Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Mycology and Nematology Genetic Diversity and Biology Laboratory » Research » Publications at this Location » Publication #321271
Title: Molecular and morphological characterization of a Xiphinema chambersi population from live oak trees in Jekyll Island, Georgia, with a redescription of the species and comments on its morphometric variations

Author
item Handoo, Zafar
item Carta, Lynn
item Skantar, Andrea
item SUBBOTIN, SERGEI - California Department Of Food And Agriculture
item FRAEDRICH, STEPHAN - Us Forest Service (FS)

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2016
Publication Date: 3/31/2016
Citation: Handoo, Z.A., Carta, L.K., Skantar, A.M., Subbotin, S.A., Fraedrich, S.S. 2016. Molecular and morphological characterization of a Xiphinema chambersi population from live oak trees in Jekyll Island, Georgia, with a redescription of the species and comments on its morphometric variations. Journal of Nematology. 48(1):20-27.

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that attack plant roots and cause billions of dollars of damage to forest and ornamental trees. One problem with determining the extent of nematode damage is that the nematodes present in many areas are not known, such as in Georgia. In this study, ARS scientists together with scientists from the California Department of Food and Agriculture and the U.S. Forest Service describe by both morphological and molecular means a species of economically important dagger nematode from soil around the roots of live oak trees in Jekyll Island, Georgia, USA. The results are significant because this discovery represents a new location of this nematode in Georgia. Because this report includes details necessary for scientists to correctly identify this species wherever it may occur, this research will be used by scientists, action agencies, and extension agencies engaged in nematode research and control.

Technical Abstract: A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, Georgia, USA 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, upon 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 2.1-2.5 mm; lip region slightly rounded and set off from head; total stylet length 170-193µm; vulva at 20.4%-21.8% of body length; a monodelphic, posterior reproductive system; elongate, conoid tail with a blunt terminus and 4 pairs of caudal pores, of which 2 pairs are subdorsal and 2 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 Xiphinema 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.