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Tapia AC, Jaromczyk JW, Moore N, Schardl CL. RNA-clique: a method for computing genetic distances from RNA-seq data. BMC Bioinformatics 2024; 25:205. [PMID: 38834962 DOI: 10.1186/s12859-024-05811-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 05/15/2024] [Indexed: 06/06/2024] Open
Abstract
BACKGROUND Although RNA-seq data are traditionally used for quantifying gene expression levels, the same data could be useful in an integrated approach to compute genetic distances as well. Challenges to using mRNA sequences for computing genetic distances include the relatively high conservation of coding sequences and the presence of paralogous and, in some species, homeologous genes. RESULTS We developed a new computational method, RNA-clique, for calculating genetic distances using assembled RNA-seq data and assessed the efficacy of the method using biological and simulated data. The method employs reciprocal BLASTn followed by graph-based filtering to ensure that only orthologous genes are compared. Each vertex in the graph constructed for filtering represents a gene in a specific sample under comparison, and an edge connects a pair of vertices if the genes they represent are best matches for each other in their respective samples. The distance computation is a function of the BLAST alignment statistics and the constructed graph and incorporates only those genes that are present in some complete connected component of this graph. As a biological testbed we used RNA-seq data of tall fescue (Lolium arundinaceum), an allohexaploid plant ( 2 n = 14 Gb ), and bluehead wrasse (Thalassoma bifasciatum), a teleost fish. RNA-clique reliably distinguished individual tall fescue plants by genotype and distinguished bluehead wrasse RNA-seq samples by individual. In tests with simulated RNA-seq data, the ground truth phylogeny was accurately recovered from the computed distances. Moreover, tests of the algorithm parameters indicated that, even with stringent filtering for orthologs, sufficient sequence data were retained for the distance computations. Although comparisons with an alternative method revealed that RNA-clique has relatively high time and memory requirements, the comparisons also showed that RNA-clique's results were at least as reliable as the alternative's for tall fescue data and were much more reliable for the bluehead wrasse data. CONCLUSION Results of this work indicate that RNA-clique works well as a way of deriving genetic distances from RNA-seq data, thus providing a methodological integration of functional and genetic diversity studies.
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Affiliation(s)
- Andrew C Tapia
- Department of Computer Science, University of Kentucky, 329 Rose St, Lexington, KY, 40508, USA.
| | - Jerzy W Jaromczyk
- Department of Computer Science, University of Kentucky, 329 Rose St, Lexington, KY, 40508, USA
| | - Neil Moore
- Department of Computer Science, University of Kentucky, 329 Rose St, Lexington, KY, 40508, USA
| | - Christopher L Schardl
- Department of Plant Pathology, University of Kentucky, 1405 Veterans Dr, Lexington, KY, 40546, USA
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Realini FM, Escobedo VM, Ueno AC, Bastías DA, Schardl CL, Biganzoli F, Gundel PE. Anti-herbivory defences delivered by Epichloë fungal endophytes: a quantitative review of alkaloid concentration variation among hosts and plant parts. ANNALS OF BOTANY 2024; 133:509-520. [PMID: 38320313 PMCID: PMC11037487 DOI: 10.1093/aob/mcae014] [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: 01/16/2024] [Accepted: 02/01/2024] [Indexed: 02/08/2024]
Abstract
BACKGROUND AND AIMS In the subfamily Poöideae (Poaceae), certain grass species possess anti-herbivore alkaloids synthesized by fungal endophytes that belong to the genus Epichloë (Clavicipitaceae). The protective role of these symbiotic endophytes can vary, depending on alkaloid concentrations within specific plant-endophyte associations and plant parts. METHODS We conducted a literature review to identify articles containing alkaloid concentration data for various plant parts in six important pasture species, Lolium arundinaceum, Lolium perenne, Lolium pratense, Lolium multiflorum|Lolium rigidum and Festuca rubra, associated with their common endophytes. We considered the alkaloids lolines (1-aminopyrrolizidines), peramine (pyrrolopyrazines), ergovaline (ergot alkaloids) and lolitrem B (indole-diterpenes). While all these alkaloids have shown bioactivity against insect herbivores, ergovaline and lolitrem B are harmful for mammals. KEY RESULTS Loline alkaloid levels were higher in the perennial grasses L. pratense and L. arundinaceum compared to the annual species L. multiflorum and L. rigidum, and higher in reproductive tissues than in vegetative structures. This is probably due to the greater biomass accumulation in perennial species that can result in higher endophyte mycelial biomass. Peramine concentrations were higher in L. perenne than in L. arundinaceum and not affected by plant part. This can be attributed to the high within-plant mobility of peramine. Ergovaline and lolitrem B, both hydrophobic compounds, were associated with plant parts where fungal mycelium is usually present, and their concentrations were higher in plant reproductive tissues. Only loline alkaloid data were sufficient for below-ground tissue analyses and concentrations were lower than in above-ground parts. CONCLUSIONS Our study provides a comprehensive synthesis of fungal alkaloid variation across host grasses and plant parts, essential for understanding the endophyte-conferred defence extent. The patterns can be understood by considering endophyte growth within the plant and alkaloid mobility. Our study identifies research gaps, including the limited documentation of alkaloid presence in roots and the need to investigate the influence of different environmental conditions.
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Affiliation(s)
- Florencia M Realini
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Departamento de Ecología, Genética y Evolución, Laboratorio de Citogenética y Evolución (LaCyE), Ciudad Autónoma de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Ecología, Genética y Evolución (IEGEBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Víctor M Escobedo
- Instituto de Investigación Interdisciplinaria (I3), Universidad de Talca, Campus Talca, Chile
- Centro de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Andrea C Ueno
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Instituto de Investigación Interdisciplinaria (I3), Universidad de Talca, Campus Talca, Chile
- Centro de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Daniel A Bastías
- AgResearch Limited, Grasslands Research Centre, Palmerston North 4442, New Zealand
| | | | - Fernando Biganzoli
- Departamento de Métodos Cuantitativos y Sistemas de Información, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pedro E Gundel
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Centro de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
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Bogas AC, Cruz FPN, Lacava PT, Sousa CP. Endophytic fungi: an overview on biotechnological and agronomic potential. BRAZ J BIOL 2024; 84:e258557. [DOI: 10.1590/1519-6984.258557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/08/2022] [Indexed: 11/22/2022] Open
Abstract
Abstract Endophytic fungi colonize the inter- and/or intracellular regions of healthy plant tissues and have a close symbiotic relationship with their hosts. These microorganisms produce antibiotics, enzymes, and other bioactive compounds that enable them to survive in competitive habitats with other microorganisms. In addition, secondary metabolites confer protection to their host plant against other bacterial and fungal pathogens and/or can promote plant growth. Endophytic fungi are viewed as a promising source of bioactive natural products, which can be optimized through changes in growing conditions. The exploration of novel bioactive molecules produced by these microorganisms has been attracting attention from researchers. The chemical and functional diversity of natural products from endophytic fungi exhibits a broad spectrum of applications in medicine, agriculture, industry and the environment. Fungal endophytes can also enhance the photoprotective effects and photochemical efficiency in the host plants. Modern omic approaches have facilitated research investigating symbiotic plant-endophytic fungi interactions. Therefore, research on endophytic fungi can help discovery novel biomolecules for various biotechnological applications and develop a sustainable agriculture.
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Forte FP, Malinowska M, Nagy I, Schmid J, Dijkwel P, Hume DE, Johnson RD, Simpson WR, Asp T. Methylome changes in Lolium perenne associated with long-term colonisation by the endophytic fungus Epichloë sp. LpTG-3 strain AR37. FRONTIERS IN PLANT SCIENCE 2023; 14:1258100. [PMID: 37810388 PMCID: PMC10557135 DOI: 10.3389/fpls.2023.1258100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023]
Abstract
Epichloë spp. often form mutualistic interactions with cool-season grasses, such as Lolium perenne. However, the molecular mechanisms underlying this interaction remain poorly understood. In this study, we employed reduced representation bisulfite sequencing method (epiGBS) to investigate the impact of the Epichloë sp. LpTG-3 strain AR37 on the methylome of L. perenne across multiple grass generations and under drought stress conditions. Our results showed that the presence of the endophyte leads to a decrease in DNA methylation across genomic features, with differentially methylated regions primarily located in intergenic regions and CHH contexts. The presence of the endophyte was consistently associated with hypomethylation in plants across generations. This research sheds new light on the molecular mechanisms governing the mutualistic interaction between Epichloë sp. LpTG-3 strain AR37 and L. perenne. It underscores the role of methylation changes associated with endophyte infection and suggests that the observed global DNA hypomethylation in L. perenne may be influenced by factors such as the duration of the endophyte-plant association and the accumulation of genetic and epigenetic changes over time.
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Affiliation(s)
- Flavia Pilar Forte
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Aarhus, Denmark
| | - Marta Malinowska
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Aarhus, Denmark
| | - Istvan Nagy
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Aarhus, Denmark
| | - Jan Schmid
- Ferguson Street Laboratories, Palmerston North, New Zealand
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Paul Dijkwel
- Ferguson Street Laboratories, Palmerston North, New Zealand
| | - David E. Hume
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Wayne R. Simpson
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - Torben Asp
- Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Aarhus, Denmark
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Rahnama M, Maclean P, Fleetwood DJ, Johnson RD. Comparative Transcriptomics Profiling of Perennial Ryegrass Infected with Wild Type or a Δ velA Epichloë festucae Mutant Reveals Host Processes Underlying Mutualistic versus Antagonistic Interactions. J Fungi (Basel) 2023; 9:jof9020190. [PMID: 36836305 PMCID: PMC9959145 DOI: 10.3390/jof9020190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 02/05/2023] Open
Abstract
Epichloë species form bioprotective endophytic symbioses with many cool-season grasses, including agriculturally important forage grasses. Despite its importance, relatively little is known about the molecular details of the interaction and the regulatory genes involved. VelA is a key global regulator in fungal secondary metabolism and development. In previous studies, we showed the requirement of velA for E. festucae to form a mutualistic interaction with Lolium perenne. We showed that VelA regulates the expression of genes encoding proteins involved in membrane transport, fungal cell wall biosynthesis, host cell wall degradation, and secondary metabolism, along with several small-secreted proteins in Epichloë festucae. Here, by a comparative transcriptomics analysis on perennial ryegrass seedlings and mature plants, which are endophyte free or infected with wild type (mutualistic interaction) or mutant ΔvelA E. festucae (antagonistic or incompatible interaction), regulatory effects of the endophytic interaction on perennial ryegrass development was studied. We show that ΔvelA mutant associations influence the expression of genes involved in primary metabolism, secondary metabolism, and response to biotic and abiotic stresses compared with wild type associations, providing an insight into processes defining mutualistic versus antagonistic interactions.
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Affiliation(s)
- Mostafa Rahnama
- Department of Biology, Tennessee Tech University, Cookeville, TN 38505, USA
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand
- Correspondence: (M.R.); (R.D.J.)
| | - Paul Maclean
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand
| | | | - Richard D. Johnson
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand
- Correspondence: (M.R.); (R.D.J.)
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Zhan Y, Liu H, Cao Z, Chen W, Li Z, Bai L, Pan L. Comparative analysis of fungal communities between herbicide-resistant and -susceptible Alopecurus aequalis. Front Cell Infect Microbiol 2022; 12:1094853. [PMID: 36619755 PMCID: PMC9816403 DOI: 10.3389/fcimb.2022.1094853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Introduction Alopecurus aequalis is a grass species invading Chinese canola and wheat fields. An A. aequalis KMN-R population surviving mesosulfuron-methyl treatment with recommended rates was acquired from wheatland. Here, we aimed to confirm the resistance profiles of KMN-R to acetolactate synthetase (ALS) inhibiting herbicides and explore the possible resistance mechanisms to mesosulfuron-methyl in this weed population. Methods The dose-response tests performed in our study were used to test the toxicity of A. aequalis to ALS-inhibiting herbicides. Sanger sequencing was used to analyze the ALS gene of mesosulfuron-methyl -resistant and -susceptible A. aequalis. RNA sequencing analysis was used to find candidate genes that may confer metabolic resistance to the mesosulfuron-methyl in resistant A. aequalis population. Mesosulfuron-methyl -resistant and -susceptible A. aequalis populations fungal composition was measured via Illumina MiSeq Sequencing. Results Dose-response results indicated that KMN-R population evolved resistance to mesosulfuron-methyl and other tested ALS-inhibiting herbicides. Known resistance-conferring Trp-574-Leu gene mutation in A. aequalis ALS was detected in the KMN-R population. Pretreatment with 4-chloro-7-nitrobenzoxadiazole reversed mesosulfuron-methyl resistance in KMN-R. Glutathione S-transferases (GST) gene GSTZ2 and GSTT3 were highly expressed in KMN-R population. In addition, we evaluated the alpha diversity in A. aequalis, centering on OTU abundance, equality, and multiplicity, and found that the fungal community composition had more unexplained variance between KMN-R and KMN-S A. aequalis. We also observed higher abundances of specific fungi in KMN-R A. aequalis. Discussion The results proved that resistance to mesosulfuron-methyl in A. aequalis KMN-R population is probably caused by target site- and non-target site-based relating GST and provided the basis for further research between fungal interaction and herbicide resistance.
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Affiliation(s)
| | | | | | | | | | | | - Lang Pan
- *Correspondence: Lang Pan, ; Lianyang Bai,
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Shi X, Qin T, Qu Y, Zhang J, Hao G, Zhao N, Gao Y, Ren A. Infection by Endophytic Epichloë sibirica Was Associated with Activation of Defense Hormone Signal Transduction Pathways and Enhanced Pathogen Resistance in the Grass Achnatherum sibiricum. PHYTOPATHOLOGY 2022; 112:2310-2320. [PMID: 35704677 DOI: 10.1094/phyto-12-21-0521-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Epichloë endophytes can improve the resistance of host grasses to pathogenic fungi, but the underlying mechanisms remain largely unknown. Here, we used phytohormone quantifications, gene expression analysis, and pathogenicity experiments to investigate the effect of Epichloë sibirica on the resistance of Achnatherum sibiricum to Curvularia lunata pathogens. Comparison of gene expression patterns between endophyte-infected and endophyte-free leaves revealed that endophyte infection was associated with significant induction of 1,758 and 765 differentially expressed genes in the host before and after pathogen inoculation, respectively. Functional analysis of the differentially expressed genes suggested that endophyte infection could activate the constitutive resistance of the host by increasing photosynthesis, enhancing the ability to scavenge reactive oxygen species, and actively regulating the expression of genes with function related to disease resistance. We found that endophyte infection was associated with induction of the expression of genes involved in the biosynthesis pathways of jasmonic acid, ethylene, and pipecolic acid and amplified the defense response of the jasmonic acid/ethylene co-regulated EIN/ERF1 transduction pathway and Pip-mediated TGA transduction pathway. Phytohormone quantifications showed that endophyte infection was associated with significant accumulation of jasmonic acid, ethylene, and pipecolic acid after pathogen inoculation. Exogenous phytohormone treatments confirmed that the disease index of plants was negatively related to both jasmonic acid and ethylene concentrations. Our results demonstrate that endophyte infection can not only improve the constitutive resistance of the host to phytopathogens before pathogen inoculation but also be associated with enhanced systemic resistance of the host to necrotrophs after C. lunata inoculation.
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Affiliation(s)
- Xinjian Shi
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Tianzi Qin
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yaobing Qu
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Junzhen Zhang
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Guang Hao
- College of Life Sciences, Nankai University, Tianjin 300071, China
- College of Environmental Science & Engineering, Nankai University, Tianjin 300071, China
| | - Nianxi Zhao
- 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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Zhang W, Forester NT, Moon CD, Maclean PH, Gagic M, Arojju SK, Card SD, Matthew C, Johnson RD, Johnson LJ, Faville MJ, Voisey CR. Epichloë seed transmission efficiency is influenced by plant defense response mechanisms. FRONTIERS IN PLANT SCIENCE 2022; 13:1025698. [PMID: 36340377 PMCID: PMC9635450 DOI: 10.3389/fpls.2022.1025698] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Asexual Epichloë are endophytic fungi that form mutualistic symbioses with cool-season grasses, conferring to their hosts protection against biotic and abiotic stresses. Symbioses are maintained between grass generations as hyphae are vertically transmitted from parent to progeny plants through seed. However, endophyte transmission to the seed is an imperfect process where not all seeds become infected. The mechanisms underpinning the varying efficiencies of seed transmission are poorly understood. Host gene expression in response to Epichloë sp. LpTG-3 strain AR37 was examined within inflorescence primordia and ovaries of high and low endophyte transmission genotypes within a single population of perennial ryegrass. A genome-wide association study was conducted to identify population-level single nucleotide polymorphisms (SNPs) and associated genes correlated with vertical transmission efficiency. For low transmitters of AR37, upregulation of perennial ryegrass receptor-like kinases and resistance genes, typically associated with phytopathogen detection, comprised the largest group of differentially expressed genes (DEGs) in both inflorescence primordia and ovaries. DEGs involved in signaling and plant defense responses, such as cell wall modification, secondary metabolism, and reactive oxygen activities were also abundant. Transmission-associated SNPs were associated with genes for which gene ontology analysis identified "response to fungus" as the most significantly enriched term. Moreover, endophyte biomass as measured by quantitative PCR of Epichloë non-ribosomal peptide synthetase genes, was significantly lower in reproductive tissues of low-transmission hosts compared to high-transmission hosts. Endophyte seed-transmission efficiency appears to be influenced primarily by plant defense responses which reduce endophyte colonization of host reproductive tissues.
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Affiliation(s)
- Wei Zhang
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Natasha T. Forester
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Christina D. Moon
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Paul H. Maclean
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Milan Gagic
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Sai Krishna Arojju
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Stuart D. Card
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Cory Matthew
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Richard D. Johnson
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Linda J. Johnson
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Marty J. Faville
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Christine R. Voisey
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
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Fardella PA, Tian Z, Clarke BB, Belanger FC. The Epichloë festucae Antifungal Protein Efe-AfpA Protects Creeping Bentgrass ( Agrostis stolonifera) from the Plant Pathogen Clarireedia jacksonii, the Causal Agent of Dollar Spot Disease. J Fungi (Basel) 2022; 8:jof8101097. [PMID: 36294663 PMCID: PMC9605492 DOI: 10.3390/jof8101097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/11/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
Dollar spot disease, caused by the fungal pathogen Clarireedia jacksonii, is a major problem in many turfgrass species, particularly creeping bentgrass (Agrostis stolonifera). It is well-established that strong creeping red fescue (Festuca rubra subsp. rubra) exhibits good dollar spot resistance when infected by the fungal endophyte Epichloë festucae. This endophyte-mediated disease resistance is unique to the fine fescues and has not been observed in other grass species infected with other Epichloë spp. The mechanism underlying the unique endophyte-mediated disease resistance in strong creeping red fescue has not yet been established. We pursued the possibility that it may be due to the presence of an abundant secreted antifungal protein produced by E. festucae. Here, we compare the activity of the antifungal protein expressed in Escherichia coli, Pichia pastoris, and Penicillium chrysogenum. Active protein was recovered from all systems, with the best activity being from Pe. chrysogenum. In greenhouse assays, topical application of the purified antifungal protein to creeping bentgrass and endophyte-free strong creeping red fescue protected the plants from developing severe symptoms caused by C. jacksonii. These results support the hypothesis that Efe-AfpA is a major contributor to the dollar spot resistance observed with E. festucae-infected strong creeping red fescue in the field, and that this protein could be developed as an alternative or complement to fungicides for the management of this disease on turfgrasses.
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Comprehensive Analysis of Transcriptome and Metabolome Elucidates the Molecular Regulatory Mechanism of Salt Resistance in Roots of Achnatherum inebrians Mediated by Epichloë gansuensis. J Fungi (Basel) 2022; 8:jof8101092. [PMID: 36294657 PMCID: PMC9605608 DOI: 10.3390/jof8101092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/15/2022] [Accepted: 10/13/2022] [Indexed: 11/17/2022] Open
Abstract
Salinization of soil is a major environmental risk factor to plant functions, leading to a reduction of productivity of crops and forage. Epichloë gansuensis, seed-borne endophytic fungi, establishes a mutualistic symbiotic relationship with Achnatherum inebrians and confers salt tolerance in the host plants. In this study, analysis of transcriptome and metabolome was used to explore the potential molecular mechanism underlying the salt-adaptation of A. inebrians roots mediated by E. gansuensis. We found that E. gansuensis played an important role in the gene expression of the host’s roots and regulated multiple pathways involved in amino acid metabolism, carbohydrate metabolism, TCA cycle, secondary metabolism, and lipid metabolism in the roots of A. inebrians. Importantly, E. gansuensis significantly induced the biological processes, including exocytosis, glycolytic process, fructose metabolic process, and potassium ion transport in roots of host plants at transcriptional levels, and altered the pathways, including inositol phosphate metabolism, galactose metabolism, starch, and sucrose metabolism at metabolite levels under NaCl stress. These findings provided insight into the molecular mechanism of salt resistance in roots of A. inebrians mediated by E. gansuensis and could drive progress in the cultivation of new salt-resistance breeds with endophytes.
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Chaudhary P, Agri U, Chaudhary A, Kumar A, Kumar G. Endophytes and their potential in biotic stress management and crop production. Front Microbiol 2022; 13:933017. [PMID: 36325026 PMCID: PMC9618965 DOI: 10.3389/fmicb.2022.933017] [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: 04/30/2022] [Accepted: 09/12/2022] [Indexed: 11/21/2022] Open
Abstract
Biotic stress is caused by harmful microbes that prevent plants from growing normally and also having numerous negative effects on agriculture crops globally. Many biotic factors such as bacteria, fungi, virus, weeds, insects, and nematodes are the major constrains of stress that tends to increase the reactive oxygen species that affect the physiological and molecular functioning of plants and also led to the decrease in crop productivity. Bacterial and fungal endophytes are the solution to overcome the tasks faced with conventional farming, and these are environment friendly microbial commodities that colonize in plant tissues without causing any damage. Endophytes play an important role in host fitness, uptake of nutrients, synthesis of phytohormone and diminish the injury triggered by pathogens via antibiosis, production of lytic enzymes, secondary metabolites, and hormone activation. They are also reported to help plants in coping with biotic stress, improving crops and soil health, respectively. Therefore, usage of endophytes as biofertilizers and biocontrol agent have developed an eco-friendly substitute to destructive chemicals for plant development and also in mitigation of biotic stress. Thus, this review highlighted the potential role of endophytes as biofertilizers, biocontrol agent, and in mitigation of biotic stress for maintenance of plant development and soil health for sustainable agriculture.
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Affiliation(s)
- Parul Chaudhary
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Upasana Agri
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | | | - Ashish Kumar
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Govind Kumar
- Indian Council of Agricultural Research (ICAR)-Central Institute for Subtropical Horticulture, Lucknow, India
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Ahmad I, Jiménez-Gasco MDM, Luthe DS, Barbercheck ME. Endophytic Metarhizium robertsii suppresses the phytopathogen, Cochliobolus heterostrophus and modulates maize defenses. PLoS One 2022; 17:e0272944. [PMID: 36137142 PMCID: PMC9499252 DOI: 10.1371/journal.pone.0272944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/31/2022] [Indexed: 11/19/2022] Open
Abstract
Fungi in the genus Metarhizium (Hypocreales: Clavicipitaceae) are insect-pathogens and endophytes that can benefit their host plant through growth promotion and protection against stresses. Cochliobolus heterostrophus (Drechsler) Drechsler (Pleosporales: Pleosporaceae) is an economically-significant phytopathogenic fungus that causes Southern Corn Leaf Blight (SCLB) in maize. We conducted greenhouse and lab-based experiments to determine the effects of endophytic M. robertsii J.F. Bisch., Rehner & Humber on growth and defense in maize (Zea mays L.) infected with C. heterostrophus. We inoculated maize seeds with spores of M. robertsii and, at the 3 to 4-leaf stage, the youngest true leaf of M. robertsii-treated and untreated control plants with spores of C. heterostrophus. After 96 h, we measured maize height, above-ground biomass, endophytic colonization by M. robertsii, severity of SCLB, and expression of plant defense genes and phytohormone content. We recovered M. robertsii from 74% of plants grown from treated seed. The severity of SCLB in M. robertsii-treated maize plants was lower than in plants inoculated only with C. heterostrophus. M. robertsii-treated maize inoculated or not inoculated with C. heterostrophus showed greater height and above-ground biomass compared with untreated control plants. Height and above-ground biomass of maize co-inoculated with M. robertsii and C. heterostrophus were not different from M. robertsii-treated maize. M. robertsii modulated the expression of defense genes and the phytohormone content in maize inoculated with C. heterostrophus compared with plants not inoculated with C. heterostrophus and control plants. These results suggest that endophytic M. robertsii can promote maize growth and reduce development of SCLB, possibly by induced systemic resistance mediated by modulation of phytohormones and expression of defense and growth-related genes in maize.
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Affiliation(s)
- Imtiaz Ahmad
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (MEB); (IA)
| | - María del Mar Jiménez-Gasco
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Dawn S. Luthe
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Mary E. Barbercheck
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (MEB); (IA)
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13
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Zhou J, Huang PW, Li X, Vaistij FE, Dai CC. Generalist endophyte Phomopsis liquidambaris colonization of Oryza sativa L. promotes plant growth under nitrogen starvation. PLANT MOLECULAR BIOLOGY 2022; 109:703-715. [PMID: 35522401 DOI: 10.1007/s11103-022-01268-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Fungal endophytes establish symbiotic relationships with host plants, which results in a mutual growth benefit. However, little is known about the plant genetic response underpinning endophyte colonization. Phomopsis liquidambaris usually lives as an endophyte in a wide range of asymptomatic hosts and promotes biotic and abiotic stress resistance. In this study, we show that under low nitrogen conditions P. liquidambaris promotes rice growth in a hydroponic system, which is free of other microorganisms. In order to gain insights into the mechanisms of plant colonization by P. liquidambaris under low nitrogen conditions, we compared root and shoot transcriptome profiles of root-inoculated rice at different colonization stages. We determined that genes related to plant growth promotion, such as gibberellin and auxin related genes, were up-regulated at all developmental stages both locally and systemically. The largest group of up-regulated genes (in both roots and shoots) were related to flavonoid biosynthesis, which is involved in plant growth as well as antimicrobial compounds. Furthermore, genes encoding plant defense-related endopeptidase inhibitors were strongly up-regulated at the early stage of colonization. Together, these results provide new insights into the molecular mechanisms of plant-microbe mutualism and the promotion of plant growth by a fungal endophyte under nitrogen-deficient conditions.
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Affiliation(s)
- Jun Zhou
- Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, 210023, Nanjing, China
- Centre for Novel Agricultural Products, Department of Biology, University of York, YO10 5DD, York, United Kingdom
| | - Peng-Wei Huang
- Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, 210023, Nanjing, China
| | - Xin Li
- Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, 210023, Nanjing, China
| | - Fabián E Vaistij
- Centre for Novel Agricultural Products, Department of Biology, University of York, YO10 5DD, York, United Kingdom
| | - Chuan-Chao Dai
- Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, 210023, Nanjing, China.
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14
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Islam MS, Krom N, Kwon T, Li G, Saha MC. Transcriptome of Endophyte-Positive and Endophyte-Free Tall Fescue Under Field Stresses. FRONTIERS IN PLANT SCIENCE 2022; 13:803400. [PMID: 35774806 PMCID: PMC9237612 DOI: 10.3389/fpls.2022.803400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Tall fescue is one of the primary sources of forage for livestock. It grows well in the marginal soils of the temperate zones. It hosts a fungal endophyte (Epichloë coenophiala), which helps the plants to tolerate abiotic and biotic stresses. The genomic and transcriptomic resources of tall fescue are very limited, due to a complex genetic background and outbreeding modes of pollination. The aim of this study was to identify differentially expressed genes (DEGs) in two tissues (pseudostem and leaf blade) between novel endophyte positive (E+) and endophyte-free (E-) Texoma MaxQ II tall fescue genotypes. Samples were collected at three diurnal time points: morning (7:40-9:00 am), afternoon (1:15-2:15 pm), and evening (4:45-5:45 pm) in the field environment. By exploring the transcriptional landscape via RNA-seq, for the first time, we generated 226,054 and 224,376 transcripts from E+ and E- tall fescue, respectively through de novo assembly. The upregulated transcripts were detected fewer than the downregulated ones in both tissues (S: 803 up and 878 down; L: 783 up and 846 down) under the freezing temperatures (-3.0-0.5°C) in the morning. Gene Ontology enrichment analysis identified 3 out of top 10 significant GO terms only in the morning samples. Metabolic pathway and biosynthesis of secondary metabolite genes showed lowest number of DEGs under morning freezing stress and highest number in evening cold condition. The 1,085 DEGs were only expressed under morning stress condition and, more importantly, the eight candidate orthologous genes of rice identified under morning freezing temperatures, including orthologs of rice phytochrome A, phytochrome C, and ethylene receptor genes, might be the possible route underlying cold tolerance in tall fescue.
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Affiliation(s)
- Md. Shofiqul Islam
- Grass Genomics, Noble Research Institute LLC, Ardmore, OK, United States
- Genetics Laboratory, Indiana Crop Improvement Association, Lafayette, IN, United States
| | - Nick Krom
- Scientific Computing, Noble Research Institute LLC, Ardmore, OK, United States
| | - Taegun Kwon
- Genomics Core Facility, Noble Research Institute LLC, Ardmore, OK, United States
- Genomics Center, BioDiscovery Institute, University of North Texas, Denton, TX, United States
| | - Guifen Li
- Genomics Core Facility, Noble Research Institute LLC, Ardmore, OK, United States
| | - Malay C. Saha
- Grass Genomics, Noble Research Institute LLC, Ardmore, OK, United States
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15
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Nagabhyru P, Dinkins RD, Schardl CL. Transcriptome analysis of Epichloë strains in tall fescue in response to drought stress. Mycologia 2022; 114:697-712. [PMID: 35671366 DOI: 10.1080/00275514.2022.2060008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Epichloë coenophiala, a systemic fungal symbiont (endophyte) of tall fescue (Lolium arundinaceum), has been documented to confer to this grass better persistence than plants lacking the endophyte, especially under stress conditions such as drought. The response, if any, of the endophyte to imposition of stress on the host plant has not been characterized previously. Therefore, we investigated effects on gene expression by E. coenophiala and a related endophyte when plant-endophyte symbiota were subjected to acute water-deficit stress. Plants harboring different endophyte strains were grown in sand in the greenhouse, then half were deprived of water for 48 h and the other half were watered controls. RNA was isolated from different plant tissues, and mRNA sequencing (RNA-seq) was conducted to identify genes that were differentially expressed comparing stress treatment with control. We compared two different plants harboring the common toxic E. coenophiala strain (CTE) and two non-ergot-alkaloid-producing Epichloë strains in tall fescue pseudostems, and in a second experiment we compared responses of E. coenophiala CTE in plant pseudostem and crown tissues. The endophytes responded to the stress with increased expression of genes involved in oxidative stress response, oxygen radical detoxification, C-compound carbohydrate metabolism, heat shock, and cellular transport pathways. The magnitude of fungal gene responses during stress varied among plant-endophyte symbiota. Responses in pseudostems and crowns involved some common pathways as well as some tissue-specific pathways. The fungal response to water-deficit stress involved gene expression changes in similar pathways that have been documented for plant stress responses, indicating that Epichloë spp. and their host plants either coordinate stress responses or separately activate similar stress response mechanisms that work together for mutual protection.
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Affiliation(s)
- Padmaja Nagabhyru
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
| | - Randy D Dinkins
- Forage-Animal Production Research Unit, Agricultural Research Service, United States Department of Agriculture, Lexington, Kentucky 40546
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16
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Chakrabarti M, Nagabhyru P, Schardl CL, Dinkins RD. Differential gene expression in tall fescue tissues in response to water deficit. THE PLANT GENOME 2022; 15:e20199. [PMID: 35322562 DOI: 10.1002/tpg2.20199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Tall fescue (Festuca arundinacea Schreb.) is a popular pasture and turf grass particularly known for drought resistance, allowing for its persistence in locations that are unfavorable for other cool-season grasses. Also, its seed-borne fungal symbiont (endophyte) Epichloë coenophiala, which resides in the crown and pseudostem, can be a contributing factor in its drought tolerance. Because it contains the apical meristems, crown survival under drought stress is critical to plant survival as well as the endophyte. In this study, we subjected tall fescue plants with their endophyte to water-deficit stress or, as controls with normal watering, then compared plant transcriptome responses in four vegetative tissues: leaf blades, pseudostem, crown, and roots. A transcript was designated a differentially expressed gene (DEG) if it exhibited at least a twofold expression difference between stress and control samples with an adjusted p value of .001. Pathway analysis of the DEGs across all tissue types included photosynthesis, carbohydrate metabolism, phytohormone biosynthesis and signaling, cellular organization, and a transcriptional regulation. While no specific pathway was observed to be differentially expressed in the crown, genes encoding auxin response factors, nuclear pore anchors, structural maintenance of chromosomes, and class XI myosin proteins were more highly differentially expressed in crown than in the other vegetative tissues, suggesting that regulation in expression of these genes in the crown may aid in survival of the meristems in the crown.
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Affiliation(s)
- Manohar Chakrabarti
- Dep. of Plant and Soil Sciences, Univ. of Kentucky, Lexington, KY, 40546-0312, USA
| | - Padmaja Nagabhyru
- Dep. of Plant Pathology, Univ. of Kentucky, Lexington, KY, 40546-0312, USA
| | | | - Randy D Dinkins
- USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY, 40546-0091, USA
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17
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Vertically Transmitted Epichloë Systemic Endophyte Enhances Drought Tolerance of Achnatherum inebrians Host Plants through Promoting Photosynthesis and Biomass Accumulation. J Fungi (Basel) 2022; 8:jof8050512. [PMID: 35628767 PMCID: PMC9144827 DOI: 10.3390/jof8050512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/16/2022] Open
Abstract
Achnatherum inebrians (drunken horse grass, DHG) plants, a dominant grass species in the arid and semi-arid regions of northwest China, symbiotic with an Epichloë fungal endophyte, is well adapted to drought. However, little is known about how the presence of the foliar Epichloë endophyte enhances the tolerance of DHG to drought at the molecular level. This study explored the positive effects of the presence of the Epichloë endophyte on plant growth, biomass, and photosynthetic efficiency and processes of DHG under non-drought and two drought (moderate and severe) treatments, using RNA sequencing to compare transcriptomes. The transcriptome results showed that 32 selected unigenes involved in the photosynthesis processes within Epichloë symbiotic plants were differently expressed (DEGs) versus non-symbiotic plants. The majority of these selected DEGs were upregulated in Epichloë symbiotic plants versus non-symbiotic plants, such as upregulated unigenes (c51525.graph_c1, c47798.graph_c0 & c64087.graph_c0) under drought conditions. In line with the transcriptomes data, the presence of the Epichloë endophyte promoted the photosynthetic rate and biomass accumulation of DHG plants, and the relationship between the photosynthetic rate and biomass is linear and significant. The presence of the endophyte only increased the biomass per tiller of DHG plants under drought. This study provides further insights into the molecular mechanisms that underlie the enhanced plant growth and drought tolerance of Epichloë-symbiotic DHG plants.
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18
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Cheng C, Wang J, Hou W, Malik K, Zhao C, Niu X, Liu Y, Huang R, Li C, Nan Z. Elucidating the Molecular Mechanisms by which Seed-Borne Endophytic Fungi, Epichloë gansuensis, Increases the Tolerance of Achnatherum inebrians to NaCl Stress. Int J Mol Sci 2021; 22:ijms222413191. [PMID: 34947985 PMCID: PMC8706252 DOI: 10.3390/ijms222413191] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/21/2021] [Accepted: 11/29/2021] [Indexed: 12/29/2022] Open
Abstract
Seed-borne endophyte Epichloë gansuensis enhance NaCl tolerance in Achnatherum inebrians and increase its biomass. However, the molecular mechanism by which E. gansuensis increases the tolerance of host grasses to NaCl stress is unclear. Hence, we firstly explored the full-length transcriptome information of A. inebrians by PacBio RS II. In this work, we obtained 738,588 full-length non-chimeric reads, 36,105 transcript sequences and 27,202 complete CDSs from A. inebrians. We identified 3558 transcription factors (TFs), 15,945 simple sequence repeats and 963 long non-coding RNAs of A. inebrians. The present results show that 2464 and 1817 genes were differentially expressed by E. gansuensis in the leaves of E+ and E− plants at 0 mM and 200 mM NaCl concentrations, respectively. In addition, NaCl stress significantly regulated 4919 DEGs and 502 DEGs in the leaves of E+ and E− plants, respectively. Transcripts associated with photosynthesis, plant hormone signal transduction, amino acids metabolism, flavonoid biosynthetic process and WRKY TFs were differentially expressed by E. gansuensis; importantly, E. gansuensis up-regulated biology processes (brassinosteroid biosynthesis, oxidation–reduction, cellular calcium ion homeostasis, carotene biosynthesis, positive regulation of proteasomal ubiquitin-dependent protein catabolism and proanthocyanidin biosynthesis) of host grass under NaCl stress, which indicated an increase in the ability of host grasses’ adaptation to NaCl stress. In conclusion, our study demonstrates the molecular mechanism for E. gansuensis to increase the tolerance to salt stress in the host, which provides a theoretical basis for the molecular breed to create salt-tolerant forage with endophytes.
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Affiliation(s)
- Chen Cheng
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
| | - Jianfeng Wang
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China;
- Collaborative Innovation Center for Western Ecological Safety, Lanzhou University, Lanzhou 730000, China
- Correspondence:
| | - Wenpeng Hou
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
| | - Kamran Malik
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China;
| | - Chengzhou Zhao
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China;
- Tibetan Medicine Research Center, College of Tibetan Medicine, Qinghai University, Xining 810016, China
| | - Xueli Niu
- School of Life Science and Technology, Lingnan Normal University, Zhanjiang 524048, China;
| | - Yinglong Liu
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
| | - Rong Huang
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
| | - Chunjie Li
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
| | - Zhibiao Nan
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China; (C.C.); (W.H.); (Y.L.); (R.H.); (C.L.); (Z.N.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China;
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19
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Harrison JG, Beltran LP, Buerkle CA, Cook D, Gardner DR, Parchman TL, Poulson SR, Forister ML. A suite of rare microbes interacts with a dominant, heritable, fungal endophyte to influence plant trait expression. THE ISME JOURNAL 2021; 15:2763-2778. [PMID: 33790425 PMCID: PMC8397751 DOI: 10.1038/s41396-021-00964-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 02/08/2021] [Accepted: 03/15/2021] [Indexed: 01/31/2023]
Abstract
Endophytes are microbes that live, for at least a portion of their life history, within plant tissues. Endophyte assemblages are often composed of a few abundant taxa and many infrequently observed, low-biomass taxa that are, in a word, rare. The ways in which most endophytes affect host phenotype are unknown; however, certain dominant endophytes can influence plants in ecologically meaningful ways-including by affecting growth and immune system functioning. In contrast, the effects of rare endophytes on their hosts have been unexplored, including how rare endophytes might interact with abundant endophytes to shape plant phenotype. Here, we manipulate both the suite of rare foliar endophytes (including both fungi and bacteria) and Alternaria fulva-a vertically transmitted and usually abundant fungus-within the fabaceous forb Astragalus lentiginosus. We report that rare, low-biomass endophytes affected host size and foliar %N, but only when the heritable fungal endophyte (A. fulva) was not present. A. fulva also reduced plant size and %N, but these deleterious effects on the host could be offset by a negative association we observed between this heritable fungus and a foliar pathogen. These results demonstrate how interactions among endophytic taxa determine the net effects on host plants and suggest that the myriad rare endophytes within plant leaves may be more than a collection of uninfluential, commensal organisms, but instead have meaningful ecological roles.
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Affiliation(s)
- Joshua G. Harrison
- grid.135963.b0000 0001 2109 0381Department of Botany, University of Wyoming, Laramie, WY USA
| | - Lyra P. Beltran
- grid.266818.30000 0004 1936 914XEcology, Evolution, and Conservation Biology Program, Biology Department, University of Nevada, Reno, NV USA
| | - C. Alex Buerkle
- grid.135963.b0000 0001 2109 0381Department of Botany, University of Wyoming, Laramie, WY USA
| | - Daniel Cook
- grid.417548.b0000 0004 0478 6311Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Logan, UT USA
| | - Dale R. Gardner
- grid.417548.b0000 0004 0478 6311Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Logan, UT USA
| | - Thomas L. Parchman
- grid.266818.30000 0004 1936 914XEcology, Evolution, and Conservation Biology Program, Biology Department, University of Nevada, Reno, NV USA
| | - Simon R. Poulson
- grid.266818.30000 0004 1936 914XDepartment of Geological Sciences & Engineering, University of Nevada, Reno, NV USA
| | - Matthew L. Forister
- grid.266818.30000 0004 1936 914XEcology, Evolution, and Conservation Biology Program, Biology Department, University of Nevada, Reno, NV USA
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20
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Wu B, Cox MP. Comparative genomics reveals a core gene toolbox for lifestyle transitions in Hypocreales fungi. Environ Microbiol 2021; 23:3251-3264. [PMID: 33939870 PMCID: PMC8360070 DOI: 10.1111/1462-2920.15554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/13/2022]
Abstract
Fungi have evolved diverse lifestyles and adopted pivotal new roles in both natural ecosystems and human environments. However, the molecular mechanisms underlying their adaptation to new lifestyles are obscure. Here, we hypothesize that genes shared across all species with the same lifestyle, but absent in genera with alternative lifestyles, are crucial to that lifestyle. By analysing dozens of species within four genera in a fungal order, with each genus following a different lifestyle, we find that genus-specific genes are typically few in number. Notably, not all genus-specific genes appear to derive from de novo birth, with most instead reflecting recurrent loss across the fungi. Importantly, however, a subset of these genus-specific genes are shared by fungi with the same lifestyle in quite different evolutionary orders, thus supporting the view that some genus-specific genes are necessary for specific lifestyles. These lifestyle-specific genes are enriched for key functional classes and often exhibit specialized expression patterns. Genus-specific selection also contributes to lifestyle transitions, and is especially associated with intensity of pathogenesis. Our study, therefore, suggests that fungal adaptation to new lifestyles often requires just a small number of core genes, with gene turnover and positive selection playing complementary roles.
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Affiliation(s)
- Baojun Wu
- Statistics and Bioinformatics Group, School of Fundamental SciencesMassey UniversityPalmerston North4410New Zealand
- Bio‐Protection Research CentreMassey UniversityPalmerston North4410New Zealand
| | - Murray P. Cox
- Statistics and Bioinformatics Group, School of Fundamental SciencesMassey UniversityPalmerston North4410New Zealand
- Bio‐Protection Research CentreMassey UniversityPalmerston North4410New Zealand
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21
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Bastías DA, Gianoli E, Gundel PE. Fungal endophytes can eliminate the plant growth-defence trade-off. THE NEW PHYTOLOGIST 2021; 230:2105-2113. [PMID: 33690884 DOI: 10.1111/nph.17335] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/08/2021] [Indexed: 05/27/2023]
Abstract
A trade-off between growth and defence functions is commonly observed in plants. We propose that the association of plants with Epichloë fungal endophytes may eliminate this trade-off. This would be a consequence of the double role of these endophytes in host plants: the stimulation of plant growth hormones (e.g. gibberellins) and the fungal production of antiherbivore alkaloids. We put forward a model that integrates this dual effect of endophytes on plant growth and defence and test its predictions by means of meta-analysis of published literature. Our results support the notion that the enhanced plant resistance promoted by endophytes does not compromise plant growth. The limits and ecological benefits of this endophyte-mediated lack of plant growth-defence trade-off are discussed.
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Affiliation(s)
- Daniel A Bastías
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Ernesto Gianoli
- Departamento de Biología, Universidad de La Serena, Casilla 554, La Serena, Chile
- Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Pedro E Gundel
- Facultad de Agronomía, IFEVA, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Laboratorio de Biología Vegetal, Instituto de Ciencias Biológicas, Universidad de Talca, Campus Lircay, Talca, Chile
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22
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Whole-Genome Sequencing and Annotation of 10 Endophytic and Epiphytic Bacteria Isolated from Lolium arundinaceum. Microbiol Resour Announc 2021; 10:10/19/e00317-21. [PMID: 33986094 PMCID: PMC8142580 DOI: 10.1128/mra.00317-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We report the whole-genome sequence and annotation of 10 endophytic and epiphytic bacteria isolated from the grass Lolium arundinaceum as part of a laboratory exercise in a Fundamentals of Plant Biochemistry and Pathology undergraduate course (BIOL403) at the Rochester Institute of Technology in Rochester, New York. We report the whole-genome sequence and annotation of 10 endophytic and epiphytic bacteria isolated from the grass Lolium arundinaceum as part of a laboratory exercise in a Fundamentals of Plant Biochemistry and Pathology undergraduate course (BIOL403) at the Rochester Institute of Technology in Rochester, New York.
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Hettiarachchige IK, Vander Jagt CJ, Mann RC, Sawbridge TI, Spangenberg GC, Guthridge KM. Global Changes in Asexual Epichloë Transcriptomes during the Early Stages, from Seed to Seedling, of Symbiotum Establishment. Microorganisms 2021; 9:microorganisms9050991. [PMID: 34064362 PMCID: PMC8147782 DOI: 10.3390/microorganisms9050991] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/30/2021] [Accepted: 04/30/2021] [Indexed: 11/16/2022] Open
Abstract
Asexual Epichloë fungi are strictly seed-transmitted endophytic symbionts of cool-season grasses and spend their entire life cycle within the host plant. Endophyte infection can confer protective benefits to its host through the production of bioprotective compounds. Inversely, plants provide nourishment and shelter to the resident endophyte in return. Current understanding of the changes in global gene expression of asexual Epichloë endophytes during the early stages of host-endophyte symbiotum is limited. A time-course study using a deep RNA-sequencing approach was performed at six stages of germination, using seeds infected with one of three endophyte strains belonging to different representative taxa. Analysis of the most abundantly expressed endophyte genes identified that most were predicted to have a role in stress and defence responses. The number of differentially expressed genes observed at early time points was greater than those detected at later time points, suggesting an active transcriptional reprogramming of endophytes at the onset of seed germination. Gene ontology enrichment analysis revealed dynamic changes in global gene expression consistent with the developmental processes of symbiotic relationships. Expression of pathway genes for biosynthesis of key secondary metabolites was studied comprehensively and fuzzy clustering identified some unique expression patterns. Furthermore, comparisons of the transcriptomes from three endophyte strains in planta identified genes unique to each strain, including genes predicted to be associated with secondary metabolism. Findings from this study highlight the importance of better understanding the unique properties of individual endophyte strains and will serve as an excellent resource for future studies of host-endophyte interactions.
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Affiliation(s)
- Inoka K. Hettiarachchige
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
| | - Christy J. Vander Jagt
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
| | - Ross C. Mann
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
| | - Timothy I. Sawbridge
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC 3086, Australia
| | - German C. Spangenberg
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC 3086, Australia
| | - Kathryn M. Guthridge
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC 3083, Australia; (I.K.H.); (C.J.V.J.); (R.C.M.); (T.I.S.); (G.C.S.)
- Correspondence:
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Chen XL, Sun MC, Chong SL, Si JP, Wu LS. Transcriptomic and Metabolomic Approaches Deepen Our Knowledge of Plant-Endophyte Interactions. FRONTIERS IN PLANT SCIENCE 2021; 12:700200. [PMID: 35154169 PMCID: PMC8828500 DOI: 10.3389/fpls.2021.700200] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 12/22/2021] [Indexed: 05/10/2023]
Abstract
In natural systems, plant-symbiont-pathogen interactions play important roles in mitigating abiotic and biotic stresses in plants. Symbionts have their own special recognition ways, but they may share some similar characteristics with pathogens based on studies of model microbes and plants. Multi-omics technologies could be applied to study plant-microbe interactions, especially plant-endophyte interactions. Endophytes are naturally occurring microbes that inhabit plants, but do not cause apparent symptoms in them, and arise as an advantageous source of novel metabolites, agriculturally important promoters, and stress resisters in their host plants. Although biochemical, physiological, and molecular investigations have demonstrated that endophytes confer benefits to their hosts, especially in terms of promoting plant growth, increasing metabolic capabilities, and enhancing stress resistance, plant-endophyte interactions consist of complex mechanisms between the two symbionts. Further knowledge of these mechanisms may be gained by adopting a multi-omics approach. The involved interaction, which can range from colonization to protection against adverse conditions, has been investigated by transcriptomics and metabolomics. This review aims to provide effective means and ways of applying multi-omics studies to solve the current problems in the characterization of plant-microbe interactions, involving recognition and colonization. The obtained results should be useful for identifying the key determinants in such interactions and would also provide a timely theoretical and material basis for the study of interaction mechanisms and their applications.
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Talukder SK, Islam MS, Krom N, Chang J, Saha MC. Drought Responsive Putative Marker-Trait Association in Tall Fescue as Influenced by the Presence of a Novel Endophyte. FRONTIERS IN PLANT SCIENCE 2021; 12:729797. [PMID: 34745162 PMCID: PMC8565914 DOI: 10.3389/fpls.2021.729797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/22/2021] [Indexed: 05/04/2023]
Abstract
Tall fescue (Festuca arundinacea Schreb.) is one of the most important cool-season perennial obligatory outcrossing forage grasses in the United States. The production and persistence of tall fescue is significantly affected by drought in the south-central United States. Shoot-specific endophyte (Epichloë coenophiala)-infected tall fescue showed superior performance under both biotic and abiotic stress conditions. We performed a genome-wide association analysis using clonal pairs of novel endophyte AR584-positive (EP) and endophyte-free (EF) tall fescue populations consisting of 205 genotypes to identify marker-trait associations (MTAs) that contribute to drought tolerance. The experiment was performed through November 2014 to June 2018 in the field, and phenotypic data were taken on plant height, plant spread, plant vigor, and dry biomass weight under natural summer conditions of sporadic drought. Genotyping-by-sequencing of the population generated 3,597 high quality single nucleotide polymorphisms (SNPs) for further analysis. We identified 26 putative drought responsive MTAs (17 specific to EP, eight specific to EF, and one in both EP and EF populations) and nine of them (i.e., V.ep_10, S.ef_12, V.ep_27, HSV.ef_31, S.ep_30, SV.ef_32, V.ep_68, V.ef_56, and H.ef_57) were identified within 0.5 Mb region in the tall fescue genome (44.5-44.7, 75.3-75.8, 77.5-77.9 and 143.7-144.2 Mb). Using 26 MTAs, 11 tall fescue genotypes were selected for subsequent study to develop EP and EF drought tolerant tall fescue populations. Ten orthologous genes (six for EP and four for EF population) were identified in Brachypodium genome as potential candidates for drought tolerance in tall fescue, which were also earlier reported for their involvement in abiotic stress tolerance. The MTAs and candidate genes identified in this study will be useful for marker-assisted selection in improving drought tolerance of tall fescue as well opening avenue for further drought study in tall fescue.
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Affiliation(s)
- Shyamal K. Talukder
- Grass Genomics, Noble Research Institute LLC, Ardmore, OK, United States
- Texas A&M AgriLife Research Center, Beaumont, TX, United States
| | - Md. Shofiqul Islam
- Grass Genomics, Noble Research Institute LLC, Ardmore, OK, United States
| | - Nick Krom
- Scientific Computing, Noble Research Institute LLC, Ardmore, OK, United States
| | - Junil Chang
- Scientific Computing, Noble Research Institute LLC, Ardmore, OK, United States
| | - Malay C. Saha
- Grass Genomics, Noble Research Institute LLC, Ardmore, OK, United States
- *Correspondence: Malay C. Saha,
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26
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Caradus JR, Johnson LJ. Epichloë Fungal Endophytes-From a Biological Curiosity in Wild Grasses to an Essential Component of Resilient High Performing Ryegrass and Fescue Pastures. J Fungi (Basel) 2020; 6:E322. [PMID: 33261217 PMCID: PMC7720123 DOI: 10.3390/jof6040322] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/13/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
The relationship between Epichloë endophytes found in a wide range of temperate grasses spans the continuum from antagonistic to mutualistic. The diversity of asexual mutualistic types can be characterised by the types of alkaloids they produce in planta. Some of these are responsible for detrimental health and welfare issues of ruminants when consumed, while others protect the host plant from insect pests and pathogens. In many temperate regions they are an essential component of high producing resilient tall fescue and ryegrass swards. This obligate mutualism between fungus and host is a seed-borne technology that has resulted in several commercial products being used with high uptake rates by end-user farmers, particularly in New Zealand and to a lesser extent Australia and USA. However, this has not happened by chance. It has been reliant on multi-disciplinary research teams undertaking excellent science to understand the taxonomic relationships of these endophytes, their life cycle, symbiosis regulation at both the cellular and molecular level, and the impact of secondary metabolites, including an understanding of their mammalian toxicity and bioactivity against insects and pathogens. Additionally, agronomic trials and seed biology studies of these microbes have all contributed to the delivery of robust and efficacious products. The supply chain from science, through seed companies and retailers to the end-user farmer needs to be well resourced providing convincing information on the efficacy and ensuring effective quality control to result in a strong uptake of these Epichloë endophyte technologies in pastoral agriculture.
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Affiliation(s)
- John R. Caradus
- Grasslanz Technology Ltd., Palmerston North PB11008, New Zealand
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Wang J, Hou W, Christensen MJ, Li X, Xia C, Li C, Nan Z. Role of Epichloë Endophytes in Improving Host Grass Resistance Ability and Soil Properties. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:6944-6955. [PMID: 32551564 DOI: 10.1021/acs.jafc.0c01396] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The past decade has witnessed significant advances in understanding the interaction between grasses and systemic fungal endophytes of the genus Epichloë, with evidence that plants have evolved multiple strategies to cope with abiotic stresses by reprogramming physiological responses. Soil nutrients directly affect plant growth, while soil microbes are also closely connected to plant growth and health. Epichloë endophytes could affect soil fertility by modifying soil nutrient contents and soil microbial diversity. Therefore, we analyze recent advances in our understanding of the role of Epichloë endophytes under the various abiotic stresses and the role of grass-Epichloë symbiosis on soil fertility. Various cool-season grasses are infected by Epichloë species, which contribute to health, growth, persistence, and seed survival of host grasses by regulating key systems, including photosynthesis, osmotic regulation, and antioxidants and activity of key enzymes of host physiology processes under abiotic stresses. The Epichloë endophyte offers significant prospects to magnify the crop yield, plant resistance, and food safety in ecological systems by modulating soil physiochemical properties and soil microbes. The enhancing resistance of host grasses to abiotic stresses by an Epichloë endophyte is a complex manifestation of different physiological and biochemical events through regulating soil properties and soil microbes by the fungal endophyte. The Epichloë-mediated mechanisms underlying regulation of abiotic stress responses are involved in osmotic adjustment, antioxidant machinery, photosynthetic system, and activity of key enzymes critical in developing plant adaptation strategies to abiotic stress. Therefore, the Epichloë endophytes are an attractive choice in increasing resistance of plants to abiotic stresses and are also a good candidate for improving soil fertility and regulating microbial diversity to improve plant growth.
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Affiliation(s)
- Jianfeng Wang
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
| | - Wenpeng Hou
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
| | - Michael J Christensen
- Grasslands Research Centre, AgResearch, Private Bag 11-008, Palmerston North 4442, New Zealand
| | - Xiuzhang Li
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai Academy of Animal and Veterinary Sciences, Qinghai University, Xining, Qinghai 810016, People's Republic of China
| | - Chao Xia
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
| | - Chunjie Li
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
| | - Zhibiao Nan
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
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28
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Green KA, Berry D, Feussner K, Eaton CJ, Ram A, Mesarich CH, Solomon P, Feussner I, Scott B. Lolium perenne apoplast metabolomics for identification of novel metabolites produced by the symbiotic fungus Epichloë festucae. THE NEW PHYTOLOGIST 2020; 227:559-571. [PMID: 32155669 PMCID: PMC7317419 DOI: 10.1111/nph.16528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 02/28/2020] [Indexed: 05/05/2023]
Abstract
Epichloë festucae is an endophytic fungus that forms a symbiotic association with Lolium perenne. Here we analysed how the metabolome of the ryegrass apoplast changed upon infection of this host with sexual and asexual isolates of E. festucae. A metabolite fingerprinting approach was used to analyse the metabolite composition of apoplastic wash fluid from uninfected and infected L. perenne. Metabolites enriched or depleted in one or both of these treatments were identified using a set of interactive tools. A genetic approach in combination with tandem MS was used to identify a novel product of a secondary metabolite gene cluster. Metabolites likely to be present in the apoplast were identified using MarVis in combination with the BioCyc and KEGG databases, and an in-house Epichloë metabolite database. We were able to identify the known endophyte-specific metabolites, peramine and epichloëcyclins, as well as a large number of unknown markers. To determine whether these methods can be applied to the identification of novel Epichloë-derived metabolites, we deleted a gene encoding a NRPS (lgsA) that is highly expressed in planta. Comparative MS analysis of apoplastic wash fluid from wild-type- vs mutant-infected plants identified a novel Leu/Ile glycoside metabolite present in the former.
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Affiliation(s)
- Kimberly A. Green
- School of Fundamental SciencesMassey UniversityPalmerston North4442New Zealand
- Bioprotection Research CentreMassey UniversityPalmerston North4442New Zealand
| | - Daniel Berry
- School of Fundamental SciencesMassey UniversityPalmerston North4442New Zealand
- Bioprotection Research CentreMassey UniversityPalmerston North4442New Zealand
| | - Kirstin Feussner
- Department of Plant BiochemistryAlbrecht von Haller Institute for Plant SciencesUniversity of GoettingenD‐37077GoettingenGermany
- Service Unit for Metabolomics and LipidomicsGoettingen Center for Molecular Biosciences (GZMB)University of GoettingenD‐37077GoettingenGermany
| | - Carla J. Eaton
- School of Fundamental SciencesMassey UniversityPalmerston North4442New Zealand
- Bioprotection Research CentreMassey UniversityPalmerston North4442New Zealand
| | - Arvina Ram
- School of Fundamental SciencesMassey UniversityPalmerston North4442New Zealand
| | - Carl H. Mesarich
- Bioprotection Research CentreMassey UniversityPalmerston North4442New Zealand
- School of Agriculture and EnvironmentMassey UniversityPalmerston North4442New Zealand
| | - Peter Solomon
- Research School of BiologyAustralian National UniversityCanberraACT0200Australia
| | - Ivo Feussner
- Department of Plant BiochemistryAlbrecht von Haller Institute for Plant SciencesUniversity of GoettingenD‐37077GoettingenGermany
- Service Unit for Metabolomics and LipidomicsGoettingen Center for Molecular Biosciences (GZMB)University of GoettingenD‐37077GoettingenGermany
- Department of Plant BiochemistryGoettingen Center for Molecular Biosciences (GZMB)University of GoettingenD‐37077GoettingenGermany
| | - Barry Scott
- School of Fundamental SciencesMassey UniversityPalmerston North4442New Zealand
- Bioprotection Research CentreMassey UniversityPalmerston North4442New Zealand
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Cao Z, Kapoor K, Li L, Banniza S. Interactive Gene Expression Patterns of Susceptible and Resistant Lens ervoides Recombinant Inbred Lines and the Necrotroph Ascochyta lentis. Front Microbiol 2020; 11:1259. [PMID: 32670221 PMCID: PMC7326948 DOI: 10.3389/fmicb.2020.01259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/18/2020] [Indexed: 11/13/2022] Open
Abstract
Ascochyta lentis is a foliar pathogen of Lens species and is of worldwide importance in cultivated lentil production. High levels of resistance were identified in the wild species Lens ervoides. This resistance was explored through histopathology, qPCR estimation of fungal biomass and transcriptome sequencing in a susceptible and a resistant recombinant inbred line (RIL) of L. ervoides infected with an aggressive isolate of A. lentis. Necrotrophic growth was delayed in the resistant RIL compared to accelerated necrotrophy of A. lentis in the susceptible RIL. Analysis of the fungal secretome indicated that the early activation of cell wall-degrading enzymes contributed to increased virulence of A. lentis. On the host side, gene co-expression analysis revealed that the invasion by A. lentis caused mRNA, DNA and protein decay in infected plants regardless of the level of resistance in the host. The resistant RIL exhibited a stronger gene co-expression in lipid localization and sulfur processes, and cellular responses to nutrients and stimuli than the susceptible RIL. In addition, differential gene analysis revealed that the repression of both, gibberellin signaling and cell death associated with the hypersensitive response (HR), were associated with enhanced A. lentis resistance.
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Affiliation(s)
- Zhe Cao
- Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Karan Kapoor
- Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Li Li
- Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Sabine Banniza
- Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK, Canada
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30
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Bharadwaj R, Jagadeesan H, Kumar SR, Ramalingam S. Molecular mechanisms in grass-Epichloë interactions: towards endophyte driven farming to improve plant fitness and immunity. World J Microbiol Biotechnol 2020; 36:92. [PMID: 32562008 DOI: 10.1007/s11274-020-02868-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/10/2020] [Indexed: 11/26/2022]
Abstract
All plants harbor many microbial species including bacteria and fungi in their tissues. The interactions between the plant and these microbes could be symbiotic, mutualistic, parasitic or commensalistic. Mutualistic microorganisms are endophytic in nature and are known to play a role in plant growth, development and fitness. Endophytes display complex diversity depending upon the agro-climatic conditions and this diversity could be exploited for crop improvement and sustainable agriculture. Plant-endophyte partnerships are highly specific, several genetic and molecular cascades play a key role in colonization of endophytes in host plants leading to rapid changes in host and endophyte metabolism. This results in the accumulation of secondary metabolites, which play an important role in plant defense against biotic and abiotic stress conditions. Alkaloids are one of the important class of metabolites produced by Epichloë genus and other related classes of endophytes and confer protection against insect and mammalian herbivory. In this context, this review discusses the evolutionary aspects of the Epichloë genus along with key molecular mechanisms determining the lifestyle of Epichloë endophytes in host system. Novel hypothesis is proposed to outline the initial cellular signaling events during colonization of Epichloë in cool season grasses. Complex clustering of alkaloid biosynthetic genes and molecular mechanisms involved in the production of alkaloids have been elaborated in detail. The natural defense and advantages of the endophyte derived metabolites have also been extensively discussed. Finally, this review highlights the importance of endophyte-arbitrated plant immunity to develop novel approaches for eco-friendly agriculture.
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Affiliation(s)
- R Bharadwaj
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - H Jagadeesan
- Department of Biotechnology, PSG College of Technology, Coimbatore, Tamil Nadu, India
| | - S R Kumar
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - S Ramalingam
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
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Wang J, Hou W, Christensen MJ, Xia C, Chen T, Zhang Z, Nan Z. The fungal endophyte Epichloë gansuensis increases NaCl-tolerance in Achnatherum inebrians through enhancing the activity of plasma membrane H +-ATPase and glucose-6-phosphate dehydrogenase. SCIENCE CHINA-LIFE SCIENCES 2020; 64:452-465. [PMID: 32430851 DOI: 10.1007/s11427-020-1674-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/08/2020] [Indexed: 12/13/2022]
Abstract
Salt stress negatively affects plant growth, and the fungal endophyte Epichloëgansuensis increases the tolerance of its host grass species, Achnatherum inebrians, to abiotic stresses. In this work, we first evaluated the effects of E. gansuensis on glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) H+-ATPase activity of Achnatherum inebrians plants under varying NaCl concentrations. Our results showed that the presence of E. gansuensis increased G6PDH, PM H+-ATPase, superoxide dismutase and catalase activity to decrease O2•-, H2O2 and Na+ contents in A. inebrians under NaCl stress, resulting in enhanced salt tolerance. In addition, the PM NADPH oxidase activity and NADPH/NADP+ ratios were all lower in A. inebrians with E. ganusensis plants than A. inebrians plants without this endophyte under NaCl stress. In conclusion, E. gansuensis has a positive role in improving host grass yield under NaCl stress by enhancing the activity of G6PDH and PM H+-ATPase to decrease ROS content. This provides a new way for the selection of stress-resistant and high-quality forage varieties by the use of systemic fungal endophytes.
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Affiliation(s)
- Jianfeng Wang
- State Key Laboratory of Grassland Agro-ecosystems; Center for Grassland Microbiome; Key Laboratory of Grassland Livestock Industry Innovation; Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry; Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Wenpeng Hou
- State Key Laboratory of Grassland Agro-ecosystems; Center for Grassland Microbiome; Key Laboratory of Grassland Livestock Industry Innovation; Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry; Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Michael J Christensen
- Retired scientist of AgResearch, Grasslands Research Centre, Private Bag 11-008, Palmerston North, 4442, New Zealand
| | - Chao Xia
- State Key Laboratory of Grassland Agro-ecosystems; Center for Grassland Microbiome; Key Laboratory of Grassland Livestock Industry Innovation; Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry; Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Tao Chen
- State Key Laboratory of Grassland Agro-ecosystems; Center for Grassland Microbiome; Key Laboratory of Grassland Livestock Industry Innovation; Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry; Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Zhixin Zhang
- College of Grassland Agriculture, Northwest A&F University, Yangling, 712100, China
| | - Zhibiao Nan
- State Key Laboratory of Grassland Agro-ecosystems; Center for Grassland Microbiome; Key Laboratory of Grassland Livestock Industry Innovation; Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry; Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China.
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32
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Forte FP, Schmid J, Dijkwel PP, Nagy I, Hume DE, Johnson RD, Simpson WR, Monk SM, Zhang N, Sehrish T, Asp T. Fungal Endophyte Colonization Patterns Alter Over Time in the Novel Association Between Lolium perenne and Epichloë Endophyte AR37. FRONTIERS IN PLANT SCIENCE 2020; 11:570026. [PMID: 33193501 PMCID: PMC7658011 DOI: 10.3389/fpls.2020.570026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/22/2020] [Indexed: 05/16/2023]
Abstract
Infection of the pasture grass Lolium perenne with the seed-transmitted fungal endophyte Epichloë festucae enhances its resilience to biotic and abiotic stress. Agricultural benefits of endophyte infection can be increased by generating novel symbiotic associations through inoculating L. perenne with selected Epichloë strains. Natural symbioses have coevolved over long periods. Thus, artificial symbioses will probably not have static properties, but symbionts will coadapt over time improving the fitness of the association. Here we report for the first time on temporal changes in a novel association of Epichloë strain AR37 and the L. perenne cultivar Grasslands Samson. Over nine generations, a seed maintenance program had increased the endophyte seed transmission rates to > 95% (from an initial 76%). We observed an approximately fivefold decline in endophyte biomass concentration in vegetative tissues over time (between generations 2 and 9). This indicates strong selection pressure toward reducing endophyte-related fitness costs by reducing endophyte biomass, without compromising the frequency of endophyte transmission to seed. We observed no obvious changes in tillering and only minor transcriptomic changes in infected plants over time. Functional analysis of 40 plant genes, showing continuously decreasing expression over time, suggests that adaptation of host metabolism and defense mechanisms are important for increasing the fitness of this association, and possibly fitness of such symbioses in general. Our results indicate that fitness of novel associations is likely to improve over time and that monitoring changes in novel associations can assist in identifying key features of endophyte-mediated enhancement of host fitness.
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Affiliation(s)
- Flavia Pilar Forte
- Center for Quantitative Genetics and Genomics, Aarhus University, Slagelse, Denmark
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- *Correspondence: Flavia Pilar Forte,
| | - Jan Schmid
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- Ferguson Street Laboratories, Palmerston North, New Zealand
| | - Paul P. Dijkwel
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Istvan Nagy
- Center for Quantitative Genetics and Genomics, Aarhus University, Slagelse, Denmark
| | - David E. Hume
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Wayne R. Simpson
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Ningxin Zhang
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Tina Sehrish
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Torben Asp
- Center for Quantitative Genetics and Genomics, Aarhus University, Slagelse, Denmark
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33
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Wang R, Clarke BB, Belanger FC. Transcriptome Analysis of Choke Stroma and Asymptomatic Inflorescence Tissues Reveals Changes in Gene Expression in Both Epichloë festucae and Its Host Plant Festuca rubra subsp. rubra. Microorganisms 2019; 7:E567. [PMID: 31744076 PMCID: PMC6921078 DOI: 10.3390/microorganisms7110567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 02/07/2023] Open
Abstract
Many cool-season grasses have symbiotic relationships with Epichloë (Ascomycota, Clavicipitaceae) fungal endophytes that inhabit the intercellular spaces of the above-ground parts of the host plants. The presence of the Epichloë endophytes is generally beneficial to the hosts due to enhanced tolerance to biotic and abiotic stresses conferred by the endophytes. Many Epichloë spp. are asexual, and those infections always remain asymptomatic. However, some Epichloë spp. have a sexual stage and produce a macroscopic fruiting body, a stroma, that envelops the developing inflorescence causing a syndrome termed "choke disease". Here, we report a fungal and plant gene expression analysis of choke stroma tissue and asymptomatic inflorescence tissue of Epichloë festucae-infected strong creeping red fescue (Festuca rubra subsp. rubra). Hundreds of fungal genes and over 10% of the plant genes were differentially expressed when comparing the two tissue types. The differentially expressed fungal genes in the choke stroma tissue indicated a change in carbohydrate and lipid metabolism, as well as a change in expression of numerous genes for candidate effector proteins. Plant stress-related genes were up-regulated in the stroma tissue, suggesting the plant host was responding to the epiphytic stage of E. festucae as a pathogen.
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Affiliation(s)
| | | | - Faith C. Belanger
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (B.B.C.)
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34
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Dinkins RD, Nagabhyru P, Young CA, West CP, Schardl CL. Transcriptome Analysis and Differential Expression in Tall Fescue Harboring Different Endophyte Strains in Response to Water Deficit. THE PLANT GENOME 2019; 12:180071. [PMID: 31290925 DOI: 10.3835/plantgenome2018.09.0071] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.) Dumort. = Festuca arundinacea var. arundinacea Schreb.] plant genotypes with an Epichloë coenophiala (Morgan-Jones & W. Gams) C.W. Bacon & Schardl common toxic endophyte (CTE), one with a nontoxic strain (NTE19) and one with another Epichloë species (FaTG-4) were evaluated and compared with their respective endophyte-free clones for responses to water-deficit stress in the greenhouse. One of the plant genotypes (P27) showed a positive effect of its CTE strain on tiller production after stress and resumed watering. In transcriptome analysis of the pseudostems (leaf sheath whorls), differentially expressed genes (DEGs) were defined as having at least twofold expression difference and false discovery rate (FDR) < 0.05 in comparisons of water treatment (stressed or watered), endophyte presence or absence, or both. Stress affected 38% of the plant transcripts including those for the expected stress-response pathways. The DEGs affected by endophyte in stressed plants were unique to individual plant genotypes. In unstressed plants, endophyte presence tended to reduce expression of genes putatively for defense against fungi, but in unstressed P27 endophyte presence there was enhanced expression of dehydrin and heat shock protein genes. Our results indicated subtle and variable effects of endophytes on tall fescue gene expression; where the endophyte confers protection, its effects on plant gene expression may help prime the plant for stress resistance.
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35
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Yuan J, Zhang W, Sun K, Tang MJ, Chen PX, Li X, Dai CC. Comparative Transcriptomics and Proteomics of Atractylodes lancea in Response to Endophytic Fungus Gilmaniella sp. AL12 Reveals Regulation in Plant Metabolism. Front Microbiol 2019; 10:1208. [PMID: 31191508 PMCID: PMC6546907 DOI: 10.3389/fmicb.2019.01208] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/13/2019] [Indexed: 12/16/2022] Open
Abstract
The fungal endophyte Gilmaniella sp. AL12 can establish a beneficial association with the medicinal herb Atractylodes lancea, and improve plant growth and sesquiterpenoids accumulation, which is termed “double promotion.” Our previous studies have uncovered the underling primary mechanism based on some physiological evidences. However, a global understanding of gene or protein expression regulation in primary and secondary metabolism and related regulatory processes is still lacking. In this study, we employed transcriptomics and proteomics of Gilmaniella sp. AL12-inoculated and Gilmaniella sp. AL12-free plants to study the impact of endophyte inoculation at the transcriptional and translational levels. The results showed that plant genes involved in plant immunity and signaling were suppressed, similar to the plant response caused by some endophytic fungi and biotroph pathogen. The downregulated plant immunity may contribute to plant-endophyte beneficial interaction. Additionally, genes and proteins related to primary metabolism (carbon fixation, carbohydrate metabolism, and energy metabolism) tended to be upregulated after Gilmaniella sp. AL12 inoculation, which was consistent with our previous physiological evidences. And, Gilmaniella sp. AL12 upregulated genes involved in terpene skeleton biosynthesis, and upregulated genes annotated as β-farnesene synthase and β-caryophyllene synthase. Based on the above results, we proposed that endophyte-plant associations may improve production (biomass and sesquiterpenoids accumulation) by increasing the source (photosynthesis), expanding the sink (glycolysis and tricarboxylic acid cycle), and enhancing the metabolic flux (sesquiterpenoids biosynthesis pathway) in A. lancea. And, this study will help to further clarify plant-endophyte interactions.
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Affiliation(s)
- Jie Yuan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Wei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Kai Sun
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Meng-Jun Tang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Piao-Xue Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xia Li
- Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of Chinese National Center Rice Improvement, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Chuan-Chao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing, China
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36
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Nissinen R, Helander M, Kumar M, Saikkonen K. Heritable Epichloë symbiosis shapes fungal but not bacterial communities of plant leaves. Sci Rep 2019; 9:5253. [PMID: 30918316 PMCID: PMC6437304 DOI: 10.1038/s41598-019-41603-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/07/2019] [Indexed: 11/25/2022] Open
Abstract
Keystone microbial species have driven eco-evolutionary processes since the origin of life. However, due to our inability to detect the majority of microbiota, members of diverse microbial communities of fungi, bacteria and viruses have largely been ignored as keystone species in past literature. Here we tested whether heritable Epichloë species of pooidae grasses modulate microbiota of their shared host plant.
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Affiliation(s)
- Riitta Nissinen
- Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Jyväskylä, Finland.
| | - Marjo Helander
- Department of Biology, 20014 University of Turku, Turku, Finland
| | - Manoj Kumar
- Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Jyväskylä, Finland
| | - Kari Saikkonen
- Biodiversity Unit, 20014 University of Turku, Turku, Finland
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37
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Nagabhyru P, Dinkins RD, Schardl CL. Transcriptomics of Epichloë-Grass Symbioses in Host Vegetative and Reproductive Stages. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:194-207. [PMID: 30145935 DOI: 10.1094/mpmi-10-17-0251-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epichloë species are fungal symbionts (endophytes) of cool-season grasses that transmit vertically via inflorescence primordia (IP), ovaries (OV), and ultimately, embryos. Epichloë coenophiala, an endophyte of tall fescue (Schedonorus arundinaceus), provides multiple protective benefits to the grass. We conducted transcriptome analysis of the tall fescue-E. coenophiala symbiosis, comparing IP, OV, vegetative pseudostems (PS), and the lemma and palea (LP) (bracts) of the young floret. Transcriptomes of host OV and PS exhibited almost no significant differences attributable to endophyte presence or absence. Comparison of endophyte gene expression in different plant parts revealed numerous differentially expressed genes (DEGs). The 150 endophyte DEGs significantly higher in PS over OV included genes for alkaloid biosynthesis and sugar or amino acid transport. The 277 endophyte DEGs significantly higher in OV over PS included genes for protein chaperones (including most heat-shock proteins), trehalose synthesis complex, a bax inhibitor-1 protein homolog, the CLC chloride ion channel, catalase, and superoxide dismutase. Similar trends were apparent in the Brachypodium sylvaticum-Epichloë sylvatica symbiosis. Gene expression profiles in tall fescue IP and LP indicated that the endophyte transcriptome shift began early in host floral development. We discuss possible roles of the endophyte DEGs in colonization of reproductive grass tissues.
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Affiliation(s)
- Padmaja Nagabhyru
- 1 Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, U.S.A.; and
| | - Randy D Dinkins
- 2 USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY 40546, U.S.A
| | - Christopher L Schardl
- 1 Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, U.S.A.; and
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38
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Scott B, Green K, Berry D. The fine balance between mutualism and antagonism in the Epichloë festucae-grass symbiotic interaction. CURRENT OPINION IN PLANT BIOLOGY 2018; 44:32-38. [PMID: 29454183 DOI: 10.1016/j.pbi.2018.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 05/27/2023]
Abstract
Epichloë endophytes form mutualistic symbiotic associations with aerial tissues of temperate grasses. Intercalary growth of hyphae within the leaves enables fungal growth to be synchronized with host leaf growth, leading to formation of a highly structured and tightly regulated symbiotic network. Mutations in fungal genes that disrupt cell-cell fusion and other key signalling pathways lead to an antagonistic interaction characterized by unregulated growth of endophytic hyphae and detrimental effects on host growth. Transcriptome analysis of these mutant associations provides key insights into the regulation of the symbiosis. In nature a similar switch in growth occurs when hyphae transition into the sexual cycle forming stromata that abort host inflorescences. Endophyte infection of the grass host leads to a major reprogramming of host metabolism and alters host development. Changes in endophyte cell wall structure and the repertoire of effectors secreted into the host apoplast accompany establishment of a mutualistic interaction within the leaves.
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Affiliation(s)
- Barry Scott
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
| | - Kimberly Green
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Daniel Berry
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
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39
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Rahnama M, Johnson RD, Voisey CR, Simpson WR, Fleetwood DJ. The Global Regulatory Protein VelA Is Required for Symbiosis Between the Endophytic Fungus Epichloë festucae and Lolium perenne. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:591-604. [PMID: 29315021 DOI: 10.1094/mpmi-11-17-0286-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Epichloë species fungi form bioprotective endophytic symbioses with many cool-season grasses, including agriculturally important forage grasses. Despite its importance, relatively little is known about the molecular details of the interaction and the regulatory genes involved. The conserved velvet-domain protein VelA (or VeA) is a global regulator of a number of cellular and developmental functions in fungi. In this study, the E. festucae velA gene was functionally characterized in vitro and during interaction with perennial ryegrass. The velA gene is required in E. festucae for resistance to osmotic and cell wall-damaging stresses, repression of conidiation, and normal hyphal morphology during nutrient-limited in-vitro conditions. Expression of velA in E. festucae is light- and nitrogen-dependent and is tissue-specific in mature infected plants. In-planta studies showed that velA is required in E. festucae for a compatible interaction. Inoculating seedlings with mutant ΔvelA induced callose deposition and H2O2 production, and a high level of seedling death was observed. In surviving plants infected with ΔvelA mutant fungi, plants were stunted and we observed increased biomass and invasion of vascular bundles. Overall, this work characterizes a key fungal regulatory factor in this increasingly important model symbiotic association.
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Affiliation(s)
- M Rahnama
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
- 2 School of Biological Sciences, University of Auckland, New Zealand
| | - R D Johnson
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - C R Voisey
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - W R Simpson
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - D J Fleetwood
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
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40
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Irizarry I, White J. Bacillus amyloliquefaciens
alters gene expression,
ROS
production and lignin synthesis in cotton seedling roots. J Appl Microbiol 2018; 124:1589-1603. [DOI: 10.1111/jam.13744] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/23/2018] [Accepted: 02/15/2018] [Indexed: 01/09/2023]
Affiliation(s)
- I. Irizarry
- Department of Plant Biology Rutgers University New Brunswick NJ USA
- Escuela de Ciencias Naturales y Tecnología Universidad del Turabo Gurabo Puerto Rico
| | - J.F. White
- Department of Plant Biology Rutgers University New Brunswick NJ USA
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41
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Ma X, Keller B, McDonald BA, Palma-Guerrero J, Wicker T. Comparative Transcriptomics Reveals How Wheat Responds to Infection by Zymoseptoria tritici. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:420-431. [PMID: 29090630 DOI: 10.1094/mpmi-10-17-0245-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The fungus Zymoseptoria tritici causes septoria tritici blotch (STB) on wheat, an important disease globally and the most damaging wheat disease in Europe. Despite the global significance of STB, the molecular basis of wheat defense against Z. tritici is poorly understood. Here, we use a comparative transcriptomic study to investigate how wheat responds to infection by four distinct strains of Z. tritici. We examined the response of wheat across the entire infection cycle, identifying both shared responses to the four strains and strain-specific responses. We found that the early asymptomatic phase is characterized by strong upregulation of genes encoding receptor-like kinases and pathogenesis-related proteins, indicating the onset of a defense response. We also identified genes that were differentially expressed among the four fungal strains, including genes related to defense. Genes involved in senescence were induced during both the asymptomatic phase and at late stages of infection, suggesting manipulation of senescence processes by both the plant and the pathogen. Our findings illustrate the need, when identifying important genes affecting disease resistance in plants, to include multiple pathogen strains.
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Affiliation(s)
- Xin Ma
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Beat Keller
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Bruce A McDonald
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Javier Palma-Guerrero
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Thomas Wicker
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
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42
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Bastías DA, Alejandra Martínez-Ghersa M, Newman JA, Card SD, Mace WJ, Gundel PE. The plant hormone salicylic acid interacts with the mechanism of anti-herbivory conferred by fungal endophytes in grasses. PLANT, CELL & ENVIRONMENT 2018; 41:395-405. [PMID: 29194664 DOI: 10.1111/pce.13102] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/06/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
The plant hormone salicylic acid (SA) is recognized as an effective defence against biotrophic pathogens, but its role as regulator of beneficial plant symbionts has received little attention. We studied the relationship between the SA hormone and leaf fungal endophytes on herbivore defences in symbiotic grasses. We hypothesize that the SA exposure suppresses the endophyte reducing the fungal-produced alkaloids. Because of the role that alkaloids play in anti-herbivore defences, any reduction in their production should make host plants more susceptible to herbivores. Lolium multiflorum plants symbiotic and nonsymbiotic with the endophyte Epichloë occultans were exposed to SA followed by a challenge with the aphid Rhopalosiphum padi. We measured the level of plant resistance to aphids, and the defences conferred by endophytes and host plants. Symbiotic plants had lower concentrations of SA than did the nonsymbiotic counterparts. Consistent with our prediction, the hormonal treatment reduced the concentration of loline alkaloids (i.e., N-formyllolines and N-acetylnorlolines) and consequently decreased the endophyte-conferred resistance against aphids. Our study highlights the importance of the interaction between the plant immune system and endophytes for the stability of the defensive mutualism. Our results indicate that the SA plays a critical role in regulating the endophyte-conferred resistance against herbivores.
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Affiliation(s)
- Daniel A Bastías
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - M Alejandra Martínez-Ghersa
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Jonathan A Newman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Stuart D Card
- Forage Science, AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North, 4442, New Zealand
| | - Wade J Mace
- Forage Science, AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North, 4442, New Zealand
| | - Pedro E Gundel
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
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43
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Slaughter LC, Nelson JA, Carlisle E, Bourguignon M, Dinkins RD, Phillips TD, McCulley RL. Climate change and Epichloë coenophiala association modify belowground fungal symbioses of tall fescue host. FUNGAL ECOL 2018. [DOI: 10.1016/j.funeco.2017.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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44
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Talukder SK, Saha MC. Toward Genomics-Based Breeding in C3 Cool-Season Perennial Grasses. FRONTIERS IN PLANT SCIENCE 2017; 8:1317. [PMID: 28798766 PMCID: PMC5526908 DOI: 10.3389/fpls.2017.01317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 07/12/2017] [Indexed: 05/13/2023]
Abstract
Most important food and feed crops in the world belong to the C3 grass family. The future of food security is highly reliant on achieving genetic gains of those grasses. Conventional breeding methods have already reached a plateau for improving major crops. Genomics tools and resources have opened an avenue to explore genome-wide variability and make use of the variation for enhancing genetic gains in breeding programs. Major C3 annual cereal breeding programs are well equipped with genomic tools; however, genomic research of C3 cool-season perennial grasses is lagging behind. In this review, we discuss the currently available genomics tools and approaches useful for C3 cool-season perennial grass breeding. Along with a general review, we emphasize the discussion focusing on forage grasses that were considered orphan and have little or no genetic information available. Transcriptome sequencing and genotype-by-sequencing technology for genome-wide marker detection using next-generation sequencing (NGS) are very promising as genomics tools. Most C3 cool-season perennial grass members have no prior genetic information; thus NGS technology will enhance collinear study with other C3 model grasses like Brachypodium and rice. Transcriptomics data can be used for identification of functional genes and molecular markers, i.e., polymorphism markers and simple sequence repeats (SSRs). Genome-wide association study with NGS-based markers will facilitate marker identification for marker-assisted selection. With limited genetic information, genomic selection holds great promise to breeders for attaining maximum genetic gain of the cool-season C3 perennial grasses. Application of all these tools can ensure better genetic gains, reduce length of selection cycles, and facilitate cultivar development to meet the future demand for food and fodder.
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45
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Schmid J, Day R, Zhang N, Dupont PY, Cox MP, Schardl CL, Minards N, Truglio M, Moore N, Harris DR, Zhou Y. Host Tissue Environment Directs Activities of an Epichloë Endophyte, While It Induces Systemic Hormone and Defense Responses in Its Native Perennial Ryegrass Host. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:138-149. [PMID: 28027026 DOI: 10.1094/mpmi-10-16-0215-r] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Increased resilience of pasture grasses mediated by fungal Epichloë endophytes is crucial to pastoral industries. The underlying mechanisms are only partially understood and likely involve very different activities of the endophyte in different plant tissues and responses of the plant to these. We analyzed the transcriptomes of Epichloë festucae and its host, Lolium perenne, in host tissues of different function and developmental stages. The endophyte contributed approximately 10× more to the transcriptomes than to the biomass of infected tissues. Proliferating mycelium in growing host tissues highly expressed genes involved in hyphal growth. Nonproliferating mycelium in mature plant tissues, transcriptionally equally active, highly expressed genes involved in synthesizing antiherbivore compounds. Transcripts from the latter accounted for 4% of fungal transcripts. Endophyte infection systemically but moderately increased transcription of L. perenne genes with roles in hormone biosynthesis and perception as well as stress and pathogen resistance while reducing expression of genes involved in photosynthesis. There was a good correlation between transcriptome-based observations and physiological observations. Our data indicate that the fitness-enhancing effects of the endophyte are based both on its biosynthetic activities, predominantly in mature host tissues, and also on systemic alteration of the host's hormonal responses and induction of stress response genes. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- Jan Schmid
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
| | - Robert Day
- 2 School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Ningxin Zhang
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
| | - Pierre-Yves Dupont
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
| | - Murray P Cox
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
| | - Christopher L Schardl
- 3 Department of Plant Pathology, University of Kentucky, Lexington 40546-0312, U.S.A
| | - Niki Minards
- 4 Manawatu Microscopy and Imaging Centre, Palmerston North 4410, New Zealand
| | - Mauro Truglio
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
| | - Neil Moore
- 5 Computer Science Department, University of Kentucky; and
| | - Daniel R Harris
- 6 Institute for Pharmaceutical Outcomes & Policy, University of Kentucky
| | - Yanfei Zhou
- 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand
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