Research Highlights

2015

  • Dothistromin regulation by AflJ
    • Chettri et al. 2015. Fungal Biology.
    • A homologue of the aflatoxin regulator AflJ regulates dothistromin biosynthesi
    • DsAflJ mutants had reduced levels of dothistromin toxin and gene expressions
    • Overexpression of AflJ results in elevated levels of aflatoxin, but not dothistromin.
    • Species-specificity of AflJ was suggested by lack of cross-species complementation.
  • Dothistroma septosporum is the cause of a recent DNB epidemic on P. tecunumanii in Colombia. Within- and between-species susceptibility also reported.
    • Rodas et al. 2015 “Dothistroma Needle Blight: an emerging epidemic caused by Dothistroma septosporum in Colombia”. Plant Pathology.
    • P. tecunumanii low elevation provenances had the greatest susceptibility, followed by P. kesiya and P. oocarpa. Pinus maximinoi and high elevation P. tecunumanii had the lowest susceptibility.
  • Dothistroma septosporum spores only disperse short distances and during wet weather in northwest BC.
    • Boateng and Lewis 2015. Phytopathology.
    • Conidia were observed on spore traps from June to September during periods of rainfall.
    • It was rare to detect spores more than 2m away from inoculum sources.
    • The timing and number of conidia dispersed were strongly tied to the climatic variables, particularly rainfall and leaf wetness.
  • Abies ­- a new host genus for D. septosporum
    • Drenkhan et al. 2014. Forest Pathology 44, 250-254.
    • Estonia
    • Abies concolor and A. alba
  • Cedrus – a new host genus for D. septosporum
    • Mullett and Fraser in press. Forest Pathology.
    • UK – C. atlantica glauca in the field
    • C. atlantica glauca, C. libani and C. deodara in artificial inoculations
  • Storage of D. septosporum cultures under 10% glycerol at -80°C or water at 4°C recommended
    • Fraser et al. 2015. Forest Pathology.
  • DNB severity influenced by other fungi
    • Ridout and Newcombe 2015. Forest Ecology and Management 337, 153-160.
    • Inoculation of P. ponderosa in the field in Idaho, USA with other fungi
    • Penicillium goetzii was the sole antagonist and reduced disease severity by nearly 7% compared to control needles.
    • Four of the fungi (Sydowia polyspora, Bionectria ochroleuca, Penicillium raistrickii, and a culturable species of Elytroderma) acted as pathogen enablers, increasing disease severity 4.7%, 4.2%, 3.6%, and 2.5%, respectively.
  • Relative susceptibility of Scottish P. sylvestris populations varies between sites
    • Fraser et al. In review. Plant Pathology.
    • Natural infection of 6 Scottish populations on 2 Scottish sites.
    • Between site variation in relative susceptibilities may be caused by:
      • Local adaptation of P. sylvestris populations
      • Local adaptation of D. septosporum populations
  • Pinus sylvestris and P. contorta have similar susceptibility to DNB in Scotland
    • Fraser et al. in review. Forest Pathology.
    • In naturally infected field experiments in Scotland both P. contorta and P. sylvestris were less susceptible than P. nigra ssp. laricio, P. nigra ssp. nigra, P. muricata and P. ponderosa.
    • Artificial inoculation experiments under controlled conditions did not give consistent results and conflicted with those of field experiments.
    • No evidence for between-isolate variation in virulence or an interaction between D. septosporum isolate and host relative susceptibility.