Sweetpotato mild mottle virus

The yield effects of this virus are unknown, but it can reduce the quality of vines for planting material.

Burundi, Kenya, Tanzania, Uganda, Philippines.

The predominant symptoms associated with SPMMV are mild leaf mottling and stunting. It induces distinct veinal chlorosis in Ipomea setosa.  None of these symptoms are diagnostic in the field and the virus can be latent.

SPMMV is transmitted non-persistently by the whitefly Bemisia tabaci. It is also perpetuated through planting infected cuttings. SPMMV is often found in sweetpotato plants also infected with sweetpotato feathery mottle virus (SPFMV) and sweetpotato chlorotic stunt virus (SPCSV) but whether there is any underlying link with either or both of these viruses is unclear.

SPMMV has been shown to spread in East Africa but no other epidemiological information is available.

SPMMV has been found naturally only in sweetpotato but can be transmitted experimentally to a wide range of plant species including many Ipomoea spp but also Beta vulgaris, Chenopodium murale, Datura stramonium, Gomphrena globosa, Lycopersicon esculentum, Nicotiana benthamiana, Petunia hybrida and Zinnia elegans.

Both monoclonal and polyclonal antisera have been developed against SPMMV allowing sensitive ELISA-based assays to be developed. The entire genome of SPMMV has been sequenced, allowing nucleic acid techniques to be utilised. The unusually wide host range and easy sap transmission of SPMMV allows transmission tests to be useful.

Sanitation and selection by farmers of symptomless planting material can help achieve control.

Some sweetpotato cultivars appear to be immune and others are tolerant.

References

Ames, T., Smit, N.E.J.M., Braun, A.R., O’Sullivan, J.N., and Skoglund, L.G. 1996. Sweetpotato: Major pests diseases, and nutritional disorders. International Potato Center (CIP). Lima, Perú. 152 p.

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). `Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 20^th August 1996.' URL http://biology.anu.edu.au/Groups/MES/vide/

Colinet, D., Kummert, J., Lepoivre, P. 1998. The nucleotide sequence and genome organisation of the whitefly-transmitted sweet potato mild mottle virus: a close relationship with members of the family Potyviridae. Virus Research 53:187-196.

Hollings, M. and Stone, O. M. 1976. Purification and properties of sweet potato mild mottle, a whitefly-borne virus from sweet potato (Ipomoea batatas) in East Africa. Annals of Applied Biology 82:511-528.

Contributed by:  Nicole Smit and Richard Gibson

Taxonomy

Economic importance

Geographical distribution

Symptoms

Biology and ecology

Host range

Detection and inspection

Management

References

Distinct yellowing of Ipomea setosa leaf veins due to SPMMV (J. Moyer, APS).