title: Host Tissue Environment Directs Activities of an Epichloë Endophyte, While It Induces Systemic Hormone and Defense Responses in Its Native Perennial Ryegrass Host.
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 .
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Jan
authors.initials: J
authors.lastname: Schmid
authors.affiliation: 2 School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Robert
authors.initials: R
authors.lastname: Day
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Ningxin
authors.initials: N
authors.lastname: Zhang
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Dupont
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Murray P
authors.initials: MP
authors.lastname: Cox
authors.affiliation: 3 Department of Plant Pathology, University of Kentucky, Lexington 40546-0312, U.S.A.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Schardl
authors.affiliation: 4 Manawatu Microscopy and Imaging Centre, Palmerston North 4410, New Zealand.
authors.forename: Niki
authors.initials: N
authors.lastname: Minards
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Mauro
authors.initials: M
authors.lastname: Truglio
authors.affiliation: 5 Computer Science Department, University of Kentucky; and.
authors.forename: Neil
authors.initials: N
authors.lastname: Moore
authors.affiliation: 6 Institute for Pharmaceutical Outcomes & Policy, University of Kentucky.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Harris
authors.affiliation: 1 Institute of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D018744:DNA, Plant / Q000378:metabolism; D060026:Endophytes / Q000235:genetics / Q000502:physiology*; D004777:Environment; D055329:Epichloe / Q000235:genetics / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005800:Genes, Fungal; D060434:Herbivory; D054884:Host-Pathogen Interactions; D025301:Hyphae / Q000235:genetics; D008129:Lolium / Q000254:growth & development / Q000276:immunology* / Q000382:microbiology*; D016366:Open Reading Frames / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D013559:Symbiosis / Q000235:genetics; D014158:Transcription, Genetic; D059467:Transcriptome / Q000235:genetics
chemical_list: D018744:DNA, Plant; D010937:Plant Growth Regulators; D010940:Plant Proteins