CONTROL OF PLANT-PARASITIC NEMATODES BY INTERFERENCE WITH INTERNAL TARGETS
Title: Extensive mitochondrial gene rearrangement in a genus of plant parasitic nematodes
| Gibson, Tracey - |
| Farrugia, Daniel - |
| Barrett, Jeff - |
| Rowe, Janet - |
| Subbotin, Sergei - |
| Dowton, Mark - |
Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 3, 2011
Publication Date: July 11, 2011
Citation: Gibson, T., Farrugia, D., Barrett, J., Chitwood, D.J., Rowe, J., Subbotin, S.A., Dowton, M. 2011. The mitochondrial genome of the soybean cyst nematode, Heterodera glycines. Genome. 54(7):565-574.
Interpretive Summary: Nematodes are microscopic worms that attack plant roots and annually cause ten billion dollars of crop losses in the United States. A major problem with reducing nematode-induced crop losses is that safe and effective control measures for nematodes are not available. One approach to developing new control methods is to disrupt unusual biochemical features of nematodes; the search for such features has previously revealed that potato cyst nematodes contain unusual features in the structure of a certain type of DNA called mitochondrial DNA. In this paper, an international team of scientists examined other species of nematodes, including other cyst nematodes, and discovered that they do not have the features unique to potato cyst nematodes. The results are significant because they indicate that potato cyst nematodes are unique among nematodes with respect to their mitochondrial DNA and that this feature has evolved relatively recently. Therefore, these results will be used by the many scientists investigating the evolution of nematodes, the biochemistry of nematode DNA, and the control of cyst nematodes.
The nematodes Globodera pallida and G. rostochiensis are two of the only animals known to have multipartite mitochondrial genomes. In such genomes, mitochondrial genes are distributed on multiple circles. The entire sequence of a nematode (Radopholus similis) that belongs to the same superfamily (Hoplolaimoidea) was recently reported, in which gene order is very different when compared with either G. pallida or G. rostochiensis. We sequenced multigenic fragments from the mitochondrial genomes of a range of heteroderid nematodes, in order to understand the evolutionary history of gene rearrangement. The entire coding region of the mitochondrial genome of Heterodera glycines was sequenced, while multigenic fragments from two other heteroderids, H. cardiolata ( H. cynodontis) and Punctodera chalcoensis, were also sequenced. Genome organization was very similar between the Heterodera and Punctodera species, but very different to that described in G. pallida and G. rostochiensis. Outgroup comparison, employing the pratylenchid R. similis, revealed that G. pallida and G. rostochiensis have an extremely derived genome organization, while all other heteroderids have an organization similar to R. similis. These data indicate that extensive mitochondrial gene rearrangement has occurred in the nematode genus Globodera. This may be a consequence of the multipartite structure of Globodera mitochondrial genomes, as subgenomic circles are formed by recombination between the circles.