Location: Nematology Laboratory
2013 Annual Report
The colonization mechanisms of microorganisms called endophytes that live within plants are important in agricultural and natural resource management, because endophytes combat plant diseases and often change the toxin levels in some plants. These endophytic microorganisms may benefit or harm plants and livestock. Some nematodes also live endophytically within plant stems or roots, and certain species of nematodes can carry particular fungal or bacterial microorganisms within plants. Therefore identifying and characterizing these endophytic nematodes is important for managing plant diseases and the levels of toxins made by endophytic microorganisms. Scientists at the USDA in Beltsville demonstrated that nematodes isolated from stems of cheatgrass weeds had high-resolution microscopic head-views very similar to a much more commonly encountered species from soil. Another nematode from cultured roots of Idaho pine had a face pattern consistent with the few other species of that genus previously found only in soil. After further anatomical and molecular information is obtained, the discoveries will benefit farmers and rangeland managers who practice plant disease detection, therapy and prevention.
Identifying plant-parasitic nematodes through use of DNA molecular markers is important for accurate plant disease diagnosis. However, many species of anatomically described nematodes still have major gaps in their marker representation within genetic databases such as GenBank. Molecular sequences generated in the USDA Beltsville Nematology Laboratory for two plant-parasitic stunt nematode species are the first molecular markers for these types of nematodes. These new sequences will be used by plant disease diagnosticians.
Khan, M.R., Handoo, Z.A., Rao, U., Rao, S.B., Prasad, J.S. 2012. Observations on the foliar nematode, Aphelenchoides besseyi, infecting tuberose and rice in India. Journal of Nematology. 44(4):391-398. Hunt, D.J., Handoo, Z.A. 2012. Root-knot nematodes. In: Manzanilla-Lopez, R.H., Marban-Mendoza, N., editors. Practical Plant Nematology. Mexico City, Mexico: Mundi Prensa. p. 359-410. Baynes, M.A., Russell, D.M., Newcombe, G., Carta, L.K., Rossman, A.Y., Ismaiel, A.A. 2012. A mutualistic interaction between a fungivorous nematode and a fungus within the endophytic community of Bromus tectorum. Fungal Ecology. 5:610-623. Handoo, Z.A., Carta, L.K., Skantar, A.M., Chitwood, D.J. 2012. Description of Globodera ellingtonae n. sp. (Nematoda: Heteroderidae) from Oregon. Journal of Nematology. 44(1):40-57. Ibrahim, I.K.A., Awd-Allah, S.F.A., Handoo, Z.A. 2012. Host suitability of some Poaceous crop cultivars for Heterodera goldeni. Nematropica. 42(2):324-327. Mennan, S., Handoo, Z.A. 2012. Histopathology of Brassica oleracea var. capitata subvar. alba infected with Heterodera cruciferae Franklin, 1945 (Tylenchida: Heteroderidae). Turkish Journal of Entomology. 36(3):301-309. Yildiz, S., Handoo, Z.A., Carta, L.K., Skantar, A.M., Chitwood, D.J. 2012. The stunt nematode Sauertylenchus maximus in pastures of Bingol Province, Turkey. Igdir University Journal of the Institute of Science and Technology. 2(2):17-19. Yildiz, S., Handoo, Z.A., Carta, L.K., Skantar, A.M., Chitwood, D.J. 2012. A survey of plant-parasitic nematodes associated with forage crops in Bingol, Turkey. Nematologia Mediterranea. 40(1):73-77.