Analysis and functional classification of transcripts from the nematode Meloidogyne incognita.
BACKGROUND
Plant parasitic nematodes are major pathogens of most crops. Molecular characterization of these species as well as the development of new techniques for control can benefit from genomic approaches. As an entrée to characterizing plant parasitic nematode genomes, we analyzed 5,700 expressed sequence tags (ESTs) from second-stage larvae (L2) of the root-knot nematode Meloidogyne incognita.


RESULTS
From these, 1,625 EST clusters were formed and classified by function using the Gene Ontology (GO) hierarchy and the Kyoto KEGG database. L2 larvae, which represent the infective stage of the life cycle before plant invasion, express a diverse array of ligand-binding proteins and abundant cytoskeletal proteins. L2 are structurally similar to Caenorhabditis elegans dauer larva and the presence of transcripts encoding glyoxylate pathway enzymes in the M. incognita clusters suggests that root-knot nematode larvae metabolize lipid stores while in search of a host. Homology to other species was observed in 79% of translated cluster sequences, with the C. elegans genome providing more information than any other source. In addition to identifying putative nematode-specific and Tylenchida-specific genes, sequencing revealed previously uncharacterized horizontal gene transfer candidates in Meloidogyne with high identity to rhizobacterial genes including homologs of nodL acetyltransferase and novel cellulases.


CONCLUSIONS
With sequencing from plant parasitic nematodes accelerating, the approaches to transcript characterization described here can be applied to more extensive datasets and also provide a foundation for more complex genome analyses.
McCarter
James P
JP
Genome Sequencing Center, Department of Genetics, Box 8501, Washington University School of Medicine, St, Louis, MO 63108, USA. jmccarte@watson.wustl.edu
Mitreva
Makedonka Dautova
MD
Martin
John
J
Dante
Mike
M
Wylie
Todd
T
Rao
Uma
U
Pape
Deana
D
Bowers
Yvette
Y
Theising
Brenda
B
Murphy
Claire V
CV
Kloek
Andrew P
AP
Chiapelli
Brandi J
BJ
Clifton
Sandra W
SW
Bird
David Mck
DM
Waterston
Robert H
RH
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics; D002874:Chromosome Mapping; D016000:Cluster Analysis; D019295:Computational Biology; D020224:Expressed Sequence Tags; D022761:Gene Transfer, Horizontal; D017238:Genes, Helminth; D007814:Larva / Q000235:genetics; D010641:Phenotype; D034622:RNA Interference; D018510:RNA, Helminth / Q000032:analysis* / Q000145:classification* / Q000502:physiology; D017385:Sequence Homology; D014158:Transcription, Genetic; D017187:Tylenchida / Q000235:genetics; D014431:Tylenchoidea / Q000235:genetics* / Q000254:growth & development
D018510:RNA, Helminth