Rice stripe virus
| Rice stripe virus (RSV) | |
|---|---|
| Virus classification | |
| Group: | Group V ((−)ssRNA) |
| Order: | Bunyavirales |
| Family: | Phenuiviridae |
| Genus: | Tenuivirus |
| Species: | Rice stripe tenuivirus |
Rice stripe virus (RSV) is an RNA plant pathogen of the genus Tenuivirus.[1] RSV is prevalent in Japan, China, and Korea and can infect plants of the family Poaceae, which include wheat and corn (see maize stripe virus).[2] Damage from this disease causes major reductions in rice crop yield every year.[2]
It is spread primarily by Laodelphax striatellus, a small planthopper that feeds and damages rice plants by sap-sucking.[3] Three other planthopper insects that transmit RSV include Unkanodes sapporona, Unkanodoes albifascia, and Terthron albovittatum. The virus propagates in the planthopper and is passed down to 90% of a female's eggs.[4] However, mechanically transmitting the virus by injecting sap from an affected plant to a healthy plant has not been widely successful.[4]
Symptoms
Rice plants are susceptible to infection starting at the seedling age. The only known means of virus transmission is via planthoppers. Typical symptoms of RSV include pale and discontinuous yellow stripes, blotches, and dead tissue streaks on the leaves.[5] Severe infections cause grey necrotic streaks and result in the death of the plant.[6]
Young plants
Infection causes the most damage during seedling stage to maximum tillering stage[7] because during this time interval, the plants are at a higher risk of death.[5] Affected seedlings are stunted in growth with leaves that elongate without unfolding. Their color pales to white with drooped, curled, dead leaves. In Japan, this disease was called "Yurei Byo" (ghost disease) because of these symptoms.[7] 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.[5]
Structure
The virus is made up of four ssRNA segments, seven open reading frames,[2] a nucleocapsid protein, and an RNA polymerase protein. It is 8 nm in diameter[1] and 500-2000 nm long.[6]
- RNA 1: This is the largest ssRNA segment with 8970 nucleotides.[4] 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.[2]
Epidemics
This table from KnowledgeBank.irri.org summarizes reported epidemics of RSV.[5]
| Year | Country | Area Affected (ha) | Reference |
|---|---|---|---|
| 1960s | Japan | 500,000 | Maeda et al. (2006) |
| 1960s | Eastern and Southern China | 2,660,000 | Wang et al. (2008) |
| 1963-67 | Japan | 500,000 to 620,000 annually | Nemoto et al. (1994) |
| 1973 | Japan | 620,000 | Ou (1985) |
| 1973 | Taiwan | 1,045 | Lee (1975) |
| 1986 | Japan | 170,000 | Nemoto et al. (1994) |
| Not indicated | Yunnan Province, China | 67,000 | Wang et al. (2008) |
| 2002 | Jiangsu Province, China | 780,000 | Wei et al. (2009) |
| 2003 | Jiangsu Province, China | 957,000 | Wei et al. (2009) |
| 2004 | Jiangsu Province, China | 1,571,000 | Wei et al. (2009) |
| 2005-06 | Zhejiang Province, China | 100,000 | Wang et al. (2008) |
| 2007 | Zhejiang Province, China | 17,600 | Zhu et al. (2009) |
| 2007-08 | Korea | 84% of rice fields | Jonson et al. (2009) |
Prevention
The lowland rice plants in Japan (japonica-type) are easily afflicted by RSV, 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 offpring of this cross was then crossed with cv. Norin 8. Chugoku 31 and St No1 have been used to breed different varieties of RSV 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.[5]
References
Bibliography
- Castilla, NP; S. Savary; A. Sparks; IR Choi (2009). "Rice Stripe". International Rice Research Institute. Archived from the original on 15 April 2013. Retrieved 25 January 2013.
- Gingery, Roy; Lowell Nault; Shuichi Yamashita (23 March 1983). "Relationship Between Maize Stripe Virus and Rice Stripe Virus". Journal of General Virology. 64: 1765–1770. doi:10.1099/0022-1317-64-8-1765.
- "Rice Stripe Tenuvirus (Rice Stripe Virus)". Plantwise. Archived from the original on 15 April 2013. Retrieved 20 February 2013.
- "Rice Stripe Virus". Rothamsted Research. June 2000. Retrieved 25 January 2013.
- Toriyama, Shigemitsu; Mami Takahashi; Yoshitaka Sano; Takumi Shimizu; Akira Ishihama (1994). "Nucleotide sequence of RNA 1, the largest genomic segment of rice stripe virus, the prototype of the tenuiviruses". Journal of General Virology. 75: 3569–3579. doi:10.1099/0022-1317-75-12-3569.
- Wei, Tai-Yun; Jin-Guang Yang; Fu-Long Liao; Fang-Luan Gao; Lian-Ming Lu; Xiao-Ting Zhang; Fan Li; Zu-Jian Wu; Qi-Yin Lin; Lian-Hui Xie; Han-Xin Lin (29 December 2008). "Genetic diversity and population structure of rice stripe virus in China" (PDF). Journal of General Virology. 90: 1025–1034. doi:10.1099/vir.0.006858-0. Retrieved 4 February 2013.
- Xiong, Ruyi; Jianxiang Wu; Yijun Zhou; Xueping Zhou (2008). "Identification of a Movement Protein of the Tenuvirus Rice Stripe Virus" (PDF). Journal of Virology. 82 (24): 12304–2311. doi:10.1128/jvi.01696-08. Retrieved 25 January 2013.
- Zhang, Fugie; Hongyan Guo; Tong Zhou; Yijun Zhou; Shengyue Wang (13 May 2010). "Massively Parallel Pyrosequencing-based Transcriptome Analyses of Small Brown Planthopper (Laodelphax Striatellus), a Vector Insect Transmitting Rice Stripe Virus (RSV)" (PDF). BMC Genomics. Retrieved 25 January 2013.