ARS | Publication request: Molecular and morphological characterization of Globodera populations from Oregon and Idaho

Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2011
Publication Date: July 17, 2011
Citation: Skantar, A.M., Handoo, Z.A., Carta, L.K., Chitwood, D.J. 2011. Molecular and morphological characterization of Globodera populations from Oregon and Idaho. Journal of Nematology. 43(3-4):282.

Technical Abstract: An unusual population of cyst nematode was found in soils collected from a Powell Butte, Oregon field with a cropping history including potatoes, wheat, other crops, and significant weed presence. Morphologically, these nematodes possessed characteristics that collectively set them apart from known Globodera species. Compared to G. pallida, the cyst body length was slightly longer and the second-stage juvenile stylet length was slightly shorter. In some individuals, the J2 stylet knob height was greater and the tail annules were more prominent than in G. pallida, and the tail abruptly narrowed with a slight constriction near the posterior third of the hyaline terminus. Compared to G. rostochiensis, the hyaline tail terminus had a larger number of refractive bodies, and cysts of this population had a smaller Granek’s ratio and fewer cuticular ridges between the anus and vulva. In some individuals, the tail termini of second-stage juveniles were more bluntly pointed, and the stylet knobs were more anteriorly directed with greater height. Unlike G. tabacum, the cyst wall often lacked a network-like pattern, and in some individuals, the juvenile tail terminus distinctly narrowed after a constriction. Molecularly, the populations from Oregon and Idaho were similar to each other but distinct from other species in the genus Globodera. Multiplex PCR of the ITS rDNA region gave results similar to G. tabacum; however, ITS-RFLP patterns were observed to have individual bands in common with G. rostochiensis and G. pallida. Phylogenetic analysis based on ITS1&2 rDNA sequences showed greatest similarity to populations from Argentina and Chile; together they form a moderately supported clade, distinct from G. rostochiensis, G. tabacum, G. mexicana, European type G. pallida, and several G. pallida populations from South America.