Crop Genebank Knowledge Base

Articles

Phytoplasma - potato

Contributors to this section: CIP, Lima, Peru (Carols Chuquillanqui, Segundo Fuentes, Ivan Manrique, Giovanna Muller, Willmer Pérez, Reinhard Simon, David Tay, Liliam Gutarra); CIP, Nairobi, Kenya (Ian Barker); FERA, UK (Derek Tomlinson, Julian Smith, David Galsworthy, James Woodhall).

Potato purple-top wilt phytoplasma

Scientific name

Potato purple-top wilt

Six phytoplasmas on potato has been distinguished:

Potato witches' broom phytoplasma
Potato marginal flavescence phytoplasma
Potato purple toproll phytoplasma
Potato phyllody phytoplasma
Potato stolbur phytoplasma
Potato purple-top wilt phytoplasma

Significance

Potato purple-top wilt phytoplasma is EPPO A1 quarantine organism.

Hosts

Potato purple-top wilt phytoplasma is closely related to the aster yellows phytoplasma complex which has a very wide host range. About 350 species from at least 54 plant families are susceptible. Potatoes are not favored hosts (Wright et al., 1983). It is difficult to state categorically what is the host range of the phytoplasmas of this group found in potato.

Geographic distribution

North America (Lee et al., 2006)
Europe (Russia)(Girsova et al., 2008)

Biology and transmission

The principal vector is the leafhopper Macrosteles fascifrons, in which the phytoplasmas are propagative. The vectors remain infective for life. They can
feed on a variety of plants, and the apparent host range of the phytoplasma depends more on the host preferences of the vector than on any particular specificity between plant and phytoplasma.

Detection/indexing method in place at CIP

At CIP, detection methodology is being improved

Treatment/control

In seed certification schemes, no virus infections must be tolerated during the growing season. Stocks of in vitro cultures used for propagation should be from pathogen-free plants and maintained under conditions designed to prevent infection and contamination.

Procedure followed at the centers in case of positive test

In CIP if pathogen is detected the imported germplasm must be cleaned by thermotherapy.

References of protocols at EPPO, NAPPO or other similar organization

CABI/EPPO. Data sheets on Quarantine pest: Potato purple-top wilt phytoplasma. Prepared by CABI and EPPO for the European Communities. 5 p.

References and further reading

Girsova N, Bottner KD, Mozhaeva KA, Kastalyeva TB, Owens RA, Lee I. 2008. Identification of Phytoplasma Species Associated With Potato Diseases in Russia. International Symposium on Crop Protection. 73 (2): 331–333.

Lee IM, Bottner KD, Secor G, Rivera-Varas V. 2006. "Candidatus Phytoplasma americanum", a phytoplasma associated with a potato purple top wilt disease complex. Int. J. Syst. Evol. Microbiol. 56 (7):1593–1597.

Wright NS, Raine J, Valenta V. 1983. Mycoplasmas. In: Compendium of potato diseases (Ed. by Hooker, W.J.), pp. 91–93. American Phytopathological Society, St. Paul, Minnesota, USA.

Younkin SG. 1943. Purple-top wilt of potatoes caused by the aster yellows virus. American Journal of Potato Research 20 (7):177–183.

Seed Health General Publication Published by the Center or CGIAR

Jeffries C. 1998. FAO/IPGRI Technical guidelines for the safe movement of Germplasm. No. 19. Potato. Food and Agriculture Organization of the United Nations, Rome/International Plant Genetic Resources Institute, Rome.