利用小RNA高通量测序技术检测玉米病毒

正玉米是我国重要的粮食作物,种植范围日趋增大,病害的发生对玉米造成极大为害,病毒病对玉米稳产高产已构成严重威胁。近年来,安徽、山东和辽宁玉米主要种植区病毒病危害较重。为了检测发病玉米的病毒种类,本研究利用小RNA高通量测序技术鉴定玉米病毒,明确种类,以期为制定抗病毒策略提供理论依据。据不完全统计,世界上有40多种玉米病毒病(http://en.wikipedia.org),在我国发生并报道的有5种,分别为玉米粗缩病、玉米矮花叶病、玉米条纹矮缩病、玉米红叶病和玉     

浙江省水稻病毒病的发生规律和防治

 本文总结了1965-1977年水稻病毒病主要是黑条矮缩病、普通矮缩病的发生规律和传毒昆虫传病特点等方面的调查研究工作。
水稻黑条矮缩病由灰稻虱传播。灰稻虱能把病毒自水稻传到水稻、大小麦、玉米,但难以把病毒从玉米传到其它寄主上。已证实田间早熟禾可以作为黑条矮缩病无症带毒寄主。     

玉米粗缩病的病毒寄主范围研究

 作者在1980~1981年,通过灰飞虱(Laodelphax Striatellus Fallen)接种,试测了36属70种禾本科植物和棉花等9种双子叶植物。根据病状和回接结果,57种禾本科植物感染,所试双子叶植物均不感染。     

陕西玉米病毒病及流行因素研究

 研究结果表明:陕西玉米病毒病毒原主要有玉米矮花叶病毒B株系(MDMV-B)、玉米粗缩病毒(MRDV)和大麦黄矮病毒(BYDV)。用血清鉴定225份病株样品中,MDMV-B、MRDV和BYDV侵染分别占40%、23%、4.5%。MDMV-B和MRDV复合侵染占23.5%。在田间自然条件下,MDMV-B主要通过玉米蚜和禾谷缢管蚜以非持久性传播,MRDV则由灰飞虱以持久传播。MDMV-B、MRDV和BYDV的粒子大小分别为735~755 nm×17 nm、70~75 nm和23~30 nm。随着玉米生育成熟,侵染逐渐降低,为害亦趋减轻。研究认为,玉米品种、播种期、播量、田间传毒介体数量及发生早晚和地膜覆盖等是影响玉米病毒病流行的主要因素。     

Enzyme-linked immunosorbent assays for study of serological relationships and detection of three luteoviruses

Enzyme-linked immunosorbent assay (ELISA) systems were used to examine serological relationships and to detect three luteoviruses; a vector-non-specific strain of barley yellow dwarf virus from Illinois (BYDV-PAV-IL), a strain of beet western yellows virus from California (BWYV-CA) and a dwarfing strain of soybean dwarf virus from Japan (SDV-D). Indirect ELISA (IND-ELISA) systems detected distant reciprocal serological relationships among all three viruses. This is the first report of a serological relationship between a vector-non-specific strain of BYDV and any strain of SDV. Double antibody sandwich ELISA (DAS-ELISA) systems detected the purified homologous viruses at concentrations as low as 1.6 ng/ml. hut did not detect heterologous viruses as concentrated as 800 ng/ml. In contrast, when DAS-ELISA systems were used for detection of the three viruses in sap extracts from infected plants some weak but significant (P=0.05 ) heterologous reactions occurred. The BYDV-PAV-IL DAS-ELISA system usually detected BWYV-CA and sometimes detected SDV-D; the BWYV-CA DAS-ELISA system never detected BYDV-PAV-IL and rarely detected SDV-D; the SDV-D DAS-ELISA system sometimes detected BYDV-PAV-IL and consistently detected BWYV-CA.     

Reservoirs of plant virus disease: Occurrence of wheat dwarf virus and barley/cereal yellow dwarf viruses in Sweden

Non-crop plants such as grasses and volunteer plants are an inseparable part of the flora of crop fields and can influence virus incidence in crop plants. The presence of grasses as virus reservoirs can lead to a higher probability of virus incidence in crop plants. However, the role of reservoirs as an inoculum source in agricultural fields has not been well studied for many viral diseases of crops. Grasses have been found to constitute potential reservoirs for cereal-infecting viruses in different parts of the world. This study revealed that cereal-infecting viruses such as wheat dwarf virus (WDV), barley yellow dwarf viruses (BYDVs), and cereal yellow dwarf virus-RPV (CYDV-RPV) can be found among ryegrass growing in or around winter wheat fields. Phylogenetic analysis showed that a WDV isolate from ryegrass was a typical WDV-E isolate that infects wheat. Similarly, a ryegrass isolate of barley yellow dwarf virus-PAV (BYDV-PAV) grouped in a clade together with other BYDV-PAV isolates. Inoculation experiments under greenhouse conditions confirmed that annual ryegrass of various genotypes can be infected with WDV to a very low titre. Moreover, leafhoppers were able to acquire WDV from infected ryegrass plants, despite the low titre, and transmit the virus to wheat, resulting in symptoms. Information from the grass reservoir may contribute to improving strategies for controlling plant virus outbreaks in the field. Knowledge of the likely levels of virus in potential reservoir plants can be used to inform decisions on insect vector control strategies and may help to prevent virus disease outbreaks in the future.     

Mechanical transmission of maize rayado fino marafivirus (MRFV) to maize and barley by means of the vascular puncture technique

Maize rayado fino marafivirus (MRFV) was mechanically transmitted to kernels of three Costa Rican maize cultivars by the vascular puncture technique. A transmission rate of up to 43.2% was obtained for cultivar HC-57. The rate of MRFV transmission to maize was possibly affected by the morphology of the kernel, which may influence physical access to the vascular tissue after water imbibition. Transmission to maize was confirmed by western blot and immunosorbent electron microscopy. By slight modifications of the procedure, MRFV was also transmitted to barley. This is the first report of MRFV infecting a species outside the supertribe Andropogonodae. Virus infection and replication in barley were confirmed by RT-PCR detection of MRFV RNA and by detection of the virus by ELISA.     

6种病毒抑制剂对西藏青稞上大麦黄矮病的防治效果

通过田间小区试验,开展了6种病毒抑制剂对西藏青稞上大麦黄矮病防治效果的研究.采用带毒蚜虫人工接种法,于青稞起身拔节期每株接种10～15头带毒麦长管蚜,7 d后灭蚜,灭蚜后3d喷施病毒抑制剂,在成株期出现黄矮病症状后调查病株率、病情指数、防治效果,以及长势和产量.结果表明,6种病毒抑制剂对青稞上大麦黄矮病有不同程度的防治...     

Mathematical models of cross protection in the epidemiology of plant-virus diseases

ABSTRACT Mathematical models of plant-virus disease epidemics were developed where cross protection occurs between viruses or virus strains. Such cross protection can occur both naturally and through artificial intervention. Examples of diseases with continuous and discontinuous crop-host availability were considered: citrus tristeza and barley yellow dwarf, respectively. Analyses showed that, in a single host population without artificial intervention, the two categories of host plants, infected with a protecting virus alone and infected with a challenging virus, could not coexist in the long term. For disease systems with continuous host availability, the virus (strain) with the higher basic reproductive number (R(0)) always excluded the other eventually; whereas, for discontinuous systems, R(0) is undefined and the virus (strain) with the larger natural transmission rate was the one that persisted in the model formulation. With a proportion of hosts artificially inoculated with a protecting mild virus, the disease caused by a virulent virus could be depressed or eliminated, depending on the proportion. Artificial inoculation may be constant or adjusted in response to changes in disease incidence. The importance of maintaining a constant level of managed cross protection even when the disease incidence dropped was illustrated. Investigations of both pathosystem types showed the same qualitative result: that managed cross protection need not be 100% to eliminate the virulent virus (strain). In the process of replacement of one virus (strain) by another over time, the strongest competition occurred when the incidence of both viruses or virus strains was similar. Discontinuous crop-host availability provided a greater opportunity for viruses or virus strains to replace each other than did the more stable continuous cropping system. The process by which one Barley yellow dwarf virus replaced another in New York State was illustrated.     

灰飞虱传播的一种小麦病毒病鉴定

 在实验室中利用灰飞虱接种小麦时出现一种新的病毒病症状,鉴定表明其病原为大麦黄条点花叶病毒(Barley yellow striate mosaic virus, BYSMV)。采用生物学测定、电镜观察、RT-PCR检测和序列分析的方法,明确了该病毒的粒体特性、危害症状及田间发生情况。接种试验表明该病毒通过灰飞虱传播,接种7~10 d后小麦新生叶片出现黄色斑点、斑驳,继而发展成黄色条纹,叶片对生且细而窄,重病株新叶扭曲,叶鞘不能伸长,病株矮化。对小麦病叶超薄切片电镜观察,发现细胞质中存在大量弹状病毒粒子,病毒粒体大小为（315~353）nm×（46~57） nm。利用特异性引物从病株总RNA中扩增出 565 bp基因片段,序列同源性分析显示与大麦黄条点花叶病毒(Barley yellow striate mosaic virus, BYSMV) Zanjan-1分离物聚合酶（L）基因对应序列的一致性为97 %,与北方禾谷花叶病毒(Northern cereal mosaic virus, NCMV) L基因对应序列的一致性为78 %~79 %。对采自河北邯郸、石家庄、保定、唐山的31株样品进行RT-PCR检测,25株检测到BYSMV,7株检测到水稻黑条矮缩病毒(Rice black streaked dwarf virus,RBSDV),其中5株为2种病毒复合侵染,结果表明BYSMV的田间分布较广。系统发育分析表明BYSMV-Lab/TS/ZX/QY 4个分离物与本研究的BYSMV亲缘关系密切。BYSMV是我国小麦上新发现的一种弹状病毒,并已形成危害,暂定名为小麦黄条纹矮缩病,应加强流行动态监测。     

Evaluation of various methods for the detection of barley yellow dwarf virus by the tissue-blot immunoassay and its use for virus detection in cereals inoculated at different growth stages

Various modifications of the tissue-blot immunoassay (TBIA) for the detection of barley yellow dwarf virus (BYDV, luteovirus) were compared. Similar results were obtained by using three different labelled molecules; goat anti-rabbit antibodies conjugated to alkaline phosphatase, protein A conjugated with alkaline phosphatase and goat anti-rabbit antibodies conjugated with colloidal gold. Blocking the nitrocellulose membrane with polyvinyl alcohol for 1 min was effective and allowed the procedure to be shortened by one hour. TBIA was sensitive enough to detect BYDV in old dry tissue wich had been soaked in water for 1 h.BYDV was monitored by TBIA in wheat, oat and barley after inoculation at heading, flowering and grain filling growth stages. The later the inoculation date, the greater the chance of detecting the virus in stem bases rather than in the upper part of the stem. The later the inoculation the less virus moved, from the inoculated tiller to other tillers of the same plant.     

吉林、黑龙江毛葱病毒病调查

本研究为明确吉林和黑龙江省毛葱病毒病发生率,从两省5个地区共采集255份毛葱样品。根据毛葱4种主要病毒基因组序列设计特异性引物,对胡葱黄条病毒Shallot yellow stripe virus(SYSV)和青葱X病毒Shallot virus X (SVX)、洋葱黄矮病毒Onion yellow dwarf virus (OYDV)和葱潜隐病毒Shallot latent virus (SLV)进行双重RT-PCR检测。结果表明,229份样品检出病毒,带毒率为89.8%,SLV的检出率最高,达87.06%,OYDV次之,为36.86%,SYSV检出率偏低,为0.78%;同时存在病毒复合侵染,其中双病毒复合侵染为SLV和OYDV,检出率为33.3%;三病毒复合侵染为SYSV、OYDV和SLV,检出率为0.78%,未发现4种病毒复合侵染。本研究为吉林和黑龙江种植区毛葱病毒病防治提供了参考依据。     

我国草莓主栽区病毒种类的鉴定

 病毒种类鉴定结果表明我国草莓主要栽培区存在草莓斑驳病毒、草莓轻型黄边病毒、草莓镶脉病毒和草莓皱缩病毒。四种病毒的总侵染株率达80.2%,其中单种病毒侵染株率为41.6%,两种或两种以上病毒复合侵染株率为38.6%。前三种病毒均为球状病毒,粒体直径分别为25-30nm、23nm和50nm;皱缩病毒为杆状病毒,大小为380×70nm。传染性试验的结果证实,草莓病毒可通过嫁接、菟丝子传染,但不能通过机械传染。桃蚜可传染斑驳病毒和轻型黄边病毒,其传毒关系前者为非持久性后者为持久性。田间桃蚜蚜虫口密度高峰期与草莓病毒侵染盛期相吻合。     

Infection of oats and other cereals by oat chlorotic stunt virus in the field and laboratory

During 1992/1993 and 1994/1995, field experiments were carried out to investigate the infection of several cultivars of oats, other cereals and grasses, with oat chlorotic stunt virus (OCSV), which is provisionally identified as a member of the Tombusviridae . Under field conditions a high percentage of oat plants became infected when sown in infested soil and there was little difference in susceptibility between the oat cultivars compared. Although plants of other Poaceae such as winter wheat, winter barley and annual meadow grass also became infected, the percentage was low and the virus titre reached was much lower than in oats. In most infected plants the virus was localized within the roots, and only in a few plants did it spread systemically. This suggests that the virus was acquired through the roots, indicating further similarities between OCSV and members of the Tombusviridae . Several cereals, including oats, wheat, barley and maize, were infected by mechanical inoculation using an embryo-wounding technique; in the majority of cases virus infection only reached a low titre.     

Leek yellow stripe virus and its relationships to onion yellow dwarf virus; characterization,ecology and possible control

Since 1970 yellow stripe disease of leek (Allium porrum) has developed epidemically in the south-eastern part of the Netherlands coincident with increasing year-around cultivation of the crop. Many autumn and winter crops now become totally infected. Apparently similar attacks, first reported in Germany in 1937, are increasingly attracting attention in various European countries. This paper describes the leek yellow stripe virus (LYSV) as a new potyvirus related to onion yellow dwarf virus (OYDV), which was so far incompletely described. LYSV is hardly infectious to onion (A. cepa) and shallot (A. ascalonicum) and OYDV behaves similarly on leek. The leek virus further differs from OYDV in not being infectious toA. fistulosum and in causing distinct local lesions onChenopodium amaranticolor andC. quinoa. The two viruses closely resemble each other in external symptoms in their respective hosts, in persistence of infectivity in expressed sap, and in particle morphology and length (LYSV 820 nm; OYDV 833 nm). Intracytoplasmic inclusion bodies slightly differ. Further biophysical characters of the two viruses, such as sedimentation coefficient (OYDV 143 S), buoyant density in CsCl (LYSV 1.326; OYDV 1.306, or 1.258 in Cs₂SO₄), and molecular mass of coat protein subunit (LYSV 34000; OYDV 30000 dalton), are characteristic of the potyvirus group, but do not assist in judging their relationships. Serologically they are only distantly related if at all. The leek virus is not seed-borne. It is aphid-transmitted in the non-persistent manner and its main epidemic build-up is during late summer and autumn. The sole sources of infection are nearby leek crops. Awaiting the development of resistant leek cultivars, it is advised to avoid sowing leek seed beds and planting spring crops near overwintering leek, and to remove infected plants showing up during summer.     

Novel cytopathological structures induced by mixed infection of unrelated plant viruses

ABSTRACT When two unrelated plant viruses infect a plant simultaneously, synergistic viral interactions often occur resulting in devastating diseases. This study was initiated to examine ultrastructural virus-virus interactions of mixed viral infections. Mixed infections were induced using potyviruses and viruses from other plant virus families. Novel ultrastructural paracrystalline arrays composed of co-infecting viruses, referred to as mixed virus particle aggregates (MVPAs), were noted in the majority of the mixed infections studied. When the flexuous rod-shaped potyvirus particles involved in MVPAs were sectioned transversely, specific geometrical patterns were noted within some doubly infected cells. Although similar geometrical patterns were associated with MVPAs of various virus combinations, unique characteristics within patterns were consistent in each mixed infection virus pair. Centrally located virus particles within some MVPAs appeared swollen (Southern bean mosaic virus mixed with Blackeye cowpea mosaic virus, Cucumber mosaic virus mixed with Blackeye cowpea mosaic virus, and Sunn hemp mosaic virus mixed with Soybean mosaic virus). This ultrastructural study complements molecular studies of mixed infections of plant viruses by adding the additional dimension of visualizing the interactions between the coinfecting viruses.     

引起辣椒花叶、枯顶的一个病毒分离物的鉴定

 从河北望都辣椒地分离到一株辣椒病毒分离物.测定表明能侵染茄科、苋科、豆科、菊科、藜科的25种植物,不能侵染葫芦科和十字花科等13种植物.桃蚜（Myzus persicae）非持久性传毒;钝化温度65—70℃,稀释限点10^-4—10^-5体外保毒期6天（20—22℃）;病毒颗粒呈球形,直径约25nm;ISEM测定它与蚕豆萎蔫病毒（BBWV）关系密切;电镜下观察到BBWV所特有的长管状内含体和布纹状结晶体,认为该分离物是BBWV.但寄主范围和寄主反应与文献报道的BBWV各分离物有所不同,可能是另一毒株。