title: Deciphering the Niches of Colonisation of Vitis vinifera L. by the Esca-Associated Fungus Phaeoacremonium aleophilum Using a gfp Marked Strain and Cutting Systems.
abstract: BACKGROUND
  Esca disease has become a major threat for viticulture. Phaeoacremonium aleophilum is considered a pioneer of the esca complex pathosystem, but its colonisation behaviour inside plants remains poorly investigated.
  
  
  METHODS
  In this study, P. aleophilum::gfp7 colonisation was assessed six and twelve weeks post-inoculation in two different types of tissues: in the node and the internode of one year-old rooted cuttings of Cabernet Sauvignon. These processes of colonisation were compared with the colonisation by the wild-type strain using a non-specific lectin probe Alexa Fluor 488-WGA.
  
  
  RESULTS
  Data showed that six weeks post-inoculation of the internode, the fungus had colonised the inoculation point, the bark and xylem fibres. Bark, pith and xylem fibres were strongly colonised by the fungus twelve weeks post-inoculation and it can progress up to 8 mm from the point of inoculation using pith, bark and fibres. P. aleophilum was additionally detected in the lumen of xylem vessels in which tyloses blocked its progression. Different plant responses in specific tissues were additionally visualised. Inoculation of nodes led to restricted colonisation of P. aleophilum and this colonisation was associated with a plant response six weeks post-inoculation. The fungus was however detected in xylem vessels, bark and inside the pith twelve weeks post-inoculation.
  
  
  CONCLUSIONS
  These results demonstrate that P. aleophilum colonisation can vary according to the type of tissues and the type of spread using pith, bark and fibres. Woody tissues can respond to the injury and to the presence of this fungus, and xylem fibres play a key role in the early colonisation of the internode by P. aleophilum before the fungus can colonise xylem vessels.
authors.affiliation: Université de Toulouse, Equipe Vins Viticulture et Œnologie, Département des Sciences Agronomiques et Agroalimentaires, INP-EI Purpan, 75 voie du T.O.E.C. BP57611, Toulouse, France; University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria.
authors.forename: Romain
authors.initials: R
authors.lastname: Pierron
authors.affiliation: University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria; AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Gorfer
authors.affiliation: AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Berger
authors.affiliation: Université de Toulouse, Equipe Vins Viticulture et Œnologie, Département des Sciences Agronomiques et Agroalimentaires, INP-EI Purpan, 75 voie du T.O.E.C. BP57611, Toulouse, France.
authors.forename: Alban
authors.initials: A
authors.lastname: Jacques
authors.affiliation: AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria.
authors.forename: Angela
authors.initials: A
authors.lastname: Sessitsch
authors.affiliation: University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria; AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria.
authors.forename: Joseph
authors.initials: J
authors.lastname: Strauss
authors.affiliation: AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Compant
mesh_terms: D049452:Green Fluorescent Proteins / Q000235:genetics; D018613:Microscopy, Confocal; D020037:Sordariales / Q000235:genetics / Q000502:physiology*; D027843:Vitis / Q000382:microbiology*
chemical_list: D049452:Green Fluorescent Proteins