- Institutionen för skoglig mykologi och patologi, Sveriges lantbruksuniversitet
Samils N., Olson A., Stenlid J.
The necrotrophic pathogen Heterobasidion annosum sensu lato (Fr.) Bref. causes severe root rot on coniferous trees in the boreal and temperate forests. The annual economic losses caused by this fungus in Europe are estimated to at least 790 million C. In managed forests, the major route of infection is via stump surfaces from which the H. annosum s.l. grows through the roots and attacks adjacent healthy trees. A biocontrol method to reduce H. annosum s.l. infection is to apply the wood degrading fungus Phlebiopsis gigantea in a spore solution (Rotstop) directly on the freshly cut stumps immediately after cutting. We investigated the potential risk for a buildup in the capacity of H. annosum s.l. to resist overgrowth by P. gigantea. Wood blocks of Picea abies, precolonized with the two fungal species, were juxtaposed on top of agar and the overgrowth of the P. gigantea strain (Rotstop) on the H. annosum s.l. was measured periodically. We found a natural variation in Heterobasidion parviporum to resist overgrowth by P. gigantea. There was no difference between homo- and heterokaryotic strains. In a mapping population of 91 progenies from a H. annosum hybrid strain we were able to identify one quantitative trait locus (QTL) which controls the examined resistance capacity. We estimated the broad sense heritability to 0.336 for the capacity to resist the P. gigantea overgrowth. We conclude that there exists a theoretical risk for resistance build-up in the H. annosum s.l. population towards its biological control agent P. gigantea. (c) 2008 Elsevier Inc. All rights reserved.
Heterohasidion annosum s.l.; rotstop; Phlebiopsis gigantea; resistance; broad sense heritability; biological control
2008, Volym: 45, nummer: 3, sidor: 419-426