2 resultados para 28S rDNA gene

em Repositório Científico da Universidade de Évora - Portugal


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During a field survey carried out on symptomatic maritime pine trees (Pinus pinaster) in Góis, central Portugal, Bursaphelenchus luxuriosae was isolated for the first time in Portugal, and in Europe. Identification of the nematodes was based on morphological characters and molecular analyses for this species. The general morphology of both females and males is in agreement with the original description for B. luxuriosae, namely the typical morphology of the male spicules and the conspicuous morphology of female tail. Species identification was confirmed through sequencing of the ITS rDNA region and the fragment spanning the D2/D3 domain of the 28S rDNA gene. This species belongs to the xylophilus-group and is the third species in this group known in Portugal. The nematodes were retrieved in small numbers (<100 nematodes/100 g dry wood), and no insect vector association could be established.

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Bursaphelenchus antoniae sp. n. is described and illustrated. Dauer juveniles were isolated from the body of the large pine weevil, Hylobius sp., collected from maritime pine (Pinus pinaster) stumps, in Portugal. Bursaphelenchus antoniae sp. n. was reared and maintained in P. pinaster wood segments and on Petri dish cultures of the fungi Botrytis cinerea and Monilinia fructicola. The new species is characterised by a relatively small body length of ca 583 μm (females) and 578 μm (males), a lateral field with two incisures, presence of a small vulval flap and a conoid female tail with a rounded or pointed terminus. Males have stout spicules with a disc-like cucullus and seven caudal papillae arranged as a single midventral precloacal papilla, one precloacal pair and two postcloacal pairs. In the character of the lateral field, B. antoniae sp. n. comes close to B. abietinus, B. rainulfi and B. hylobianum, whilst spicule characters place it within the piniperdae-group sensu Ryss et al. Morphologically, B. antoniae sp. n. is closest to B. hylobianum; the spicules of these two species having flattened, wing-like, alae on the distal third of the lamina. Bursaphelenchus antoniae sp. n. is distinguished from B. hylobianum on the arrangement of the caudal papillae (two vs three pairs). ITS-RFLP profiles and the failure to hybridise support the separation of the two species. Phylogenetic analysis of the new species, based on the 18S rDNA sequence, supports the inclusion of this new species in the B. hylobianum-group sensu Braasch. Sequence analysis of the 28S rDNA D2/D3 domain did not place the new species in a definite group.