The small brown planthopper (SBPH), Laodelphax striatellus, is a major insect pest for the rice plants. SBPH is also a known vector of rice stripe virus (RSV), which causes severe yield losses in rice crops throughout the East Asia. RSV is persistently transmitted by SBPH and can also be transmitted to offspring through transovarial transmission. SBPH is known to migrate from China to the west coast of the Republic of Korea (ROK). The study investigated the impact of temperature on the acquisition and transmission of RSV by SBPH in ROK, which is expected to experience increased migration and emergence of SBPH due to climate change. The results revealed that the acquisition and transmission rates of RSV were higher at 27°C compared to 24°C, with rates of 100% and 78.3%, respectively. However, at 30°C, the acquisition and transmission rates of RSV was decreased. The results suggests that temperature can impact the transmission of RSV by SBPH. To investigate this further, SBPH adults were fed on RSV-infected plants and infection rates were compared across various tissues, including the head, salivary glands, midgut, Malpighian tubules, ovary, and hindgut. Results showed that at 36 hours post-infection, RSV was highly detected in the Malpighian tubules, ovary, and hindgut. At 48 hours post-infection, RSV was also detected in the thorax. These results suggest that the transmission rates of RSV in SBPH increase with temperature between 24-27°C, but decrease at 30°C, indicating that the vectorial capacity of SBPH for RSV decreases above a certain threshold.

애멸구(Laodelphax striatellus)는 rice stripe virus (RSV)의 매개충으로 벼에 큰 피해를 주는 해충이다. 본 연구에서는 애멸구의 장·단시형, 암·수, 약·성충에 대한 RSV 보독률과 이병률을 비교하였다. 애멸구의 장·단시형의 RSV 보독률은 각각 60.7%, 63.1%로 크게 차이는 없었다. 암·수에 대한 RSV 보독률은 각각 61.9%, 52.2%로 암컷의 보독률이 더 높았으나 유의성은 없었다. 약·성충의 보독률을 비교한 결과 각각 51.2%, 58.7%로 역시 크게 차이가 나지는 않았다. RSV에 감염된 애멸구에 노출된 건전한 벼의 이병률은 장시형은 53.3%, 단시형은 48.2%를 보였으며, 약·성충의 이병률은 각각 38.2%, 42.6%를 보여 유의성은 없었다. 반면 암컷은 50.5%의 이병률을 보이고 수컷은 22.3%의 이병률을 보여 암컷이 수컷에 비해 22.3% 이병률이 높아 유의성이 있었다. 또한 벼와 애멸구의 RSV 감염여부에 의한 애멸구의 발육기간은 건전한 벼에 RSV 감염 애멸구를 접종 했을 때 가장 긴 것으로 나타났으며, 건전한 벼에 건전한 애멸구를 접종 했을 때 발육기간이 가장 짧은 것으로 나타났다.

Rice stripe disease, caused by rice stripe virus (RSV), is one of the major virus diseases in east Asia. The objective of this study was conducted to identify new resistance genetic source to rice stripe virus (RSV) disease. Genetic diversity of 155 rice cultivars was evaluated using 9 co-dominant InDel markers and STS marker ST10. These cultivars were classified into two groups by cluster analysis based on Nei`s genetic distances. The marker showed different band pattern among RSV resistance or susceptible cultivar. In comparison with bioassay for RSV resistance and genotyping using SSR markers showed that Stv-bi and InDel 7 marker observed recombination value within 3.8% and RSV resistance gene was closely related to InDel 7. Also InDel 7 divided as resistance type alleles and susceptible type alleles except for some varieties. Interestingly, 02428, Daw dam, Erguailai, Padi Adongdumarat, PERVOMAJSZKIJ, and Tung Ting Wan Hien 1 showed Japonica type in InDel 7 marker. However, these cultivars revealed resistant to RSV bioassay. These results indicate that those cultivar can be able to get the different gene resistance with Stv-bi gene. Newly identified resistance gene is considered useful for improving RSV resistance in japonica rice. Therefore, we will progress the allelism test and genetic analysis for identification of new gene source.

벼 바이러스병에 대한 최선의 방제책은 저항성 품종의 육성이라 할 수 있다. 저항성 품종의 육성을 위해서는 정밀하고 대량으로 검정 할 수 있는 검정법의 확립이 무엇보다 중요하므로 이를 위해 격리 검정망실을 건립 보독충을 방사한 후 이를 계대유지 하여 검정에 이용하였다. 망실내에 바이러스 보독충율 변이에서 연중 높은 보독충율을 유지하였으며, 매개충의 밀도도 검정에 충분하게 유지되었다. 망실을 이용한 바이러스병 저항성검정의 효율성은 줄무늬잎마름병은 92~100% , 오갈병은 100%의 검정효율을 보였으며, 이러한 대량검정법은 실내유묘검정과 고도의 정의 상관을 나타내어 포장검정의 대량검정과 실내유묘검정의 정밀도 등 장점을 겸비한 유용한 방법으로 확인되었다.