Wheat streak mosaic virus
| Wheat streak mosaic virus (WSMV) | |
|---|---|
| Virus classification | |
| Group: | Group IV ((+)ssRNA) |
| Family: | Potyviridae |
| Genus: | Tritimovirus |
| Species: | Wheat streak mosaic virus |
Wheat streak mosaic virus (WSMV) is a plant pathogenic virus of the family Potyviridae that infects plants in the Poaceae family, especially wheat (Triticum spp.); it is globally distributed and vectored by the wheat curl mite, particularly in regions where wheat is widely grown. First described in Nebraska in 1922, stunted growth and the eponymous “streaks” of yellowed, non-uniform discoloration are characteristic of WSMV infection. As it has been known to cause 100% crop mortality, WSMV is a subject of ongoing scientific research.
WSMV is a flexible, rod-shaped virus composed of a positive-sense single-strand RNA genome approximately 8.5 to 12 kilobases in length, and can be either mono- or bipartite. The RNA serves as both the genome and viral messenger. The genomic RNA (or its segments) is translated into polyprotein(s) which are transformed by virus-encoded proteases into functional products.
WSMV is semi-persistently transmitted by the wheat curl mite (Aceria tosichella), a small, cigar-shaped insect that can produce a single generation within 10 days under optimum temperature- approximately 27 °C. Wheat curl mites are slow crawlers, and depend on wind to disperse to other plants; they can also overwinter in abandoned infected wheat or corn heads. The mites also have the ability to transfer WSMV in between wheat and corn crops, allowing the virus to persist year-round. One of the most important management techniques to controlling WSMV is by eliminating “volunteer”, or seedlings from the previous years’ infected crop, wheat plants. WSMV often overwinters on the seeds, and can spread to a field planted after the infected seedlings have sprouted.
Depending on the location, WSMV infection has been reported to reduce yield by up to 100%; furthermore, WSMV has been shown to display synergistic interactions with other viruses (specifically Triticum mosaic virus and High plains virus), further exacerbating crop yield problems. WSMV infects some of the most agriculturally important members of the Poaceae family, including wheat, corn, rye, oats, barley, sorghum, and millet; additionally, some grassy weeds have been known to serve as alternate hosts.
“Serious infection of winter wheat occurs in early fall, but symptoms usually do not develop until spring. As spring temperatures rise, symptoms become more visible and rapidly develop when daily high temperatures first exceed about 80°F for several days.”
“Rolled and trapped leaves are good indicators of heavy mite populations, and their presence is useful in determining if stands of volunteer wheat are potential reservoirs of both the virus and the mite.”
“A cool spring will delay the onset of severe symptoms and moderate damage, but an early, warm spring will maximize impact on the plants.”
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Wikipedia