute of Livestock and Grassland Science, 768 Senbonmatsu, Nasushiobara, Tochigi, 329-2793 Japan
| | - Toru Fujiwara
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-8657 Japan
| | - Shingo Hata
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan Ryukoku University, 67 Tsukamoto-cho, Fukakusa, Fushimi-ku, Kyoto, 612-8577 Japan
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Different responses of arbuscular mycorrhizal fungal community to day-time and night-time warming in a semiarid steppe. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11434-014-0602-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kong D, Ma C, Zhang Q, Li L, Chen X, Zeng H, Guo D. Leading dimensions in absorptive root trait variation across 96 subtropical forest species. THE NEW PHYTOLOGIST 2014; 203:863-72. [PMID: 24824672 DOI: 10.1111/nph.12842] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/03/2014] [Indexed: 05/03/2023]
Abstract
Absorptive root traits show remarkable cross-species variation, but major root trait dimensions across species have not been defined. We sampled first-order roots and measured 14 root traits for 96 angiosperm woody species from subtropical China, including root diameter, specific root length, stele diameter, cortex thickness, root vessel size and density, mycorrhizal colonization rate, root branching intensity, tissue density, and concentrations of carbon and nitrogen ([N]). Root traits differed in the degree of variation and phylogenetic conservatism, but showed predictable patterns of cross-trait coordination. Root diameter, cortex thickness and stele diameter displayed high variation across species (coefficient of variation (CV)=0.51-0.69), whereas the stele:root diameter ratio and [N] showed low variation (CV<0.32). Root diameter, cortex thickness and stele diameter showed a strong phylogenetic signal across species, whereas root branching traits did not, and these two sets of traits were segregated onto two nearly orthogonal (independent) principal component analysis (PCA) axes. Two major dimensions of root trait variation were found: a diameter-related dimension potentially integrating root construction, maintenance, and persistence with mycorrhizal colonization, and a branching architecture dimension expressing root plastic responses to the environment. These two dimensions may offer a promising path for better understanding root trait economics and root ecological strategies world-wide.
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Affiliation(s)
- Deliang Kong
- The Key Laboratory for Urban Habitat Environmental Science and Technology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
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