RAPD variation in Gremmeniella abietina attacking Pinus sylvestris and Pinus contorta in northern Sweden

Abstract

Summary Genomic DNA from 81 isolates of Gremmeniella abietina collected from eleven plantations each of Pinus sylvestris and Pinus contorta in northern Sweden was studied using RAPD markers. The DNA variation between and within populations and the race and type distribution of G. abietina populations, causing symptoms similar to those of the North American race, were studied. The degree of genetic similarity was greater among G. abietina isolates from the same geographical areas than among isolates from different geographical areas, regardless of whether they were isolated from P. sylvestris or P. contorta. RAPD variation was greatest in the central parts of northern Sweden, suggesting that sexual reproduction has been somewhat more important there than further north or south. Only the RAPD fragments characteristic of the EU race of G. abietina were found in the material tested. The RAPD pattern described as characteristic of the northern type within the EU race was identified in 62% of the isolates. Divergence from the expected profile was due to differences in occurrence of fragments OPA12‐1400 and 12‐1500. This indicates that this part of the RAPD profile cannot be treated as diagnostic for the northern type. A conclusion of practical importance is that there is a considerable risk of G. abietina spreading from infected P. contorta plantations to adjacent areas with indigenous P. sylvestris regeneration, and vice versa, owing to the indicated lack of host‐specificity of the pathogen. It is possible, however, that host‐specific strains exist, but do not differ in their RAPD profiles.

Resistance toGremmeniella abietina(European race, large tree type) in introducedPinus contortaand nativePinus sylvestrisin Sweden

“…inoculum originated from adjacent P. sylvestris host trees should not influence the results because the same populations of G. abietina usually attack both P. sylvestris and P. contorta (Aitken 1993;Hansson et al 1996). The results are in accordance with recent studies in Quebec, Canada, where P. contorta and, to an even larger extent, P. banksiana were found to be highly resistant to the EU race of G. abietina ( = LTT).…”

“…ex Watts and P. sylvestris plantations in areas with harsh weather conditions and on sites originally covered with Picea abies (L.) Karst. (Karlman et al 1994;Hansson et al 1996). Like the NA race, it is confined to smaller trees and lower branches of trees covered by snow during winter.…”

Formation and growth of stem cankers caused by Gremmeniella abietina on young Pinus contorta

“…The symptoms of G. abietina on P. contorta in northern Sweden are similar to those of the North American race of the fungus, with canker formation and production of apothecia on trees 1±3 m high (LAFLAMME 1991). Investigations of genetic variation in G. abietina in northern Sweden recorded, however, only the Northern amplitype, identical to type B (UOTILA 1983) or small tree type (HELLGREN and Ho È GBERG 1995), of the European race in P. contorta (HAMELIN et al 1996;HANSSON et al 1996).…”

“…Investigations of genetic variation in G. abietina in northern Sweden recorded, however, only the Northern amplitype, identical to type B (UOTILA 1983) or small tree type (HELLGREN and Ho È GBERG 1995), of the European race in P. contorta (HAMELIN et al 1996;HANSSON et al 1996). Investigations of genetic variation in G. abietina in northern Sweden recorded, however, only the Northern amplitype, identical to type B (UOTILA 1983) or small tree type (HELLGREN and Ho È GBERG 1995), of the European race in P. contorta (HAMELIN et al 1996;HANSSON et al 1996).…”

Survival and vitality of Gremmeniella abietina on Pinus sylvestris slash in northern Sweden

“…Based on immunoblotting, types A and B are confirmed to be identical to LTT and STT respectively (Petä istö et al 1996). Initial investigations of genetic variation in G. abietina in northern Sweden recorded only the northern amplitype, similar to type B or STT (Hamelin et al 1996;Hansson et al 1996). During the latest outbreak in Sweden, 2001Sweden, -2003, however, symptoms on pole-sized P. sylvestris also in northern Sweden were similar to those earlier reported for the LTT with infections in the crown of middle-aged pines and production of pycnidia rather than apothecia (cf.…”