<abstract xmlns="http://www.w3.org/1999/xhtml"><p>During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes have been found. Two poplar species, <italic>Populus angustifolia</italic> (narrowleaf cottonwood) and <italic>Populus trichocarpa</italic> (black cottonwood), are important ecological and genomic models now used in ongoing plant–pathogen–endophyte interaction studies. In this study, two different aphelenchid nematodes within surface-sterilized healthy leaves of these two <italic>Populus</italic> spp. in northwestern North America were discovered. Nematodes were identified and characterized microscopically and molecularly with 28S ribosomal RNA (rRNA) and 18S rRNA molecular markers. From <italic>P. angustifolia, Aphelenchoides saprophilus</italic> was inferred to be closest to another population of <italic>A. saprophilus</italic> among sequenced taxa in the 18S tree. From <italic>P. trichocarpa, Laimaphelenchus heidelbergi</italic> had a 28S sequence only 1 bp different from that of a Portuguese population, and 1 bp different from the original Australian type population. The 28S and 18S rRNA trees of <italic>Aphelenchoides</italic> and <italic>Laimaphelenchus</italic> species indicated <italic>L. heidelbergi</italic> failed to cluster with three other <italic>Laimaphelenchus</italic> species, including the type species of the genus. Therefore, we support a conservative definition of the genus <italic>Laimaphelenchus</italic>, and consider these populations to belong to <italic>Aphelenchoides</italic>, amended as <italic>Aphelenchoides heidelbergi</italic> n. comb. This is the first report of these nematode species from within aboveground leaves. The presence of these fungal-feeding nematodes can affect the balance of endophytic fungi, which are important determinants of plant health.</p></abstract>

During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes have been found. Two poplar species, Populus angustifolia (narrowleaf cottonwood) and Populus trichocarpa (black cottonwood), are important ecological and genomic models now used in ongoing plant–pathogen–endophyte interaction studies. In this study, two different aphelenchid nematodes within surface-sterilized healthy leaves of these two Populus spp. in northwestern North America were discovered. Nematodes were identified and characterized microscopically and molecularly with 28S ribosomal RNA (rRNA) and 18S rRNA molecular markers. From P. angustifolia, Aphelenchoides saprophilus was inferred to be closest to another population of A. saprophilus among sequenced taxa in the 18S tree. From P. trichocarpa, Laimaphelenchus heidelbergi had a 28S sequence only 1 bp different from that of a Portuguese population, and 1 bp different from the original Australian type population. The 28S and 18S rRNA trees of Aphelenchoides and Laimaphelenchus species indicated L. heidelbergi failed to cluster with three other Laimaphelenchus species, including the type species of the genus. Therefore, we support a conservative definition of the genus Laimaphelenchus, and consider these populations to belong to Aphelenchoides, amended as Aphelenchoides heidelbergi n. comb. This is the first report of these nematode species from within aboveground leaves. The presence of these fungal-feeding nematodes can affect the balance of endophytic fungi, which are important determinants of plant health.

Morphological and Molecular Characterization of Two <italic>Aphelenchoides</italic> Endophytic in Poplar Leaves

Henry A. Wallace Beltsville Agricultural Research Center

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Morphological and Molecular Characterization of Two  Endophytic in Poplar Leaves

During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes have been found. Two poplar species, Populus...

Morphological and Molecular Characterization of Two Aphelenchoides Endophytic in Poplar Leaves

Published Online: Jul 21, 2017

Page range: 28 - 33

Received: Sep 30, 2014

DOI: https://doi.org/10.21307/jofnem-2017-006

Keywords
nematode ecology, phylogeny, ribosomal DNA, systematics, taxonomy

© 2016 Lynn K. Carta et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Morphological and Molecular Characterization of Two Aphelenchoides Endophytic in Poplar Leaves

Published Online: Jul 21, 2017

Page range: 28 - 33

Received: Sep 30, 2014

DOI: https://doi.org/10.21307/jofnem-2017-006

Keywordsnematode ecology, phylogeny, ribosomal DNA, systematics, taxonomy

© 2016 Lynn K. Carta et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
nematode ecology, phylogeny, ribosomal DNA, systematics, taxonomy