title: Isolation studies reveal a shift in the cultivable microbiome of oak affected with Acute Oak Decline.
abstract: Acute Oak Decline is a syndrome within the Oak Decline complex in Britain. Profuse stem bleeding and larval galleries of the native buprestid, Agrilus biguttatus characterize the disease. A systematic study comparing healthy with diseased trees was undertaken. This work reports the result of isolations from healthy trees, diseased and non-symptomatic tissue within AOD affected trees, at five sites in England. Bacteria and fungi were identified using the DNA gyrase B gene, or ITS 1 sequencing. A significantly higher proportion of diseased tissues (82%) yielded more bacteria than either healthy (18%) or non-symptomatic tissue in diseased trees (33%). Overall bacterial community compositions varied at each site, but significant similarities were evident in diseased tissues at all sites. Enterobacteriaceae dominated in diseased trees whereas Pseudomonadaceae dominated healthy trees. Significant associations between diseased tissues and certain bacterial species occurred, implying that the cause of tissue necrosis was not due to random microbiota. Brenneria goodwinii and Gibbsiella quercinecans were key species consistently isolated from diseased tissue; Rahnella victoriana and an un-named Pseudomonas taxon were also frequently isolated from both healthy and diseased trees. Most fungi isolated were from the outer bark and had no significant association with tree health status. It was concluded that there was a shift in the cultivatable bacterial microbiome of diseased trees, with Enterobacteriaceae strongly represented in symptomatic but not healthy tissues. No single species dominated the isolations from diseased tissues and the tissue degradation in AOD is therefore likely to have a polymicrobial cause.
authors.affiliation: Forest Research, Centre for Ecosystems, Society and Biosecurity, Alice Holt Lodge, Surrey, GU10 4LH, United Kingdom. Electronic address: sandra.denman@forestry.gsi.gov.uk.
authors.forename: Sandra
authors.initials: S
authors.lastname: Denman
authors.affiliation: Forest Research, Centre for Ecosystems, Society and Biosecurity, Alice Holt Lodge, Surrey, GU10 4LH, United Kingdom; School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd, LL57 2UW, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Plummer
authors.affiliation: Forest Research, Centre for Ecosystems, Society and Biosecurity, Alice Holt Lodge, Surrey, GU10 4LH, United Kingdom.
authors.forename: Susan
authors.initials: S
authors.lastname: Kirk
authors.affiliation: Craigerne Drive, Peebles, Scottish Borders, EH45 9HN, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Peace
authors.affiliation: School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd, LL57 2UW, United Kingdom.
authors.forename: James E
authors.initials: JE
authors.lastname: McDonald
mesh_terms: D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D004739:England; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D005658:Fungi / Q000302:isolation & purification*; D010935:Plant Diseases / Q000382:microbiology*; D011548:Pseudomonadaceae / Q000302:isolation & purification*; D029963:Quercus / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014197:Trees / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial; D004271:DNA, Fungal; D012336:RNA, Ribosomal, 16S; D027081:DNA Gyrase
keywords: Acute Oak Decline; Brenneria goodwinii; Cultivatable bacterial microbiome; Enterobacteriaceae; Gibbsiella quercinecans; Oak; Polymicrobial disease; Rahnella victoriana