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Wolfe ER, Ballhorn DJ. Do Foliar Endophytes Matter in Litter Decomposition? Microorganisms 2020; 8:microorganisms8030446. [PMID: 32245270 PMCID: PMC7143956 DOI: 10.3390/microorganisms8030446] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/13/2020] [Accepted: 03/19/2020] [Indexed: 11/16/2022] Open
Abstract
Litter decomposition rates are affected by a variety of abiotic and biotic factors, including the presence of fungal endophytes in host plant tissues. This review broadly analyzes the findings of 67 studies on the roles of foliar endophytes in litter decomposition, and their effects on decomposition rates. From 29 studies and 1 review, we compiled a comprehensive table of 710 leaf-associated fungal taxa, including the type of tissue these taxa were associated with and isolated from, whether they were reported as endo- or epiphytic, and whether they had reported saprophytic abilities. Aquatic (i.e., in-stream) decomposition studies of endophyte-affected litter were significantly under-represented in the search results (p < 0.0001). Indicator species analyses revealed that different groups of fungal endophytes were significantly associated with cool or tropical climates, as well as specific plant host genera (p < 0.05). Finally, we argue that host plant and endophyte interactions can significantly influence litter decomposition rates and should be considered when interpreting results from both terrestrial and in-stream litter decomposition experiments.
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Qin J, Wu M, Liu H, Gao Y, Ren A. Endophyte Infection and Methyl Jasmonate Treatment Increased the Resistance of Achnatherum sibiricum to Insect Herbivores Independently. Toxins (Basel) 2018; 11:toxins11010007. [PMID: 30587763 PMCID: PMC6357071 DOI: 10.3390/toxins11010007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/26/2022] Open
Abstract
Alkaloids are usually thought to be responsible for protecting endophyte-infected (EI) grasses from their herbivores. For EI grasses that produce few alkaloids, can endophyte infection enhance their resistance to herbivores? Related studies are limited. In the Inner Mongolian steppe, Achnatherum sibiricum is highly infected by Epichloë endophytes, but produces few alkaloids. Locusts are the common insect herbivores of grasses. In this study, A. sibiricum was used as plant material. Methyl jasmonate (MJ, when applied exogenously, can induce responses similar to herbivore damage) treatment was performed. The effects of endophyte infection and MJ treatment on the resistance of A. sibiricum to Locusta migratoria were studied. We found that locusts preferred EF (endophyte-free) plants to EI plants in both choice and no-choice feeding experiments. Endophyte infection enhanced the resistance of A. sibiricum to locusts. Endophyte infection decreased soluble sugar concentrations, while it increased the total phenolic content and phenylalanine ammonia lyase (PAL) activity, which may contribute to the resistance of A. sibiricum to locusts. There was an interaction effect between MJ treatment and endophyte infection on the growth of the host. MJ treatment was a negative regulator of the plant growth-promoting effects of endophyte infection. There was no interaction effect between MJ treatment and endophyte infection on the defense characteristics of the host. In groups not exposed to locusts, MJ treatment and endophyte infection had a similar effect in decreasing the soluble sugar content, while increasing the total phenolic content and the PAL activity. In groups exposed to locusts, the effect of MJ treatment on the above characteristics disappeared, while the effect of endophyte infection became more obvious. All of these results suggest that even for endophytes producing few alkaloids, they could still increase the resistance of native grasses to insect herbivores. Furthermore, endophyte infection might mediate the defense responses of the host, independent of jasmonic acid (JA) pathways.
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Affiliation(s)
- Junhua Qin
- College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Man Wu
- College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Hui Liu
- College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Yubao Gao
- College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Anzhi Ren
- College of Life Sciences, Nankai University, Tianjin 300071, China.
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Sneck ME, Rudgers JA, Young CA, Miller TEX. Variation in the Prevalence and Transmission of Heritable Symbionts Across Host Populations in Heterogeneous Environments. MICROBIAL ECOLOGY 2017; 74:640-653. [PMID: 28314899 DOI: 10.1007/s00248-017-0964-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/09/2017] [Indexed: 05/29/2023]
Abstract
Heritable microbes are abundant in nature and influential to their hosts and the communities in which they reside. However, drivers of variability in the prevalence of heritable symbionts and their rates of transmission are poorly resolved, particularly across host populations experiencing variable biotic and abiotic environments. To fill these gaps, we surveyed 25 populations of two native grasses (Elymus virginicus and Elymus canadensis) across the southern Great Plains (USA). Both grass species host heritable endophytic fungi (genus Epichloё) and can hybridize where their ranges overlap. From a subset of hosts, we characterized endophyte genotype using genetic loci that link to bioactive alkaloid production. First, we found mean vertical transmission rates and population-level prevalence were positively correlated, specifically for E. virginicus. However, both endophyte prevalence and transmission varied substantially across populations and did not strongly correlate with abiotic variables, with one exception: endophyte prevalence decreased as drought stress decreased for E. virginicus hosts. Second, we evaluated the potential influence of biotic factors and found that, after accounting for climate, endophyte genotype explained significant variation in symbiont inheritance. We also contrasted populations where host species co-occurred in sympatry vs. allopatry. Sympatry could potentially increase interspecific hybridization, but this variable did not associate with patterns of symbiont prevalence or transmission success. Our results reveal substantial variability in symbiont prevalence and transmission across host populations and identify symbiont genotype, and to a lesser extent, the abiotic environment as sources of this variation.
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Affiliation(s)
- Michelle E Sneck
- Department of BioSciences, Program in Ecology and Evolutionary Biology, Rice University, 6100 Main Street, Houston, TX, 77005, USA.
| | - Jennifer A Rudgers
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Carolyn A Young
- Samuel Roberts Noble Foundation, Inc, Ardmore, OK, 73401, USA
| | - Tom E X Miller
- Department of BioSciences, Program in Ecology and Evolutionary Biology, Rice University, 6100 Main Street, Houston, TX, 77005, USA
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Qin J, Gao Y, Liu H, Zhou Y, Ren A, Gao Y. Effect of Endophyte Infection and Clipping Treatment on Resistance and Tolerance of Achnatherum sibiricum. Front Microbiol 2016; 7:1988. [PMID: 28018319 PMCID: PMC5156843 DOI: 10.3389/fmicb.2016.01988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/28/2016] [Indexed: 12/24/2022] Open
Abstract
It is well-documented that endophytes can enhance the resistance of agronomical grasses, such as tall fescue and perennial ryegrass to herbivory. For native grasses, however, the related reports are limited, and the conclusions are variable. Achnatherum sibiricum is a grass native to the Inner Mongolian steppe. This grass is highly infected by endophytes but does not produce detectable endophyte-related alkaloids known under normal conditions. In this study, the contributions of endophytes to the resistance of A. sibiricum to Locusta migratoria were studied. We found that locusts preferred EF (endophyte-free) plants to EI (endophyte-infected) plants, and the weight of locusts fed on EI plants was significantly lower than those fed on EF plants. Hence, endophyte infection significantly enhanced the resistance of the host to L. migratoria. Endophyte infection significantly decreased the concentration of soluble sugar and amino acids while significantly increased the concentration of total phenolic content, and these metabolites may contribute to herbivore resistance of the host. The clipping treatment further strengthened the locust resistance advantage of EI over EF plants. After clipping, the weight of the locusts fed on EI plants significantly decreased compared with those fed on unclipped plants, whereas the weight of the locusts fed on EF plants increased significantly. The results suggested that endophyte infection could increase herbivore resistance while decreasing the tolerance of the host grass by mechanisms apart from endophyte-conferred alkaloid defense.
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Affiliation(s)
- Junhua Qin
- College of Life Sciences Nankai University, Tianjin, China
| | - Yuan Gao
- College of Life Sciences Nankai University, Tianjin, China
| | - Hui Liu
- College of Life Sciences Nankai University, Tianjin, China
| | - Yong Zhou
- College of Life Sciences Nankai University, Tianjin, China
| | - Anzhi Ren
- College of Life Sciences Nankai University, Tianjin, China
| | - Yubao Gao
- College of Life Sciences Nankai University, Tianjin, China
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Afkhami ME, Strauss SY. Native fungal endophytes suppress an exotic dominant and increase plant diversity over small and large spatial scales. Ecology 2016; 97:1159-69. [DOI: 10.1890/15-1166.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Michelle E. Afkhami
- Department of Biology University of Miami 1301 Memorial Drive #215 Coral Gables Florida 33146 USA
- Department of Evolution and Ecology University of California, Davis One Shields Avenue 2320 Storer Hall Davis California 95616 USA
| | - Sharon Y. Strauss
- Department of Evolution and Ecology University of California, Davis One Shields Avenue 2320 Storer Hall Davis California 95616 USA
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Yao X, Christensen MJ, Bao G, Zhang C, Li X, Li C, Nan Z. A toxic endophyte-infected grass helps reverse degradation and loss of biodiversity of over-grazed grasslands in northwest China. Sci Rep 2015; 5:18527. [PMID: 26679518 PMCID: PMC4683511 DOI: 10.1038/srep18527] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 11/19/2015] [Indexed: 12/05/2022] Open
Abstract
Overgrazing of China’s grasslands is increasingly causing biodiversity to decline. In degenerated grasslands of northwest China endophyte (Epichloё gansuensis) infected Achnatherum inebrians (drunken horse grass) is becoming widely distributed because of its toxicity to livestock. In this study, we investigated the ecological consequences of endophyte toxicity in this native grass, at three sites in northwest China, by comparing seed production of plant species and arthropod abundance in overgrazed grasslands with and without the presence of A. inebrians. Our findings demonstrate that the presence of endophyte infected A. inebrians reduces the loss of plant and arthropod biodiversity by providing a protected nursery free of animal grazing. Therefore, A. inebrians, typically regarded as an unwanted toxic invader by pastoralists, should be viewed as beneficial for grasslands as its presence maintains plant and arthropod biodiversity, and provides a foundation stone in the reconstruction and restoration of these grassland ecosystems.
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Affiliation(s)
- Xiang Yao
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Michael J Christensen
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Gensheng Bao
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Chunping Zhang
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Xiuzhang Li
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Chunjie Li
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
| | - Zhibiao Nan
- The State Key Laboratory of Grassland Agro-ecosystems; College of Pastoral Agriculture Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, Gansu, China
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Shukla K, Hager HA, Yurkonis KA, Newman JA. Effects of the Epichloë fungal endophyte symbiosis with Schedonorus pratensis on host grass invasiveness. Ecol Evol 2015; 5:2596-607. [PMID: 26257873 PMCID: PMC4523356 DOI: 10.1002/ece3.1536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/20/2015] [Accepted: 04/26/2015] [Indexed: 11/08/2022] Open
Abstract
Initial studies of grass-endophyte mutualisms using Schedonorus arundinaceus cultivar Kentucky-31 infected with the vertically transmitted endophyte Epichloë coenophiala found strong, positive endophyte effects on host-grass invasion success. However, more recent work using different cultivars of S. arundinaceus has cast doubt on the ubiquity of this effect, at least as it pertains to S. arundinaceus-E. coenophiala. We investigated the generality of previous work on vertically transmitted Epichloë-associated grass invasiveness by studying a pair of very closely related species: S. pratensis and E. uncinata. Seven cultivars of S. pratensis and two cultivars of S. arundinaceus that were developed with high- or low-endophyte infection rate were broadcast seeded into 2 × 2-m plots in a tilled, old-field grassland community in a completely randomized block design. Schedonorus abundance, endophyte infection rate, and co-occurring vegetation were sampled 3, 4, 5, and 6 years after establishment, and the aboveground invertebrate community was sampled in S. pratensis plots 3 and 4 years after establishment. Endophyte infection did not enable the host grass to achieve high abundance in the plant community. Contrary to expectations, high-endophyte S. pratensis increased plant richness relative to low-endophyte cultivars. However, as expected, high-endophyte S. pratensis marginally decreased invertebrate taxon richness. Endophyte effects on vegetation and invertebrate community composition were inconsistent among cultivars and were weaker than temporal effects. The effect of the grass-Epichloë symbiosis on diversity is not generalizable, but rather specific to species, cultivar, infection, and potentially site. Examining grass-endophyte systems using multiple cultivars and species replicated among sites will be important to determine the range of conditions in which endophyte associations benefit host grass performance and have subsequent effects on co-occurring biotic communities.
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Affiliation(s)
- Kruti Shukla
- School of Environmental Sciences, University of Guelph Guelph, Ontario, Canada, N1G 2W1
| | - Heather A Hager
- School of Environmental Sciences, University of Guelph Guelph, Ontario, Canada, N1G 2W1
| | - Kathryn A Yurkonis
- Department of Biology, University of North Dakota Grand Forks, North Dakota, USA, 58202
| | - Jonathan A Newman
- School of Environmental Sciences, University of Guelph Guelph, Ontario, Canada, N1G 2W1
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García Parisi P, Grimoldi A, Omacini M. Endophytic fungi of grasses protect other plants from aphid herbivory. FUNGAL ECOL 2014. [DOI: 10.1016/j.funeco.2014.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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9
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Lee YB, An SJ, Park CG, Kim J, Han S, Kwak YS. Oak tree canker disease supports arthropod diversity in a natural ecosystem. THE PLANT PATHOLOGY JOURNAL 2014; 30:43-50. [PMID: 25288984 PMCID: PMC4174828 DOI: 10.5423/ppj.oa.09.2013.0093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/01/2013] [Accepted: 11/20/2013] [Indexed: 06/03/2023]
Abstract
Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.
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Affiliation(s)
- Yong-Bok Lee
- Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 600-701, Korea
| | - Su Jung An
- Department of Applied Biology, Gyeongsang National University, Jinju 600-701, Korea
| | - Chung Gyoo Park
- Department of Applied Biology, Gyeongsang National University, Jinju 600-701, Korea
| | - Jinwoo Kim
- Department of Applied Biology, Gyeongsang National University, Jinju 600-701, Korea
| | - Sangjo Han
- Bioinformatics Lab, SK Telecom, Sungnam 463-784, Korea
| | - Youn-Sig Kwak
- Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 600-701, Korea
- Department of Applied Biology, Gyeongsang National University, Jinju 600-701, Korea
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Saari S, Richter S, Robbins M, Faeth SH. Bottom-up regulates top-down: the effects of hybridization of grass endophytes on an aphid herbivore and its generalist predator. OIKOS 2014. [DOI: 10.1111/j.1600-0706.2013.00690.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Chemical Ecology Mediated by Fungal Endophytes in Grasses. J Chem Ecol 2013; 39:962-8. [DOI: 10.1007/s10886-013-0310-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/24/2013] [Accepted: 06/05/2013] [Indexed: 12/13/2022]
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12
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Fungal grass endophytes and arthropod communities: lessons from plant defence theory and multitrophic interactions. FUNGAL ECOL 2012. [DOI: 10.1016/j.funeco.2011.09.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Bultman TL, Aguilera A, Sullivan TJ. Influence of fungal isolates infecting tall fescue on multitrophic interactions. FUNGAL ECOL 2012. [DOI: 10.1016/j.funeco.2011.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Whitham TG, Gehring CA, Lamit LJ, Wojtowicz T, Evans LM, Keith AR, Smith DS. Community specificity: life and afterlife effects of genes. TRENDS IN PLANT SCIENCE 2012; 17:271-281. [PMID: 22322002 DOI: 10.1016/j.tplants.2012.01.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/26/2011] [Accepted: 01/09/2012] [Indexed: 05/31/2023]
Abstract
Community-level genetic specificity results when individual genotypes or populations of the same species support different communities. Our review of the literature shows that genetic specificity exhibits both life and afterlife effects; it is a widespread phenomenon occurring in diverse taxonomic groups, aquatic to terrestrial ecosystems, and species-poor to species-rich systems. Such specificity affects species interactions, evolution, ecosystem processes and leads to community feedbacks on the performance of the individuals expressing the traits. Thus, genetic specificity by communities appears to be fundamentally important, suggesting that specificity is a major driver of the biodiversity and stability of the world's ecosystems.
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Affiliation(s)
- Thomas G Whitham
- Department of Biological Sciences and Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ 86011, USA.
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Partida-Martínez LP, Heil M. The microbe-free plant: fact or artifact? FRONTIERS IN PLANT SCIENCE 2011; 2:100. [PMID: 22639622 PMCID: PMC3355587 DOI: 10.3389/fpls.2011.00100] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Accepted: 12/05/2011] [Indexed: 05/03/2023]
Abstract
Plant-microbe interactions are ubiquitous. Plants are threatened by pathogens, but they are even more commonly engaged in neutral or mutualistic interactions with microbes: belowground microbial plant associates are mycorrhizal fungi, Rhizobia, and plant-growth promoting rhizosphere bacteria, aboveground plant parts are colonized by internally living bacteria and fungi (endophytes) and by microbes in the phyllosphere (epiphytes). We emphasize here that a completely microbe-free plant is an exotic exception rather than the biologically relevant rule. The complex interplay of such microbial communities with the host-plant affects multiple vital parameters such as plant nutrition, growth rate, resistance to biotic and abiotic stressors, and plant survival and distribution. The mechanisms involved reach from direct ones such as nutrient acquisition, the production of plant hormones, or direct antibiosis, to indirect ones that are mediated by effects on host resistance genes or via interactions at higher trophic levels. Plant-associated microbes are heterotrophic and cause costs to their host plant, whereas the benefits depend on the current environment. Thus, the outcome of the interaction for the plant host is highly context dependent. We argue that considering the microbe-free plant as the "normal" or control stage significantly impairs research into important phenomena such as (1) phenotypic and epigenetic plasticity, (2) the "normal" ecological outcome of a given interaction, and (3) the evolution of plants. For the future, we suggest cultivation-independent screening methods using direct PCR from plant tissue of more than one fungal and bacterial gene to collect data on the true microbial diversity in wild plants. The patterns found could be correlated to host species and environmental conditions, in order to formulate testable hypotheses on the biological roles of plant endophytes in nature. Experimental approaches should compare different host-endophyte combinations under various relevant environmental conditions and study at the genetic, epigenetic, transcriptional, and physiological level the parameters that cause the interaction to shift along the mutualism-parasitism continuum.
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Affiliation(s)
- Laila P. Partida-Martínez
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados – IrapuatoIrapuato, México
| | - Martin Heil
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados – IrapuatoIrapuato, México
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Poelman EH, Gols R, Snoeren TAL, Muru D, Smid HM, Dicke M. Indirect plant-mediated interactions among parasitoid larvae. Ecol Lett 2011; 14:670-6. [DOI: 10.1111/j.1461-0248.2011.01629.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Vesterlund SR, Helander M, Faeth SH, Hyvönen T, Saikkonen K. Environmental conditions and host plant origin override endophyte effects on invertebrate communities. FUNGAL DIVERS 2011. [DOI: 10.1007/s13225-011-0089-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Faeth SH, Hayes CJ, Gardner DR. Asexual endophytes in a native grass: tradeoffs in mortality, growth, reproduction, and alkaloid production. MICROBIAL ECOLOGY 2010; 60:496-504. [PMID: 20195591 DOI: 10.1007/s00248-010-9643-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 02/08/2010] [Indexed: 05/28/2023]
Abstract
Neotyphodium endophytes are asexual, seed-borne fungal symbionts that are thought to interact mutualistically with their grass hosts. Benefits include increased growth, reproduction, and resistance to herbivores via endophytic alkaloids. Although these benefits are well established in infected introduced, agronomic grasses, little is known about the cost and benefits of endophyte infection in native grass populations. These populations exist as mosaics of uninfected and infected plants, with the latter often comprised of plants that vary widely in alkaloid content. We tested the costs and benefits of endophyte infections with varying alkaloids in the native grass Achnatherum robustum (sleepygrass). We conducted a 4-year field experiment, where herbivory and water availability were controlled and survival, growth, and reproduction of three maternal plant genotypes [uninfected plants (E-), infected plants with high levels of ergot alkaloids (E+A+), and infected plants with no alkaloids (E+A-)] were monitored over three growing seasons. Generally, E+A+ plants had reduced growth over the three growing seasons and lower seed production than E- or E+A- plants, suggesting a cost of alkaloid production. The reduction in vegetative biomass in E+A+ plants was most pronounced under supplemented water, contrary to the prediction that additional resources would offset the cost of alkaloid production. Also, E+A+ plants showed no advantage in growth, seed production, or reproductive effort under full herbivory relative to E- or E+A- grasses, contrary to the predictions of the defensive mutualism hypothesis. However, E+A+ plants had higher overwintering survival than E+A- plants in early plant ontogeny, suggesting that alkaloids associated with infection may protect against below ground herbivory or harsh winter conditions. Our results suggest that the mosaic of E-, E+A+, and E+A- plants observed in nature may result from varying biotic and abiotic selective factors that maintain the presence of uninfected plants and infected plants that vary in alkaloid production.
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Affiliation(s)
- Stanley H Faeth
- Department of Biology, The University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
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19
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Rohlfs M, Churchill ACL. Fungal secondary metabolites as modulators of interactions with insects and other arthropods. Fungal Genet Biol 2010; 48:23-34. [PMID: 20807586 DOI: 10.1016/j.fgb.2010.08.008] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/05/2010] [Accepted: 08/22/2010] [Indexed: 12/19/2022]
Abstract
Fungi share a diverse co-evolutionary history with animals, especially arthropods. In this review, we focus on the role of secondary metabolism in driving antagonistic arthropod-fungus interactions, i.e., where fungi serve as a food source to fungal grazers, compete with saprophagous insects, and attack insects as hosts for growth and reproduction. Although a wealth of studies on animal-fungus interactions point to a crucial role of secondary metabolites in deterring animal feeding and resisting immune defense strategies, causal evidence often remains to be provided. Moreover, it still remains an unresolved puzzle as to what extent the tight regulatory control of secondary metabolite formation in some model fungi represents an evolved chemical defense system favored by selective pressure through animal antagonists. Given these gaps in knowledge, we highlight some co-evolutionary aspects of secondary metabolism, such as induced response, volatile signaling, and experimental evolution, which may help in deciphering the ecological importance and evolutionary history of secondary metabolite production in fungi.
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Affiliation(s)
- Marko Rohlfs
- J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August University of Göttingen, Germany.
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Faeth SH. Occam's razor cuts both ways: endophytes, resource allocation, herbivory, and mutualism: a reply to Rudgers et al. Am Nat 2010; 176:104-10. [PMID: 20500039 DOI: 10.1086/652997] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Stanley H Faeth
- Department of Biology, University of North Carolina, Greensboro, North Carolina 27402, USA.
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