title: Molecular and Morphological Characterization of Xiphinema chambersi Population from Live Oak in Jekyll Island, Georgia, with Comments on Morphometric Variations.
abstract: A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, GA, is described using both morphological and molecular tools and compared with descriptions of type specimens. Initially, because of a few morphological differences, this nematode was thought to represent an undescribed species. However, on further examination, the morphometrics of the nematodes from live oak tend to agree with most of the morphometrics in the original description and redescription of X. chambersi except for few minor differences in V% relative to body length, slightly shorter stylet length, different c value, and the number of caudal pores. We consider these differences to be part of the normal variation within this species and accordingly image this new population of X. chambersi and redescribe the species. The new population is characterized by having females with a body length of 2.1 to 2.5 mm; lip region slightly rounded and set off from head; total stylet length 170 to 193 µm; vulva at 20.4% to 21.8% of body length; a monodelphic, posterior reproductive system; elongate, conoid tail with a blunt terminus and four pairs of caudal pores, of which two pairs are subdorsal and two subventral. Sequence data from the D2-D3 region of the 28S rRNA molecule subjected to GenBank sequence comparison using BLAST showed that the sequence had 96% and 99% similarity with X. chambersi from Alabama and Florida, respectively. Phylogenetic relationships of X. chambersi with other xiphinematids based on analysis of this DNA fragment are presented. This finding represents a new location of X. chambersi in Georgia on live oak for this species.
authors.affiliation: Nematology Laboratory, USDA, ARS, Building 010A, BARC-West, 10300 Baltimore Avenue, Beltsville, MD 20705.
authors.forename: Zafar A
authors.initials: ZA
authors.lastname: Handoo
authors.affiliation: Nematology Laboratory, USDA, ARS, Building 010A, BARC-West, 10300 Baltimore Avenue, Beltsville, MD 20705.
authors.forename: Lynn K
authors.initials: LK
authors.lastname: Carta
authors.affiliation: Nematology Laboratory, USDA, ARS, Building 010A, BARC-West, 10300 Baltimore Avenue, Beltsville, MD 20705.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Skantar
authors.affiliation: California Department of Food and Agriculture, Plant Pest Diagnostic Center, 3294 Meadowview Road, Sacramento, CA 95832.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Subbotin
authors.affiliation: Forest Service, Southern Research Station, 320 Green Street, Athens, GA 30602.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Fraedrich
keywords: 28S rRNA; Xiphinema chambersi; live oak; morphology; morphometrics; phylogeny; redescription; taxonomy; tree