1
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Hu S, Jin M, Xu Y, Wu Q, Jiang Q, Ma J, Zhang Y, Qi P, Chen G, Jiang Y, Zheng Y, Wei Y, Xu Q. Deacetylation of chitin oligomers by Fusarium graminearum polysaccharide deacetylase suppresses plant immunity. MOLECULAR PLANT PATHOLOGY 2023; 24:1495-1509. [PMID: 37746915 PMCID: PMC10632789 DOI: 10.1111/mpp.13387] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/29/2023] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Chitin is a long-chain polymer of β-1,4-linked N-acetylglucosamine that forms rigid microfibrils to maintain the hyphal form and protect it from host attacks. Chitin oligomers are first recognized by the plant receptors in the apoplast region, priming the plant's immune system. Here, seven polysaccharide deacetylases (PDAs) were identified and their activities on chitin substrates were investigated via systematic characterization of the PDA family from Fusarium graminearum. Among these PDAs, FgPDA5 was identified as an important virulence factor and was specifically expressed during pathogenesis. ΔFgpda5 compromised the pathogen's ability to infect wheat. The polysaccharide deacetylase structure of FgPDA5 is essential for the pathogenicity of F. graminearum. FgPDA5 formed a homodimer and accumulated in the plant apoplast. In addition, FgPDA5 showed a high affinity toward chitin substrates. FgPDA5-mediated deacetylation of chitin oligomers prevented activation of plant defence responses. Overall, our results identify FgPDA5 as a polysaccharide deacetylase that can prevent chitin-triggered host immunity in plant apoplast through deacetylation of chitin oligomers.
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Affiliation(s)
- Su Hu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Minxia Jin
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Yangjie Xu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Qin Wu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Qiantao Jiang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Jian Ma
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Yazhou Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Pengfei Qi
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Guoyue Chen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Yunfeng Jiang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Youliang Zheng
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Yuming Wei
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
| | - Qiang Xu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityChengduChina
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2
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Bastías DA, Balestrini R, Pollmann S, Gundel PE. Environmental interference of plant-microbe interactions. PLANT, CELL & ENVIRONMENT 2022; 45:3387-3398. [PMID: 36180415 PMCID: PMC9828629 DOI: 10.1111/pce.14455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Environmental stresses can compromise the interactions of plants with beneficial microbes. In the present review, experimental results showing that stresses negatively affect the abundance and/or functionality of plant beneficial microbes are summarized. It is proposed that the environmental interference of these plant-microbe interactions is explained by the stress-mediated induction of plant signalling pathways associated with defence hormones and reactive oxygen species. These plant responses are recognized to regulate beneficial microbes within plants. The direct negative effect of stresses on microbes may also contribute to the environmental regulation of these plant mutualisms. It is also posited that, in stress situations, beneficial microbes harbour mechanisms that contribute to maintain the mutualistic associations. Beneficial microbes produce effector proteins and increase the antioxidant levels in plants that counteract the detrimental effects of plant stress responses on them. In addition, they deliver specific stress-protective mechanisms that assist to their plant hosts to mitigate the negative effects of stresses. Our study contributes to understanding how environmental stresses affect plant-microbe interactions and highlights why beneficial microbes can still deliver benefits to plants in stressful environments.
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Affiliation(s)
- Daniel A. Bastías
- AgResearch LimitedGrasslands Research CentrePalmerston NorthNew Zealand
| | | | - Stephan Pollmann
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)–Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA/CSIC)Campus de MontegancedoMadridSpain
- Departamento de Biotecnología‐Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de BiosistemasUniversidad Politécnica de Madrid (UPM)MadridSpain
| | - Pedro E. Gundel
- IFEVA, CONICET, Universidad de Buenos AiresFacultad de AgronomíaBuenos AiresArgentina
- Centro de Ecología Integrativa, Instituto de Ciencias BiológicasUniversidad de TalcaTalcaChile
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3
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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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4
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Miller TA, Hudson DA, Johnson RD, Singh JS, Mace WJ, Forester NT, Maclean PH, Voisey CR, Johnson LJ. Dissection of the epoxyjanthitrem pathway in Epichloë sp. LpTG-3 strain AR37 by CRISPR gene editing. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:944234. [PMID: 37746172 PMCID: PMC10512260 DOI: 10.3389/ffunb.2022.944234] [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: 05/14/2022] [Accepted: 07/18/2022] [Indexed: 09/26/2023]
Abstract
Epichloë festucae var. lolii and Epichloë sp. LpTG-3 are filamentous fungal endophytes of perennial ryegrass (Lolium perenne) that have a substantial impact on New Zealand's agricultural economy by conferring biotic advantages to the host grass. Overall, Epichloë endophytes contribute NZ$200 million to the economy annually, with strain AR37 estimated to contribute NZ$3.6 billion to the New Zealand economy over a 20-year period. This strain produces secondary metabolites, including epoxyjanthitrems, which are a class of indole diterpenes, associated with the observed effects of AR37 on livestock and insect pests. Until very recently, AR37 was intractable to genetic modification but this has changed with the application of CRISPR-Cas9 based gene editing techniques. In this paper, gene inactivation by CRISPR-Cas9 was used to deconvolute the genetic basis for epoxyjanthitrem biosynthesis, including creating an AR37 strain that has been edited to remove the biosynthesis of all indole diterpenes. We show that gene editing of Epichloë can be achieved without off-target events or introduction of foreign DNA (footprint-less) through an AMA1-based plasmid that simultaneously expresses the CRISPR-Cas9 system and selectable marker. Genetic modification events in these transformants were investigated through genome sequencing and in planta chemistry.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Linda J. Johnson
- Grasslands Research Centre, AgResearch, Palmerston North, New Zealand
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5
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Berry D, Lee K, Winter D, Mace W, Becker Y, Nagabhyru P, Treindl AD, Bogantes EV, Young CA, Leuchtmann A, Johnson LJ, Johnson RD, Cox MP, Schardl CL, Scott B. Cross-species transcriptomics identifies core regulatory changes differentiating the asymptomatic asexual and virulent sexual life cycles of grass-symbiotic Epichloë fungi. G3 (BETHESDA, MD.) 2022; 12:jkac043. [PMID: 35191483 PMCID: PMC8982410 DOI: 10.1093/g3journal/jkac043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/07/2022] [Indexed: 02/04/2023]
Abstract
Fungi from the genus Epichloë form systemic endobiotic infections of cool season grasses, producing a range of host-protective natural products in return for access to nutrients. These infections are asymptomatic during vegetative host growth, with associations between asexual Epichloë spp. and their hosts considered mutualistic. However, the sexual cycle of Epichloë spp. involves virulent growth, characterized by the envelopment and sterilization of a developing host inflorescence by a dense sheath of mycelia known as a stroma. Microscopic analysis of stromata revealed a dramatic increase in hyphal propagation and host degradation compared with asymptomatic tissues. RNAseq was used to identify differentially expressed genes in asymptomatic vs stromatized tissues from 3 diverse Epichloë-host associations. Comparative analysis identified a core set of 135 differentially expressed genes that exhibited conserved transcriptional changes across all 3 associations. The core differentially expressed genes more strongly expressed during virulent growth encode proteins associated with host suppression, digestion, adaptation to the external environment, a biosynthetic gene cluster, and 5 transcription factors that may regulate Epichloë stroma formation. An additional 5 transcription factor encoding differentially expressed genes were suppressed during virulent growth, suggesting they regulate mutualistic processes. Expression of biosynthetic gene clusters for natural products that suppress herbivory was universally suppressed during virulent growth, and additional biosynthetic gene clusters that may encode production of novel host-protective natural products were identified. A comparative analysis of 26 Epichloë genomes found a general decrease in core differentially expressed gene conservation among asexual species, and a specific decrease in conservation for the biosynthetic gene cluster expressed during virulent growth and an unusual uncharacterized gene.
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Affiliation(s)
- Daniel Berry
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Kate Lee
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - David Winter
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Wade Mace
- AgResearch Ltd, Grasslands Research Centre, Palmerston North 4442, New Zealand
| | - Yvonne Becker
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn Institute, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Padmaja Nagabhyru
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA
| | - Artemis D Treindl
- Institute of Integrative Biology, ETH Zurich, 8092 Zürich, Switzerland
| | | | | | - Adrian Leuchtmann
- Institute of Integrative Biology, ETH Zurich, 8092 Zürich, Switzerland
| | | | | | - Murray P Cox
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | | | - Barry Scott
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
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6
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Hassing B, Candy A, Eaton CJ, Fernandes TR, Mesarich CH, Di Pietro A, Scott B. Localisation of phosphoinositides in the grass endophyte Epichloë festucae and genetic and functional analysis of key components of their biosynthetic pathway in E. festucae symbiosis and Fusarium oxysporum pathogenesis. Fungal Genet Biol 2022; 159:103669. [PMID: 35114379 DOI: 10.1016/j.fgb.2022.103669] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/15/2022] [Accepted: 01/27/2022] [Indexed: 11/24/2022]
Abstract
Phosphoinositides (PI) are essential components of eukaryotic membranes and function in a large number of signaling processes. While lipid second messengers are well studied in mammals and yeast, their role in filamentous fungi is poorly understood. We used fluorescent PI-binding molecular probes to localize the phosphorylated phosphatidylinositol species PI[3]P, PI[3,5]P2, PI[4]P and PI[4,5]P2 in hyphae of the endophyte Epichloë festucae in axenic culture and during interaction with its grass host Lolium perenne. We also analysed the roles of the phosphatidylinositol-4-phosphate 5-kinase MssD and the predicted phosphatidylinositol-3,4,5-triphosphate 3-phosphatase TepA, a homolog of the mammalian tumour suppressor protein PTEN. Deletion of tepA in E. festucae and in the root-infecting tomato pathogen Fusarium oxysporum had no impact on growth in culture or the host interaction phenotype. However, this mutation did enable the detection of PI[3,4,5]P3 in septa and mycelium of E. festucae and showed that TepA is required for chemotropism in F. oxysporum. The identification of PI[3,4,5]P3 in ΔtepA strains suggests that filamentous fungi are able to generate PI[3,4,5]P3 and that fungal PTEN homologs are functional lipid phosphatases. The F. oxysporum chemotropism defect suggests a conserved role of PTEN homologs in chemotaxis across protists, fungi and mammals.
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Affiliation(s)
- Berit Hassing
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Alyesha Candy
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Carla J Eaton
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand
| | - Tania R Fernandes
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba, Spain
| | - Carl H Mesarich
- Bio-Protection Research Centre, New Zealand; School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Antonio Di Pietro
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba, Spain
| | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; Bio-Protection Research Centre, New Zealand.
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7
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Noorifar N, Savoian MS, Ram A, Lukito Y, Hassing B, Weikert TW, Moerschbacher BM, Scott B. Chitin Deacetylases Are Required for Epichloë festucae Endophytic Cell Wall Remodeling During Establishment of a Mutualistic Symbiotic Interaction with Lolium perenne. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1181-1192. [PMID: 34058838 DOI: 10.1094/mpmi-12-20-0347-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Epichloë festucae forms a mutualistic symbiotic association with Lolium perenne. This biotrophic fungus systemically colonizes the intercellular spaces of aerial tissues to form an endophytic hyphal network and also grows as an epiphyte. However, little is known about the cell wall-remodeling mechanisms required to avoid host defense and maintain intercalary growth within the host. Here, we use a suite of molecular probes to show that the E. festucae cell wall is remodeled by conversion of chitin to chitosan during infection of L. perenne seedlings, as the hyphae switch from free-living to endophytic growth. When hyphae transition from endophytic to epiphytic growth, the cell wall is remodeled from predominantly chitosan to chitin. This conversion from chitin to chitosan is catalyzed by chitin deacetylase. The genome of E. festucae encodes three putative chitin deacetylases, two of which (cdaA and cdaB) are expressed in planta. Deletion of either of these genes results in disruption of fungal intercalary growth in the intercellular spaces of plants infected with these mutants. These results establish that these two genes are required for maintenance of the mutualistic symbiotic interaction between E. festucae and L. perenne.[Formula: see text] Copyright © 2021 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)
- Nazanin Noorifar
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Matthew S Savoian
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Arvina Ram
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Yonathan Lukito
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Berit Hassing
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
- Bioprotection Research Centre, Massey University, Palmerston North 4442, New Zealand
| | - Tobias W Weikert
- Institute for Biology and Biotechnology of Plants, Westfälische Wilhelms-Universität, Münster, Germany
| | - Bruno M Moerschbacher
- Institute for Biology and Biotechnology of Plants, Westfälische Wilhelms-Universität, Münster, Germany
| | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
- Bioprotection Research Centre, Massey University, Palmerston North 4442, New Zealand
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8
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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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9
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Passarge A, Demir F, Green K, Depotter JRL, Scott B, Huesgen PF, Doehlemann G, Misas Villamil JC. Host apoplastic cysteine protease activity is suppressed during the mutualistic association of Lolium perenne and Epichloë festucae. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3410-3426. [PMID: 33630999 DOI: 10.1093/jxb/erab088] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Plants secrete various defence-related proteins into the apoplast, including proteases. Papain-like cysteine proteases (PLCPs) are central components of the plant immune system. To overcome plant immunity and successfully colonize their hosts, several plant pathogens secrete effector proteins inhibiting plant PLCPs. We hypothesized that not only pathogens, but also mutualistic microorganisms interfere with PLCP-meditated plant defences to maintain endophytic colonization with their hosts. Epichloë festucae forms mutualistic associations with cool season grasses and produces a range of secondary metabolites that protect the host against herbivores. In this study, we performed a genome-wide identification of Lolium perenne PLCPs, analysed their evolutionary relationship, and classified them into nine PLCP subfamilies. Using activity-based protein profiling, we identified four active PLCPs in the apoplast of L. perenne leaves that are inhibited during endophyte interactions. We characterized the L. perenne cystatin LpCys1 for its inhibitory capacity against ryegrass PLCPs. LpCys1 abundance is not altered during the mutualistic interaction and it mainly inhibits LpCP2. However, since the activity of other L. perenne PLCPs is not sensitive to LpCys1, we propose that additional inhibitors, likely of fungal origin, are involved in the suppression of apoplastic PLCPs during E. festucae infection.
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Affiliation(s)
- Andrea Passarge
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Fatih Demir
- Central Institute for Engineering, Electronics and Analytics, Forschungszentrum Jülich, Jülich, Germany
| | - Kimberly Green
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
| | | | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, Forschungszentrum Jülich, Jülich, Germany
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Biochemistry, University of Cologne, Cologne, Germany
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10
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Wang R, Luo S, Clarke BB, Belanger FC. The Epichloë
festucae Antifungal Protein Efe-AfpA Is also a Possible Effector Protein Required for the Interaction of the Fungus with Its Host Grass Festuca rubra subsp. rubra. Microorganisms 2021; 9:140. [PMID: 33435432 PMCID: PMC7827515 DOI: 10.3390/microorganisms9010140] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/18/2020] [Accepted: 01/07/2021] [Indexed: 01/08/2023] Open
Abstract
Strong creeping red fescue (Festuca rubra subsp. rubra) is a commercially important low-maintenance turfgrass and is often naturally infected with the fungal endophyte Epichloë festucae. Epichloë spp. are endophytes of several cool-season grass species, often conferring insect resistance to the grass hosts due to the production of toxic alkaloids. In addition to insect resistance, a unique feature of the strong creeping red fescue/E. festucae symbiosis is the endophyte-mediated disease resistance to the fungal pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Such disease resistance is not a general feature of other grass/ Epichloë interactions. E. festucae isolates infecting red fescue have an antifungal protein gene Efe-afpA, whereas most other Epichloë spp. do not have a similar gene. The uniqueness of this gene suggests it may, therefore, be a component of the unique disease resistance seen in endophyte-infected red fescue. Here, we report the generation of CRISPR-Cas9 Efe-afpA gene knockouts with the goal of determining if absence of the protein in endophyte-infected Festuca rubra leads to disease susceptibility. However, it was not possible to infect plants with the knockout isolates, although infection was possible with the wild type E. festucae and with complemented isolates. This raises the interesting possibility that, in addition to having antifungal activity, the protein is required for the symbiotic interaction. The antifungal protein is a small secreted protein with high expression in planta relative to its expression in culture, all characteristics consistent with effector proteins. If Efe-AfpA is an effector protein it must be specific to certain interactions, since most Epichloë spp. do not have such a gene in their genomes.
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Affiliation(s)
- Ruying Wang
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (S.L.); (B.B.C.)
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Simin Luo
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (S.L.); (B.B.C.)
- College of Agro-Grassland Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Bruce B. Clarke
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (S.L.); (B.B.C.)
| | - Faith C. Belanger
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (S.L.); (B.B.C.)
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11
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Lukito Y, Lee K, Noorifar N, Green KA, Winter DJ, Ram A, Hale TK, Chujo T, Cox MP, Johnson LJ, Scott B. Regulation of host-infection ability in the grass-symbiotic fungus Epichloë festucae by histone H3K9 and H3K36 methyltransferases. Environ Microbiol 2020; 23:2116-2131. [PMID: 33350014 DOI: 10.1111/1462-2920.15370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/02/2020] [Accepted: 12/19/2020] [Indexed: 01/30/2023]
Abstract
Recent studies have identified key genes that control the symbiotic interaction between Epichloë festucae and Lolium perenne. Here we report on the identification of specific E. festucae genes that control host infection. Deletion of setB, which encodes a homologue of the H3K36 histone methyltransferase Set2/KMT3, reduced histone H3K36 trimethylation and led to severe defects in colony growth and hyphal development. The E. festucae ΔclrD mutant, which lacks the gene encoding the homologue of the H3K9 methyltransferase KMT1, displays similar developmental defects. Both mutants are completely defective in their ability to infect L. perenne. Alleles that complement the culture and plant phenotypes of both mutants also complement the histone methylation defects. Co-inoculation of either ΔsetB or ΔclrD with the wild-type strain enables these mutants to colonize the host. However, successful colonization by the mutants resulted in death or stunting of the host plant. Transcriptome analysis at the early infection stage identified four fungal candidate genes, three of which encode small-secreted proteins, that are differentially regulated in these mutants compared to wild type. Deletion of crbA, which encodes a putative carbohydrate binding protein, resulted in significantly reduced host infection rates by E. festucae.
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Affiliation(s)
- Yonathan Lukito
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand.,Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Kate Lee
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
| | - Nazanin Noorifar
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Kimberly A Green
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - David J Winter
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Arvina Ram
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Tracy K Hale
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Tetsuya Chujo
- Research and Development Center, Mayekawa Mfg. Co., Ltd, Tokyo, Japan
| | - Murray P Cox
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
| | - Linda J Johnson
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
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12
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St. Leger RJ, Wang JB. Metarhizium: jack of all trades, master of many. Open Biol 2020; 10:200307. [PMID: 33292103 PMCID: PMC7776561 DOI: 10.1098/rsob.200307] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
The genus Metarhizium and Pochonia chlamydosporia comprise a monophyletic clade of highly abundant globally distributed fungi that can transition between long-term beneficial associations with plants to transitory pathogenic associations with frequently encountered protozoans, nematodes or insects. Some very common 'specialist generalist' species are adapted to particular soil and plant ecologies, but can overpower a wide spectrum of insects with numerous enzymes and toxins that result from extensive gene duplications made possible by loss of meiosis and associated genome defence mechanisms. These species use parasexuality instead of sex to combine beneficial mutations from separate clonal individuals into one genome (Vicar of Bray dynamics). More weakly endophytic species which kill a narrow range of insects retain sexuality to facilitate host-pathogen coevolution (Red Queen dynamics). Metarhizium species can fit into numerous environments because they are very flexible at the genetic, physiological and ecological levels, providing tractable models to address how new mechanisms for econutritional heterogeneity, host switching and virulence are acquired and relate to diverse sexual life histories and speciation. Many new molecules and functions have been discovered that underpin Metarhizium associations, and have furthered our understanding of the crucial ecology of these fungi in multiple habitats.
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13
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Rocafort M, Fudal I, Mesarich CH. Apoplastic effector proteins of plant-associated fungi and oomycetes. CURRENT OPINION IN PLANT BIOLOGY 2020; 56:9-19. [PMID: 32247857 DOI: 10.1016/j.pbi.2020.02.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/08/2020] [Accepted: 02/14/2020] [Indexed: 05/23/2023]
Abstract
The outcome of an interaction between a plant and a fungus or an oomycete, whether compatibility or incompatibility, is often determined in the hostile extracellular spaces and matrices of the apoplast. Indeed, for compatibility to occur, many plant-associated fungi and oomycetes must first neutralize the apoplast, which is both monitored by plant cell-surface immune receptors, and enriched in plant (and frequently, competitor)-derived antimicrobial compounds. Research is highlighting the diverse roles that fungal and oomycete effector proteins play in the apoplast to promote compatibility, with most recent progress made towards understanding the role of these proteins in evading chitin-triggered immunity. Research is also showcasing the ability of apoplastic effector proteins to bring about incompatibility upon recognition by diverse plant cell-surface immune receptors, and the use of effectoromics to rapidly identify apoplastic effector protein-cell-surface immune receptor interactions.
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Affiliation(s)
- Mercedes Rocafort
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, 78850, Thiverval-Grignon, France
| | - Carl H Mesarich
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; Bio-Protection Research Centre, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
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14
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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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15
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Feldman D, Yarden O, Hadar Y. Seeking the Roles for Fungal Small-Secreted Proteins in Affecting Saprophytic Lifestyles. Front Microbiol 2020; 11:455. [PMID: 32265881 PMCID: PMC7105643 DOI: 10.3389/fmicb.2020.00455] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/03/2020] [Indexed: 11/24/2022] Open
Abstract
Small secreted proteins (SSPs) comprise 40–60% of the total fungal secretome and are present in fungi of all phylogenetic groups, representing the entire spectrum of lifestyles. They are characteristically shorter than 300 amino acids in length and have a signal peptide. The majority of SSPs are coded by orphan genes, which lack known domains or similarities to known protein sequences. Effectors are a group of SSPs that have been investigated extensively in fungi that interact with living hosts, either pathogens or mutualistic systems. They are involved in suppressing the host defense response and altering its physiology. Here, we aim to delineate some of the potential roles of SSPs in saprotrophic fungi, that have been bioinformatically predicted as effectors, and termed in this mini-review as “effector-like” proteins. The effector-like Ssp1 from the white-rot fungus Pleurotus ostreatus is presented as a case study, and its potential role in regulating the ligninolytic system, secondary metabolism, development, and fruiting body initiation are discussed. We propose that deciphering the nature of effector-like SSPs will contribute to our understanding of development and communication in saprophytic fungi, as well as help, to elucidate the origin, regulation, and mechanisms of fungal-host, fungal-fungal, and fungal-bacterial interactions.
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Affiliation(s)
- Daria Feldman
- Department of Plant Pathology and Microbiology, The R.H. Smith Faculty Agriculture, Food and Environment, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The R.H. Smith Faculty Agriculture, Food and Environment, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yitzhak Hadar
- Department of Plant Pathology and Microbiology, The R.H. Smith Faculty Agriculture, Food and Environment, The Hebrew University of Jerusalem, Jerusalem, Israel
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16
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Hume DE, Stewart AV, Simpson WR, Johnson RD. Epichloëfungal endophytes play a fundamental role in New Zealand grasslands. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1726415] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- David E. Hume
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - Alan V. Stewart
- PGG Wrightson Seeds Limited, Kimihia Research Centre, Lincoln, New Zealand
| | - Wayne R. Simpson
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
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17
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Hassing B, Eaton CJ, Winter D, Green KA, Brandt U, Savoian MS, Mesarich CH, Fleissner A, Scott B. Phosphatidic acid produced by phospholipase D is required for hyphal cell-cell fusion and fungal-plant symbiosis. Mol Microbiol 2020; 113:1101-1121. [PMID: 32022309 DOI: 10.1111/mmi.14480] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/23/2020] [Accepted: 01/27/2020] [Indexed: 12/15/2022]
Abstract
Although lipid signaling has been shown to serve crucial roles in mammals and plants, little is known about this process in filamentous fungi. Here we analyze the contribution of phospholipase D (PLD) and its product phosphatidic acid (PA) in hyphal morphogenesis and growth of Epichloë festucae and Neurospora crassa, and in the establishment of a symbiotic interaction between E. festucae and Lolium perenne. Growth of E. festucae and N. crassa PLD deletion strains in axenic culture, and for E. festucae in association with L. perenne, were analyzed by light-, confocal- and electron microscopy. Changes in PA distribution were analyzed in E. festucae using a PA biosensor and the impact of these changes on the endocytic recycling and superoxide production investigated. We found that E. festucae PldB, and the N. crassa ortholog, PLA-7, are required for polarized growth and cell fusion and contribute to ascospore development, whereas PldA/PLA-8 are dispensable for these functions. Exogenous addition of PA rescues the cell-fusion phenotype in E. festucae. PldB is also crucial for E. festucae to establish a symbiotic association with L. perenne. This study identifies a new component of the cell-cell communication and cell fusion signaling network for hyphal morphogenesis and growth of filamentous fungi.
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Affiliation(s)
- Berit Hassing
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Lincoln, New Zealand
| | - Carla J Eaton
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Lincoln, New Zealand
| | - David Winter
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Lincoln, New Zealand
| | - Kimberly A Green
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Lincoln, New Zealand
| | - Ulrike Brandt
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Matthew S Savoian
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Carl H Mesarich
- Bio-Protection Research Centre, Lincoln, New Zealand.,School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Andre Fleissner
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Barry Scott
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Lincoln, New Zealand
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18
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Rahnama M, Maclean P, Fleetwood DJ, Johnson RD. VelA and LaeA are Key Regulators of Epichloë festucae Transcriptomic Response during Symbiosis with Perennial Ryegrass. Microorganisms 2019; 8:microorganisms8010033. [PMID: 31878026 PMCID: PMC7023048 DOI: 10.3390/microorganisms8010033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 12/29/2022] Open
Abstract
VelA (or VeA) is a key global regulator in fungal secondary metabolism and development which we previously showed is required during the symbiotic interaction of Epichloë festucae with perennial ryegrass. In this study, comparative transcriptomic analyses of ∆velA mutant compared to wild-type E. festucae, under three different conditions (in culture, infected seedlings, and infected mature plants), were performed to investigate the impact of VelA on E. festucae transcriptome. These comparative transcriptomic studies 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 a number of small secreted proteins and a large number of proteins with no predictable functions. In addition, these results were compared with previous transcriptomic experiments that studied the impact of LaeA, another key global regulator of secondary metabolism and development that we have shown is important for E. festucae–perennial ryegrass interaction. The results showed that although VelA and LaeA regulate a subset of E. festucae genes in a similar manner, they also regulated many other genes independently of each other suggesting specialised roles.
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Affiliation(s)
- Mostafa Rahnama
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand; (P.M.); (D.J.F.)
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Correspondence: (M.R.); (R.D.J.)
| | - Paul Maclean
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand; (P.M.); (D.J.F.)
| | - Damien J. Fleetwood
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand; (P.M.); (D.J.F.)
- Biotelliga Ltd, Auckland 1052, New Zealand
| | - Richard D. Johnson
- AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand; (P.M.); (D.J.F.)
- Correspondence: (M.R.); (R.D.J.)
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19
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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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20
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Wu B, Cox MP. Greater genetic and regulatory plasticity of retained duplicates in Epichloë endophytic fungi. Mol Ecol 2019; 28:5103-5114. [PMID: 31614039 PMCID: PMC7004115 DOI: 10.1111/mec.15275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/11/2019] [Indexed: 12/12/2022]
Abstract
Gene duplicates can act as a source of genetic material from which new functions arise. Most duplicated genes revert to single copy genes and only a small proportion are retained. However, it remains unclear why some duplicate genes persist in the genome for an extended time. We investigate this question by analysing retained gene duplicates in the fungal genus Epichloë, ascomycete fungi that form close endophytic symbioses with their host grasses. Retained duplicates within this genus have two independent origins, but both long pre-date the origin and diversification of the genus Epichloë. We find that loss of retained duplicates within the genus is frequent and often associated with speciation. Retained duplicates have faster evolutionary rates (Ka) and show relaxed selection (Ka/Ks) compared to single copy genes. Both features are time-dependent. Through comparison of conspecific strains, we find greater evolutionary rates in coding regions and sequence divergence in regulatory regions of retained duplicates than single copy genes, with this pattern more pronounced for strains adapted to different grass host species. Consistent with this sequence divergence in regulatory regions, transcriptome analyses show greater expression variation of retained duplicates than single copy genes. This suggest that cis-regulatory changes make important contributions to the expression patterns of retained duplicates. Coupled with supporting observations from the model yeast Saccharomyces cerevisiae, these data suggest that genetic robustness and regulatory plasticity are common drivers behind the retention of duplicated genes in fungi.
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Affiliation(s)
- Baojun Wu
- Statistics and Bioinformatics Group, School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
| | - Murray P Cox
- Statistics and Bioinformatics Group, School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
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