Heterobasidion annosum (Fr.:Fr.) Bref. coll. is one of the most damaging root and butt rot agents on conifers. In the summer of 1998, a Swiss stone pine (Pinus cembra L.), growing at 1900 m in a mixed spruce (Picea) and larch (Larix) forest in the Aosta Valley (NW Italian Alps), was found to be infected by both H. parviporum Niemelä & Korhonen and H. annosum sensu stricto. The pine (about 14 m tall and at least 75 yr old) was apparently asymptomatic. The stem, the stump and all the main roots showed internal decay and they were consecutively cut into 3-4 cm thick disks. After 8 days incubation, the fungus was isolated from all disks belonging to roots and stump and from disks taken up to 4 m above collar in the stem. The isolates were identified by PCR markers and by sexual mating tests with testers of each European H. annosum species. Somatic incompatibility tests between isolates were also performed to study the patterns of colonization of genotypes inside the tree. The stem and one root were colonized by H. parviporum while the other roots and most of the stump by H. annosum sensu stricto. They represented one genet each. The co-existence of different H. annosum species in the same tree has been only reported in Pinus ponderosa Dougl. ex Laws. in California (1) and in Picea abies (L.) Karst. in Europe (2). To our knowledge, this is the first report of H. annosum sensu stricto on P. cembra and of an European pine to be simultaneously infected by more than one species of H. annosum coll.

European pines may be simultaneously infected by more than one species of Heterobasidion.

GONTHIER, Paolo;NICOLOTTI, Giovanni
2002-01-01

Abstract

Heterobasidion annosum (Fr.:Fr.) Bref. coll. is one of the most damaging root and butt rot agents on conifers. In the summer of 1998, a Swiss stone pine (Pinus cembra L.), growing at 1900 m in a mixed spruce (Picea) and larch (Larix) forest in the Aosta Valley (NW Italian Alps), was found to be infected by both H. parviporum Niemelä & Korhonen and H. annosum sensu stricto. The pine (about 14 m tall and at least 75 yr old) was apparently asymptomatic. The stem, the stump and all the main roots showed internal decay and they were consecutively cut into 3-4 cm thick disks. After 8 days incubation, the fungus was isolated from all disks belonging to roots and stump and from disks taken up to 4 m above collar in the stem. The isolates were identified by PCR markers and by sexual mating tests with testers of each European H. annosum species. Somatic incompatibility tests between isolates were also performed to study the patterns of colonization of genotypes inside the tree. The stem and one root were colonized by H. parviporum while the other roots and most of the stump by H. annosum sensu stricto. They represented one genet each. The co-existence of different H. annosum species in the same tree has been only reported in Pinus ponderosa Dougl. ex Laws. in California (1) and in Picea abies (L.) Karst. in Europe (2). To our knowledge, this is the first report of H. annosum sensu stricto on P. cembra and of an European pine to be simultaneously infected by more than one species of H. annosum coll.
2002
86(7)
814
814
Heterobasidion; PCR; pines
P. GONTHIER; GARBELOTTO M; NICOLOTTI G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/22140
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