Monoclonal Antibody-Based Serological Detection of Rice Stripe Mosaic Virus Infection in Rice Plants or Leafhoppers

Rice stripe mosaic virus(RSMV) is a rhabdovirus recently found in southern part of China and can cause severe reduction in rice production. To establish serological methods for RSMV epidemiological studies and to establish a control strategy for this virus, we first purified RSMV virions from infected rice plants and then used them as an immunogen to produce four RSMV-specific monoclonal antibodies(MAbs)(i.e.,1D4, 4A8, 8E4 and 11F11). With these MAbs, we have developed a highly specific and sensitive antigen-coated plate enzyme-linked immunosorbent assay(ACP-ELISA), a Dot-ELISA and a Tissue print-ELISA for rapid detections of RSMV infection in rice plants or in leafhoppers. Our results showed that RSMV can be readily detected in RSMV-infected rice plant tissue crude extracts diluted at 1:20,971,520(w/v, g/m L)through ACP-ELISA or diluted at 1:327,680(w/v, g/m L) through Dot-ELISA. Both ACP-ELISA and Dot-ELISA can also be used to detect RSMV infection in individual RSMV viruliferous leafhopper(Recilia dorsalis) homogenate diluted at 1:307,200 and 1:163,840(individual leafhopper/l L), respectively. Detection of RSMV infection in field-collected rice samples or in RSMV viruliferous leafhoppers indicated that the three serological methods can produce same results with that produced by RT-PCR(19 of the 33 rice samples and 5 of the 16 leafhoppers were RSMV-positive). We consider that the four MAbs produced in this study are very specific and sensitive, and the three new serological methods are very useful for detections of RSMV infection in rice plants or in leafhoppers and the establishment of the disease control strategies.

Polyamine-metabolizing enzymes are activated to promote the proper assembly of rice stripe mosaic virus in insect vectors

Both viruses and host cells compete for intracellular polyamines for efficient propagation.Currently,how the key polyamine-metabolizing enzymes,including ornithine decarboxylase 1(ODC1)and its antizyme 1(OAZ1),are activated to co-ordinate viral propagation and polyamine biosynthesis remains unknown.Here,we report that the matrix protein of rice stripe mosaic virus(RSMV),a cytorhabdovirus,directly hijacks OAZ1 to ensure the proper assembly of rigid bacilliform non-enveloped virions in leafhopper vector.Viral matrix protein effectively competes with ODC1 to bind to OAZ1,and thus,the ability of OAZ1 to target and mediate the degradation of ODC1 is significantly inhibited during viral propagation,which finally promotes polyamines production.Thus,OAZ1 and ODC1 are activated to synergistically promote viral persistent propagation and polyamine biosynthesis in viruliferous vectors.Our data suggest that it is a novel mechanism for rhabdovirus to exploit OAZ1 for facilitating viral assembly.

我国粮食作物病毒病发生与防控现状

近年来,我国水稻、小麦、玉米病毒病发生严重,造成重大经济损失。本文就近年来水稻、小麦和玉米等主要粮食作物上水稻条纹叶枯病、水稻黑条矮缩病、南方水稻黑条矮缩病、小麦黄花叶病以及玉米粗缩病的发生现状、防控情况,以及防控过程中存在的问题作简要概述,并展望下一阶段防控任务。

水稻条纹花叶病毒对介体电光叶蝉生长繁殖及取食行为的影响

【目的】由电光叶蝉Recilia dorsalis传播的水稻条纹花叶病毒(rice stripe mosaic virus,RSMV)目前在我国华南稻区大面积发生并对水稻生产造成严重危害。本研究旨在明确RSMV对介体电光叶蝉生长繁殖及取食行为的影响。【方法】通过生物学实验测定RSMV侵染后电光叶蝉的生长和生命表参数;利用刺吸电位(electrical penetration graph,EPG)技术比较携带和未携带RSMV的电光叶蝉成虫在健康水稻上的取食行为差异;采用Y型嗅觉仪测定电光叶蝉成虫对感染和未感染RSMV水稻的寄主选择倾向性。【结果】与无毒电光叶蝉相比,携带RSMV的电光叶蝉若虫发育历期延长,而若虫存活率、成虫羽化率、雌虫繁殖力和卵孵化率下降。无毒电光叶蝉成虫倾向于选择取食RSMV侵染的水稻,而带毒电光叶蝉成虫倾向于选择取食健康水稻。与无毒电光叶蝉相比,带毒电光叶蝉成虫取食健康水稻所产生的刺探波、障碍波和唾液分泌波次数和持续时间均显著增加,被动取食波和休息波次数减少但时间均延长。【结论】与无毒电光叶蝉相比,感染RSMV使带毒电光叶蝉若虫发育历期延长且不利于其种群的繁殖。RSMV通过调控介体电光叶蝉成虫的取食和寄主选择行为而有利于自身在寄主水稻间的传播。

水稻条纹花叶病毒侵染水稻引起的细胞病理学变化研究

水稻条纹花叶病毒(RSMV)是近年在广东省发现的一种新的细胞质弹状病毒,对水稻生产有严重危害。用携带RSMV的电光叶蝉取食水稻幼苗,获得RSMV侵染的植株。被感染幼苗发育迟缓,叶片有黄色花叶。对病叶超微结构观察发现,病毒粒子首尾相连并集聚成晶状结构分布于细胞质中。细胞质中含有纤维状病毒基质,病毒在其中生成,部分排列成聚集体。成熟病毒粒子由内质网膜芽生,并聚集在扩大的内质网池中,还有病毒分布在核周腔中。部分叶绿体片层结构疏松并瓦解。此外,在叶片表皮细胞和维管束细胞中也发现RSMV侵染的细胞病理学特征。本研究在细胞病理学上证明RSMV对水稻的发育有严重危害。

水稻条纹花叶病田间调查及分子检测

水稻条纹花叶病(Rice stripe mosaic disease)是近年在华南地区新发现的水稻病毒病。该病由电光叶蝉(Recilia dorsalis)以持久增殖型方式传播。2017年至2018年,连续两年的调查结果表明,该病害广泛分布于华南稻区,以广东西南和广西东南部发生较重。室内人工接种和田间病株观察揭示,该病的症状主要表现为病株轻度矮化,叶片呈淡黄色条纹或花叶,重病株叶片基部扭转畸形,抽穗不完全,籽粒不饱满。根据病毒复制酶(L)基因设计一对特异引物(RSMV-L-F:5′-CTCCAACTATCATCCGCTATGC-3′;RSMV-L-R:5′-CCATCCGAGATAAGGTCACTGT-3′),经RT-PCR可对水稻病株及叶蝉体内的病原病毒进行快速、准确的检测。