Meloidogyne hapla

Ecology

The northern Root-Knot-Nematode Meloidogyne hapla is a sedentary endoparasite, and only second-stage juveniles (the infective stage) and adult males (which may be rare) are present in soil. They are a major "disease" affecting many food crops worldwide causing an estimate damage of US$ 100 billion.

Biology

excerpt from "Sequence and genetic map of Meloidogyne hapla: A compact nematode genome for plant parasitism.", Opperman et al.

Many isolates of M. hapla reproduce by facultative meiotic parthenogenesis where sexual crosses occur, but, in the absence of males, the diploid state is restored by reuniting sister chromosomes of a single meiosis. With a 54 Mbp genome, M. hapla represents not only the smallest nematode genome yet completed, but also the smallest metazoan. The M. hapla genome encodes significantly fewer genes than does the free-living nematode Caenorhabditis elegans (most notably through a reduction of odorant receptors and other gene families), yet it has acquired horizontally from other kingdoms numerous genes suspected to be involved in adaptations to parasitism. In some cases, amplification and tandem duplication have occurred with genes suspected of being acquired horizontally and involved in parasitism of plants. Although M. hapla and C. elegans diverged >500 million years ago, many developmental and biochemical pathways, including those for dauer formation and RNAi, are conserved. Although overall genome organization is not conserved, there are areas of microsynteny that may suggest a primary biological function in nematodes for those genes in these areas.

Data on WormBase

• GBrowse
  • predicted gene models provided by NCSU
  • homologies and protein domains
  • orthologies to C.elegans
• DNA and Protein sequences
• GFF annotation

Ressources

• Centre for the Biology of Nematode Parasitism (NC State University) - original submitter of sequences and gene models [www.hapla.org]
• Plant Disease Control (Oregon State university)

Key Publications

• Opperman, et al. "Sequence and genetic map of Meloidogyne hapla: A compact nematode genome for plant parasitism.", Proc Natl Acad Sci U S A. 2008 Sep 30;105(39):14802-7. Epub 2008 Sep 22.