The Enlargement of the xylophilus Group in the Genus Bursaphelenchus

Filipiak

2014

Bursaphelenchus fagi sp. n. (Nematoda: Parasitaphelenchidae), an insect-pathogenic nematode in the Malpighian tubules of the bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae, Scolytinae), in European beech, Fagus silvatica L. Summary -Bursaphelenchus fagi sp. n. is described from the bark of European beech, Fagus silvatica. All propagative stages of the nematode are numerous in larval galleries of the beech bark beetle, Taphrorychus bicolor, while dauer juveniles aggregate in Malpighian tubules of adult beetles. The new species is characterised by the body length of 871 (763-1110) p m in female and 852 (718-992) /xmin male, very slender body (a = 56.8 (50.4-67.1) and 64.5 (56.5-73.8) in female and male, respectively), and spicules 15.2 (14.0-17.0) p m long. The extended anterior vulval lip in female, lateral fields with four incisures, and number (7) and arrangement of male caudal papillae may indicate that B. fagi sp. n. is closely related to the xylophilus group. It differs from this group by the relatively small, claw like spicules with narrow capitulum, indistinct condylus in almost continuous line with dorsal lamina, and lack of distinct cucullus at the spicule tip. The close relation of B. fagi sp. n. with the xylophilus group has been confirmed by DNA sequencing and phylogenetic analysis of the 28S rDNA region. Bursaphelenchus fagi sp. n. most closely resembles B. tokyoensis and B. idius, but can be separated by differences in the arrangement of the male caudal papillae, a unique feature for each species. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). The mass presence of dauer juveniles of B. fagi sp. n. in Malpighian tubules of adult T. bicolor leads to degradation of the tubule cellular epithelium and local expansion of its basement membrane. These changes clearly indicate direct pathogenicity of the nematode to its vector insect. In laboratory rearing, B. fagi sp. n. can grow and reproduce on Botryotinia fuckeliana cultures.

Section: Discussionmentioning

confidence: 87%

Section: Type Habitat and Localitymentioning

confidence: 87%

Bursaphelenchus fagi sp. n. (Nematoda: Parasitaphelenchidae), an insect-pathogenic nematode in the Malpighian tubules of the bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae, Scolytinae), in European beech, Fagus silvatica L.

Filipiak

2014

“…n. is most closely related to species of the xylophilus group (sensu Braasch, 2008) and can be easily separated from all other Bursa phelenchus species, including those that partially share morphological characteristics of the xylophilus group (Ryss et al, 2005;Braasch et al, 2009).…”

Section: Diagnosis and Relationshipsmentioning

confidence: 97%

“…), in small-leaved lime, Tilia cordata Mill. The nematode presented all the morpho logical characters listed for the xylophilus group sensu Braasch (2008) but differed in spicule shape and size. The examined populations could not be precisely assigned to any of the known Bursaphelenchus species.…”

Section: Toinalak and T Malewskimentioning

confidence: 99%

Bursaphelenchus tiliae sp. n. (Nematoda: Parasitaphelenchidae), a nematode associate of the bark beetle Ernoporus tiliae (Panz.) (Coleoptera: Curculionidae, Scolytinae), in small-leaved lime, Tilia cordata Mill.

Malewski

2014

Bursaphelenchus tiliae sp. n. (Nematoda: Parasitaphelenchidae), a nematode associate of the bark beetle Ernoporus tiliae (Panz.) (Coleoptera: Curculionidae, Scolytinae), in small-leaved lime, Tilia cordata Mill. Summary -Bursaphelenchus tiliae sp. n. is described from the bark of dead branches of the small-leaved lime, Tilia cordata, infested with the lime bark beetle, Ernoporus tiliae. The nematode adults and propagative juveniles were present in larval galleries, while dispersal dauer juveniles colonised the Malpighian tubules of adult beetles. Bursaphelenchus tiliae sp. n. is characterised by the body length of 664 (568-817) /zm in female and 622 (515-754) gm in male, moderately slender body (a = 41.0 (34.7-47.9) and 43.1 (37.8-51.9) in female and male, respectively), and spicules 20.0 (18.1-21.8) prolong. The extended anterior vulval lip in female, lateral fields with four incisures, long post-uterine sac, and number (7) and arrangement of male caudal papillae, may indicate that B. tiliae sp. n. is closely related to the xylophilus group. It differs from this group by smaller, arcuate spicules with relatively short rostrum, narrow capitulum (5.2-6.9 pm ), and indistinct condylus in an almost continuous fine with dorsal lamina. Distal third of spicule dorsal contour is usually almost straight. The spicules have a distinct, disk-like cucullus at the terminus. The status of the new species is confirmed by the unique molecular profile of the ITS region (ITS-RFLP) and its close relation to the xylophilus group by DNA sequencing and phylogenetic analysis of the 28S rDNA region. The presence of B. tiliae sp. n. dauer juveniles in Malpighian tubules of their vector bark beetle, E. tiliae, caused limited pathogenicity expressed as a local expansion of the tubule basement membrane and partial degradation of the cellular epithelium.

“…However, in the last decade, the combined use of both morphological and molecular methods has improved diagnostic precision and as a consequence has facilitated the description of a number of new taxa within the genus. So far, ten species have been placed into the xylophilus group (Braasch, 2008), cording to recent suggestions by Braasch (2008), it seems to be identical to B. kolymensis.…”

mentioning

confidence: 99%

Description of Bursaphelenchus populi sp. n. (Nematoda: Parasitaphelenchidae), a new member of the xylophilus group from aspen, Populus tremula L., in Europe

Filipiak

2010

Bursaphelenchus populi sp. n. is described from dying and dead aspen trees, Populus tremula, in Poland. The nematode was found in trees infested with a long-horn beetle, Saperda perforata, and is vectored in the insect haemocoel. The characteristic morphology of male spicules, extended anterior vulval lip, lateral fields with four incisures, and number and arrangement of male caudal papillae, place B. populi sp. n. in the xylophilus group. Bursaphelenchus populi sp. n. can be separated from all other species in that group by the distinctive vulval flap, which is always bent with its distal half sunken in a conspicuous, sharp depression posterior to the vulva, and other morphological and morphometric characters, i.e., female tail shape, excretory pore position, spicule length (32.1 (25.7-37.0) μm (as measured along arc) and shape, and a relatively long (i.e., L = 1020 (909-1111) μm in females), and L = 850 (756-1055) μm in males), and slender body (a = 45.4 (40.2-52.4) and 42.0 (36.1-49.3) in female and male, respectively). The status of the new species is confirmed by the unique molecular profile of the ITS region (ITS-RFLP). DNA sequencing and phylogenetic analysis of 28S rDNA region placed the new species close to B. fraudulentus in the xylophilus group. In vitro cross-breeding of the new nematode with B. xylophilus, B. mucronatus, B. fraudulentus and B. doui revealed full reproductive incompatibility between these species. In laboratory experiments on 2-year-old seedlings B. populi sp. n. was specific to aspen. It did not develop on pine or oak and reproduced only in weakened or dead aspen seedlings. No pathogenicity to the tree host or vector insect was observed. In Botrytis cinerea PDA cultures, body dimensions were significantly altered in both sexes and female tail morphology differed when compared to individuals extracted from aspen wood.