Sweet potato feathery mottle virus (SPFMV) is a member of the genus Potyvirus in the family Potyviridae.

It is most widely recognized as one of the most regularly occurring causal agents of sweet potato viral disease (SPVD) and is currently observed in every continent except Antarctica.

[3] SPFMV was initially discovered in the United States 70 years ago, and currently, it is the most widely spread sweet potato virus in the world.

The encoded genes are P1, HC-Pro (helper component proteinase), P3, 6K1, CI, 6K2, NIa, NIb, and the coat protein cistron, which is found in a variety of other viruses.

After entry, helper component proteinase (HcPro) binds eIF4E, a eukaryotic cap-binding translation initiation factor that plays a crucial role for potyvirus replication.

One such method is the creation of transgene plants using proteins such as cysteine proteinase inhibitors, which would inhibit viral polyprotein cleavage.

[1] The disease's widespread dominance is conducive to high levels of variance between isolates, as many are separated by significant geographical distance and develop unique mutations.

[18] Variance between strains is due to sequence differentiation in the coat protein gene, occasionally leading to a different immune response.

[19] It is speculated that HC-Pro activity, which is involved in the long-distance movement of SPFMV, is one of the primary mechanisms by which all these viruses are propagated throughout the plant.

[16] Since most plant viruses exhibit mild, localized effects and generally go either undetected or untreated, the symptoms involved in co-infections such as SPVD are a unique threat.

[20] SPVD spreads rapidly and has a host of symptoms, but usually manifests itself in stunted plant growth and leaves exhibiting pale coloration, mosaic patterns, abnormal smallness or narrowness, distortion or crinkling.

In Oceana, for example, co-infections involving SPFMV have been observed to be less virulent, while those in Southern Africa display more damage and significant yield loss in crops.

[3] The virus especially impacts impoverished families and those living far from cities, demographics that rely more heavily on the sweet potato for food.