ARS | Publication request: Transmission of potato purple top phytoplasma to potato tubers and daughter plants

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 2, 2011
Publication Date: July 18, 2011
Citation: Crosslin, J., Hamlin, L.L., Buchman, J., Munyaneza, J.E. 2011. Transmission of potato purple top phytoplasma to potato tubers and daughter plants. American Journal of Potato Research. 88:339-345.

Interpretive Summary: Phytoplasmas are bacteria-like pathogens that affect a number of important food crops around the world. In the Pacific Northwest, where approximately half of US potatoes are grown, a phytoplasma called the Columbia Basin potato purple top phytoplasma, has caused significant economic losses in the last several years. Although this pathogen is well known, there was relatively little information available on the rate of transmission of the phytoplasma to daughter potato tubers on an infected plant. In this study we showed that the phytoplasma was indeed transmitted at a relatively high rate to daughter tubers and subsequently to the plants grown from these tubers. This is the first study taking a detailed look at tuber transmission of this pathogen in numerous important varieties of potatoes grown in this region of the country. This information will be of significance to researchers, agricultural field inspectors, and the potato seed certification industry.

Technical Abstract: In 2006, 2007, and 2008, Alturas, Russet Burbank, FL1867, FL1879, Russet Norkotah, Ranger Russet, Shepody, and Umatilla Russet potatoes were planted at a research farm near Moxee, WA. Plants were allowed to become infested with native populations of the beet leafhopper which are known vectors of the Columbia Basin potato purple top phytoplasma, a member of phytoplasma group 16SrVI, in this region. Symptomatic plants were tested by PCR for the presence of the phytoplasma and positive plants were identified with flags. Tubers were harvested from positive plants and tested for the presence of phytoplasma. A subset of phytoplasma-positive tubers was planted in a greenhouse and the resulting daughter plants were tested for phytoplasma. The frequency of tuber transmission ranged from 4-96% among the eight cultivars over the three year period. Transmission of the phytoplasma from infected tubers to daughter plants ranged from 0-50% depending upon cultivar and year. Across the eight cultivars an average of 22%, 15%, and 16% of infected tubers gave rise to infected daughter plants in 2006-2008, respectively.