|Van Der Beek, J|
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2003
Publication Date: 3/1/2004
Citation: Handoo, Z.A., Nyczepir, A.P., Esmenjaud, A.P., Van Der Beek, J.G., Castagnone-Sereno, P., Carta, L.K., Skantar, A.M., Higgins, J.A. 2004. Morphological and molecular characterization of meloidogyne floridae n. sp. (nematoda: meloidogynidae), a root-knot nematode parasitizing peach in florida. Journal of Nematology. 36(1):20-35. Interpretive Summary: Nematodes are microscopic worms that cause ten billion dollars of crop losses in the United States each year. Root-knot nematodes are very important root parasites that seriously damage many economic and other plants worldwide. A specific problem with peach production in the southeastern United States is the occurrence of a type of root-knot nematode that can attack peach roots that previously were believed to be resistant to all root-knot nematodes. In the present study, a collaboration of ARS scientists from Byron, Georgia and Beltsville, Maryland, together with researchers from France and the Netherlands, discover the methods for being able to distinguish this nematode from other root-knot nematodes. The investigators used anatomical, host-range, cellular, DNA sequence, and other molecular data to describe and illustrate this new root-knot nematode species. Both light and high-powered scanning electron microscope observations indicated that the species is closely related to three other nematode species in the United States and one in Spain. Photographs and measurements are provided for easier identification by other scientists. Host-range tests revealed that this nematode attacks tomato, watermelon, and the newly released Guardian peach rootstock; cotton was a poor host; and tobacco, green pepper and peanut were nonhosts. The results are significant because they provide the molecular and anatomical details necessary for scientists to identify this species wherever it may occur in the world. This research will be used by scientists, action agencies, and extension agencies engaged in nematode research and control.
Technical Abstract: A root-knot nematode, Meloidogyne floridae n. sp., is described and photographed from peach (Prunus persica (L.) Batsch) roots from Gainesville, Florida. It is characterized by: having a distinctive perineal pattern with a high to narrowly rounded arch, coarse broken and network like striae in and around anal area, faint lateral lines interrupting transverse striae, a sunken vulva and anus and large distinct phasmids; female stylet 13-16um long with rounded, broad to posteriorly sloping knobs with cone being distinctly dorsally straight, pointed. Second-stage juvenile body length 355(310-390um), tail length 39(35-42um) with a broad to bluntly rounded terminus. Males with both short and long forms 1,162(564-1,742um), stylet length 20(17-23um), spicule length 28 (23-35um). Scanning electron microscope provided further details of the perineal pattern and details of the head of females, males and second-stage juveniles. Its relationship to M. incognita, M. christiei and M. graminicola and M. hispanica is discussed. In greenhouse tests, the newly released Guardian peach rootstock, tomato and watermelon were good hosts; cotton was a poor host; tobacco, pepper and peanut were nonhosts. M. floridae n. sp. reproduces by meiotic parthenogenesis and/or amphimixis and the haploid chromosome number is n = 18, and possibly sometimes 19 or 20. Esterase phenotype results yielded atypical enzymatic pattern vs. the four common root-knot nematodes (Mi, Ma, Mh, Mj).