Nematode Parasitism Genes.
The ability of nematodes to live on plant hosts involves multiple parasitism genes. The most pronounced morphological adaptations of nematodes for plant parasitism include a hollow, protrusible stylet (feeding spear) connected to three enlarged esophageal gland cells that express products that are secreted into plant tissues through the stylet. Reverse genetic and expressed sequence tag (EST) approaches are being used to discover the parasitism genes expressed in nematode esophageal gland cells. Some genes cloned from root-knot (Meloidogyne spp.) and cyst (Heterodera and Globodera spp.) nematodes have homologues reported in genomic analyses of Caenorhabditis elegans and animal-parasitic nematodes. To date, however, the candidate parasitism genes endogenous to the esophageal glands of plant nematodes (such as the ß-1,4-endoglucanases) have their greatest similarity to microbial genes, prompting speculation that genes for plant parasitism by nematodes may have been acquired by horizontal gene transfer.
Davis
Eric L
EL
Department of Plant Pathology, North Carolina State University, Campus Box 7616, Raleigh, North Carolina 27695; e-mail: eric_davis@ncsu.edu.
Hussey
Richard S
RS
Department of Plant Pathology, University of Georgia, 2309 Miller Plant Science Building, Athens, Georgia 30602-7274; e-mail: hussey@uga.cc.uga.edu.
Baum
Thomas J
TJ
Department of Plant Pathology, Iowa State University, 351 Bessey Hall, Ames, Iowa 50011; e-mail: tbaum@iastate.edu.
Bakker
Jaap
J
Department of Nematology, Wageningen University and Research Centre, Binnenhaven 10, PD Wageningen, 6709 The Netherlands; e-mail: Jaap.Bakker@MEDEW.NEMA.WAU.NL ; Arjen.Schots@LMA.NEMA.WAU.NL.
Schots
Arjen
A
Department of Nematology, Wageningen University and Research Centre, Binnenhaven 10, PD Wageningen, 6709 The Netherlands; e-mail: Jaap.Bakker@MEDEW.NEMA.WAU.NL ; Arjen.Schots@LMA.NEMA.WAU.NL.
Rosso
Marie-Noëlle
MN
Laboratoire de Biologie des Invertebres, Institut National de la Recherche Agronomique, 123 Boulevarde Francis Meilland, Cedex Antibes, 06600 France; e-mail: rosso@antibes.inra.fr ; abad@antibes.inra.fr.
Abad
Pierre
P
Laboratoire de Biologie des Invertebres, Institut National de la Recherche Agronomique, 123 Boulevarde Francis Meilland, Cedex Antibes, 06600 France; e-mail: rosso@antibes.inra.fr ; abad@antibes.inra.fr.