大湄公河次区域稻飞虱传病毒病的毒源及传播路径研究

Rice planthoppers (RPH)-transmitted Virus diseases constitute serious threat to rice production and global food security. Recently，the most effective control strategy is to reduce the pest population and disease occurence in source areas and cut the migration routes of RPH and related viruses. Many evidences showed the Greater Mekong Subregion (GMS) countries including Cambodia, Laos, Myanmar, Thailand and Vietnam are main oversea source areas of immigration RPH in rice grown regions of south China. However, little is known about geographic origin and migration routes of RPH and related rice viruses, and source-sink correlation between disease outbreak in China and oversea virus sources in the GMS countries. On base of the previous cooperation projects between Yunnan and the GMS countries, multi-point survey of field will be conducted to collect the rice and RPH samples from the GMS countries and Yunnan province. The virus species from rice and RPH samples will be identified. The population structure and genetic evolution mechanism of RPH-vectored viruses will be analysis. The species and genetic diversities of viruses in the immigratory RPH during the migration peak period will be identified and analyzed to uncover the geographic origin and migration routes of RPH and related viruses, and source-sink correlation mechanism of rice virus diseases in the GMS. These results will provide insight into migrations of RPH and related viruses in the GMS countries, and aid in oversea monitoring and warning outbreak of rice virus diseases in China, and should also form a basis for sustainable management of the economically important pest insect and virus diseases in this region.

迁飞性害虫稻飞虱传播的病毒病严重威胁到水稻生产和世界粮食安全。源头治理和切断传播路径是有效的控制策略。我国南方稻区稻飞虱虫源主要从境外大湄公河次区域（简称GMS）柬埔寨、老挝、缅甸、泰国、越南等国迁入。然而，目前我国稻飞虱传病毒病的境外毒源种类、地理来源，以及各发病区之间的源库关系，尚不清晰。本项目拟在前期与GMS国家合作项目的基础上，通过境外多点调查采样，开展GMS国家以及我国云南稻飞虱传播的重要病毒种类鉴定；研究GMS稻区稻飞虱传播的重要病毒种群结构、遗传进化机制；研究主迁峰期稻飞虱体内携带病毒种类、遗传结构差异，揭示区域内稻飞虱及其传水稻病毒的地理来源和传播路径，明确GMS稻区水稻重要病毒病源库关联机制，为我国稻飞虱传播的水稻病毒病境外监测预警、源头治理提供理论依据和技术支撑。

稻飞虱传播的水稻病毒是水稻安全生产的严重威胁，云南是境外GMS国家稻飞虱迁入我国的重要路径之一，明确云南稻飞虱及其传播病毒与GMS的柬埔寨、老挝、缅甸、泰国、越南等国家的库源关联将为监测境外稻飞虱的入迁提供理论依据。研究表明云南及GMS国家的近年（2018-2021）稻飞虱及其传播的水稻病毒动态：稻飞虱发生面积大，但种群小，百株虫量低（平均<10头），且携带水稻病毒（SRBSDV、RRSV）带毒率较低（<0.1%），仅从云南稻飞虱中检测到SRBSDV、RRSV，境外样品未检测到；白背飞虱是云南稻飞虱主要种群。稻飞虱携带的共生病毒种类多样性丰富，发现30个病毒科，包括212种病毒，其中新病毒种类近120种，主要属于传染性软化症病毒科、全病毒、类南方菜豆花叶病毒目、帚状病毒科、弹状病毒科、呼肠孤病毒科以及褐飞虱裸杆状病毒、无脊椎动物彩虹病毒等，为研究稻飞虱传播的水稻病毒的起源、遗传进化提供了数据。检测到的SRBSDV、RRSV遗传变异小。稻飞虱携带共生病毒遗传多样性丰富，具有稻飞虱种的专性特征和地理区域特征。关联分析稻飞虱携带的类南方菜豆花叶病毒目的Sobemo-like病毒种类与地理区域的关系，初步发现该类病毒可以用作稻飞虱及其传播的水稻病毒的毒源及传播路径预测依据，预测结果与用气象轨迹、线粒体基因标记预测的稻飞虱及其传播病毒的毒源及路径较一致：云南广南白背飞虱主要来源于缅甸、越南北部，勐海来源老挝、缅甸，云南元江、寻甸来源缅甸；云南元江、寻甸褐飞虱主要起源于柬埔寨经泰国、越南入境。近年境外稻飞虱没有检测到水稻病毒，田间无感病植株，这也是近年虽然有大规模稻飞虱种群入迁，但没有发生稻飞虱传播的水稻病毒暴发的原因之一。所以近年入境稻飞虱传播的重要病毒病在云南发生流行的可能性较低。本研究为云南地区稻飞虱传播病毒境外源头的异地监测、预警提供了理论依据。