Friday, April 8, 2016

Distribution and diversity of a potato cyst nematode

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Potato cyst nematodes (PCN) are small (1 mm) roundworms belonging to the genus Globodera, which comprises 12 species. These worms live on the roots of plants of the Solanaceae family with prominent members such as potatoes and tomatoes. The nematodes cause growth retardation and, at very high population densities, damage to the roots and early senescence of the plants. PCN are thought to be originated in the Andes but are now widespread both in Europe and North America .

These nematodes can cause significant economic damage. Estimated costs due to yield loss and control measures are thought be at the range of billions of US dollars. PCN species are present on both EPPO and USDA quarantine organism lists.

Science and Advice for Scottish Agriculture (SASA) annually undertake national DNA diagnostic tests to determine the presence of PCN in potato seed and ware land by extracting DNA from soil floats. These DNA samples provide a unique resource for monitoring the distribution of PCN and further interrogation of the diversity within species.

In a new study researchers identified a section of cytb (<450bp) descriptive of three main mitotypes of one species (Globodera pallida) present in the UK and used a high throughput sequencing approach to the simultaneous analysis of all SASA samples (>800). By using this approach, the colleagues were able to describe the distribution of Globodera pallida mitotypes across Scotland with field-scale resolution. In addition they could quantify the relative abundance of each mitotype across an order of magnitude.

This study provides a method for accurate, quantitative and high-throughput typing of up to one thousand fields simultaneously, while revealing novel insights into the national genetic variability of an economically important plant parasite.

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