Phylogeny of Gremmeniella spp. based on sequences of the 5.8s rDNA and internal transcribed spacer region Richard C. Hamelin and Jimmy Rail Abstract: Sequences in the 5.8s rDNA and internal transcribed spacer region were obtained for taxa belonging to Gremmeniella spp., and a phylogenetic analysis was carried out using parsimony and distance methods. A set of hypotheses concerning evolutionary relationships between members of that genus was tested. The hypothesis that all members of Gremmeniella abietina var. abietina are closely related was rejected. It appears that the Asian race is quite divergent from the European and North American races, but could be more closely related to G. abietina var. balsamea. The phylogeny 'was consistent with host specificity: members of G, abietina var. abietina generally do not infect Abies or Picea spp. but the Asian race occurs on Abies sachalinensis in Japan. The hypothesis that host specialization has created divergence within G. abietina var. balsamea was supported by our analysis because the levels of divergence between isolates originating from Picea spp. and Abies spp. were similar to those found between the North American and European races of G. abietina var. abietina. The hypothesis that greater divergence occurred between Gremrneniella abietina and Gremmeniella laricina than between G. abietina var. abietina and G. abietina var. balsamea was not supported. The level of divergence was as large between the two varieties within G. abietina as between the two species G. abietina and G. laricina. These results indicate that similar taxonomic levels should be applied to these three taxa. Key words: scleroderris canker, internal transcribed spacer (ITS). R6sum6 : Le gtne d'ADN ribosomique 5.8s et les rtgions internes non transcrites ont Ctt stquencts pour les esp&ces appartenant au genre Gremmeniellu; une analyse de phylogtnie a ensuite kt6 effectuee par les mtthodes de parsimonie et de distance pour tester des hypotheses concernant 1'Cvolution de ces espkces. L'hypothbe voulant que les membres de l'espkce Gremmeniella abietina var. ubietina foment un groupe lit par l'tvolution est rejette. La race asiatique est trks divergente des races nord-amtricaines et europtennes mais semble Etre plut6t like au groupe G. abietina var. balsamea. Ces rtsultats sont en accord avec la sgcificitk sur les essences h6te.s : les membres de G. abietina var. abierina attaquent rarement les Picea ou les Abies alors que la race asiatique a CtC isolte sur I'Abies sachalinensis au Japon. L'hypoth5se de spkcialisation sur l'kpinette et le sapin au sein de G. abietina var. balsamea est vkrifite par notre analyse. En effet, des taux de divergence semblables ont kt6 mesurts entre les souches de G. abietina var. balsumea sur le sapin et I'epinette et entre les races nord-arntricaines et europkennes de G. abietina var. ubietina. Cependant, l'hypoth5se de la prtsence de taux de divergence plus tlevks entre les deux esptces Gremmeniella laricina et Gremmeniella abietina, qu'entre les deux varittts, G. abietiriu var. abietina et G. abietina var. balsama n'est pas corroborte par nos donnCes. Des taux de divergence eleves ont 6ti dtcelCs aussi bien entre les variktis abietina et balsamea qu'entre les esp8ces G. abietina et G. lan'cina. Ces resultats suggtrent que des niveaux taxonomiques semblables devraient Etre appliquts aux groupes G. abietina var. abietina, G. abietina var. balsamea et G. Inricina. Mots clds : chancre sclCroderrien, rkgions internes non transcrites (ITS). Introduction the taxa in this genus has been problematic due in part to the Species belonging to the genus Gremmeniella cause serious diseases of conifers in Europe, Asia, and North America (Dorworth 1979; Gibbs 1983; Karlman et al. 1994; Lachance 1979; Laflamme and Lachance 1987; Ohman 1966; Setliff et al. 1975). The taxonomic status of some of Received June 18, 1996. R.C. Hamelin' and J. Rail. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, P. 0. Box 3800, 1055 rue du P.E. P.S., Sainte-Foy , QC G1V 4C7, Canada. ' Author to whom all correspondence should be addressed. e-mail: Hamelin@cfl. forestry.ca plasticity of morphological characters and because of the overlap between taxa. Our ability to recognize and classify members of this genus is important because some taxa are suspected of having been introduced into North America and possibly into Europe, and certification and quarantine pro- grams have been developed to prevent further spread or new introductions. Three species are recognized within this genus: Grem- meniella abietina (Lagerberg) Morelet, Gremmeniella lari- cina (Ettlinger) 0 . Petrini, L. E. Petrini, G. Laflamme & G. B. Ouellette, and Gremmeniella juniperina L. Holm & K. Holm. The latter two species appear to be restricted to single host genera, Lurk spp. and Juniperus spp., respec- tively. Gremmeniella abietina has a broader host range; it is Can. I. Bot. 75: 693 -698 (1997) @ 1997 NRC Cannda Can. J. Bot. Downloaded from www.nrcresearchpress.com by Guangzhou Jinan University on 06/05/13 For personal use only.