Research group leader Swedish University of Agricultural Sciences Uppsala, Uppsala Lan, Sweden
European forestry is threatened by the root, butt, and stem rots caused by the fungal pathogen complex Heterobasidion annosum s.l. Heterobasidion rots generate nearly 800 million euros in annual losses, and Sweden and Finland together account for 120 million euros of this damage. While fungal biocontrol products have been engineered for use in conifer forests affected by Heterobasidion, bacterial biocontrol products currently approved in Sweden contain Pseudomonas strains that do not originate from conifers or Fennoscandia. We hypothesize that local strains of Pseudomonas and the commonly occurring genus Sphingomonas originating from Swedish conifers are actually better adapted to persisting on their local conifer hosts relative to foreign isolates, and thus are improved candidates for evaluating biocontrol potential. To facilitate the bacterial culturing surveys of local spruce (Picea abies) sapwood and heartwood required to test this hypothesis, a simple, 3D-printed tool was designed to facilitate the rapid and aseptic homogenization of wooden cores produced from standard increment borers, and we additionally report on the distribution of endophytic culturable bacteria within spruce and Heterobasidion tissues. After supplementing local strains with antifungal biosynthesis pathways from marketed biocontrol products as necessary to level the playing field, we aim to experimentally compare biocontrol capabilities of local and unadapted bacteria.
