Rice stripe virus

Rice plants are susceptible to infection starting at the seedling age. The only known means of virus transmission is via planthoppers. Typical symptoms of rice stripe virus infection include pale and discontinuous yellow stripes, blotches, and dead tissue streaks on the leaves. Severe infections cause grey necrotic streaks and result in the death of the plant. If the plants grow, they produce few, if any, tillers and panicles with empty spikelets. Mature plants Infected mature plants do not have severe chlorosis or blotches, but ripening may be hindered. They can still produce rice, but with less vigor. ==Structure==

The virus is made up of four ssRNA segments, seven open reading frames, • RNA 1: This is the largest ssRNA segment with 8970 nucleotides. RNA 1 is negative sense and encodes a protein that is part of the RNA polymerase. • RNA 2 and RNA 4: These strands are ambisense. • RNA 3: Encodes for gene silencing suppressor proteins and nucleocapsid proteins. ==Epidemics==

This table from KnowledgeBank.irri.org summarizes reported epidemics of rice stripe virus. ==Prevention==

The lowland rice plants in Japan (japonica-type) are easily afflicted by rice stripe virus: however, upland japonica-type, indica-type, and Javanese varieties are resistant genetically. Hybrid varieties Chugoku 31 and St No1 were bred in Japan by crossing japonica-type cv. Norin No 8 with indica-type Modan. The offspring of this cross was then crossed with cv. Norin 8. Chugoku 31 and St No1 have been used to breed different varieties of rice stripe virus resistant rice plants in Japan. Since the 1950s, Japanese rice farmers have adopted the practice of planting rice early in the season. This allows the plants to grow past the tillering stage by the time planthoppers immigrate from wheat and barley plants. ==References==