First report of Bursaphelenchus antoniae from Pinus strobus in the U.S

Abstract

Juvenile, female and male nematodes were discovered in wood chips of white pine Pinus strobus from Ashley Falls, MA. Initial observations suggested these nematodes might be PWN, but closer morphological and molecular characterization proved otherwise. Comparison of measured features with those in the literature indicated this nematode population had some unique characteristics. The specimens were identified as Bursaphelenchus antoniae Penas et al., 2006 based on 18S rDNA molecular sequence vs only 95% similarity with PWN B. xylophilus. Compared to the previously described Portuguese population of B. antoniae, the sequences generated for the MA population were 98.3% similar in the ITS1, 2 rDNA and 99.9% similar for 28S rDNA. There was 99.2% similarity between the COI sequences of the US and Portuguese isolates of B. antoniae. This population has morphology consistent with that of Penas et al., 2006; however, the female tail on this MA pine population is mucronate and more attenuated than in B. antoniae from Portuguese P. pinaster found in association with Hylobius sp. Ecological associations of both populations of B. antoniae are discussed.

Juvenile, female and male nematodes were discovered in wood chips of white pine Pinus strobus from Ashley Falls, MA. Initial observations suggested these nematodes might be PWN, but closer morphological and molecular characterization proved otherwise. Comparison of measured features with those in the literature indicated this nematode population had some unique characteristics. The specimens were identified as Bursaphelenchus antoniae Penas et al., 2006 based on 18S rDNA molecular sequence vs only 95% similarity with PWN B. xylophilus. Compared to the previously described Portuguese population of B. antoniae, the sequences generated for the MA population were 98.3% similar in the ITS1, 2 rDNA and 99.9% similar for 28S rDNA. There was 99.2% similarity between the COI sequences of the US and Portuguese isolates of B. antoniae. This population has morphology consistent with that of Penas et al., 2006; however, the female tail on this MA pine population is mucronate and more attenuated than in B. antoniae from Portuguese P. pinaster found in association with Hylobius sp. Ecological associations of both populations of B. antoniae are discussed.

Figure 1

A. Female body, B. Male body, C. Female Tail, D. Male Tail.

Figure 2

18S, MrBayes tree with posterior probabilities on branches of Bursaphelenchus antoniae and close relatives within the ‘B. hylobianum species group’ (in Clade I of Kanzaki et al., 2015) based on a Clustal W alignment implemented in Geneious ver. 7.1.7 (Biomatters, Auckland, NZ) using the MRBAYES plugin with Chain Length 1,100,000, Burnin 110,000, mean -LnL - 7438.56.

Figure 3

28S MrBayes tree with posterior probabilities on branches of B. antoniae based on a Clustal W alignment implemented in Geneious ver. 7.1.7 (Biomatters, Auckland, NZ) with Chain Length 1,100,000, Burnin 110,000, mean -LnL 3407.0.