Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: August 31, 2007
Publication Date: September 22, 2008
Citation: Handoo, Z.A., Carta, L.K., Skantar, A.M. 2008. Taxonomy, morphology and phylogenetics of coffee-associated root-lesion nematodes, Pratylenchus spp. In: Souza, R.M., editor. Plant-parasitic nematodes of coffee. Springer Science + Business Media B.V. p. 29-50.
Interpretive Summary: Interpretive summary:
Nematodes are microscopic worms that cause global crop losses exceeding $100 billion annually. Lesion nematodes are one of the most economically destructive groups of plant-parasitic nematodes. A major problem with accurate assessment of the damage caused by specific lesion nematodes reducing worldwide coffee production is the inadequate methodology for identifying nematodes. In the present study, ARS scientists from Beltsville, Maryland, compiled information on anatomical features for distinguishing eight previously described lesion nematode species on coffee from several other closely related nematode species. In addition, molecular markers were used to distinguish the same nematode species from each other. These anatomical and molecular results are significant because they provide the details necessary for scientists to correctly identify these species wherever they may occur in the world. This research will be used by scientists, action agencies, and extension agencies engaged in nematode research and control.
Although lesion nematodes (Pratylenchus species) can reduce coffee yield worldwide, methods for their identification are often difficult to implement. This review summarizes the diagnostic morphological features for distinguishing the eight previously described lesion nematode species associated with coffee from several closely related Pratylenchus spp. New light photomicrographs of heads and tails of various populations deposited in the USDA Nematode Collection at Beltsville illustrate these key features. An identification key to eight species of lesion nematodes attacking coffee was developed, and a compendium of the most important diagnostic characters for use in identification of the species provides a practical alternative and supplement to the key. In addition, an amended diagnosis, brief historical background, and geographic distribution of the genus, with information on problems for species identification, are discussed. An updated phylogeny of coffee lesion nematodes inferred from comparison of 28S and 18S ribosomal DNA sequences is presented.