改造病毒基因组增强病毒杀虫剂杀虫效率研究进展

由于基因工程技术的发展和安全性研究的深入,以重组杆状病毒为主的重组昆虫病毒杀虫剂的应用正面临着突破。文章综述了通过修饰或删除昆虫病毒某些基因、插入控制宿主发育、代谢激素或酶的基因、删除、修饰昆虫病毒基因组中特定的基因以扩大宿主域、应用RNA干扰技术提高昆虫病毒杀虫效率等构建重组昆虫病毒杀虫剂的技术路线,展望重组病毒杀虫剂的发展趋势。     

Genetically engineered viral insecticides: New insecticides with improved phenotypes

Baculoviruses are natural pathogens of insects which have been used as biopesticides. In contrast to many chemical agents, baculoviruses affect only a limited number of insects and so can be used to target particular insect species. Unfortunately, unless the host receives a very high virus dose, the insect continues to feed and causes damage to crops, because the virus takes several days to kill it. This lag is unacceptable in the protection of many crops, especially where cosmetic damage seriously reduces the value of a crop (e.g. fruit). Strategies have been devised recently to circumvent this problem. The baculovirus genome has been modified, using genetic engineering techniques, to incorporate foreign genes encoding insect-specific toxins, or hormones or enzymes. Expression of some of these genes in the virus-infected host insect has been shown to reduce both the feeding damage to crop plants and the time taken to kill the insect pest. The current status of this developing field is described, together with an assessment of the possible risks involved in using such genetically modified agents in the environment.     

应用昆虫毒素基因构建重组病毒杀虫剂研究进展

由于基因工程技术的发展和安全性研究的深入,以重组杆状病毒为主的重组昆虫病毒杀虫剂的应用正面临着突破。文章综述了通过插入昆虫专一性毒素基因构建重组昆虫病毒杀虫剂的技术路线,展望重组病毒杀虫剂的发展趋势。     

斯氏线虫-致病杆菌共生体侵染昆虫的生物标志物

昆虫病原线虫是一类专性侵染和寄生昆虫的病原线虫,是非常重要的生防资源。斯氏线虫属Steinernema和致病杆菌属Xenorhabdus通过形成共生体在侵染昆虫过程中共同完成生活史,其中致病杆菌释放效应物质引发昆虫败血症是其重要机制。该文对斯氏线虫-致病杆菌共生体的侵染策略和在侵染过程中产生的免疫调节因子、释放的毒素蛋白和活性代谢物进行概述,其中,苯乙酰胺作为免疫抑制因子促进自身定殖,脂多糖作为内毒素引起寄主血细胞裂解,Tc毒素蛋白作为外毒素导致寄主中肠上皮细胞溶解,活性代谢产物如xenematides、fabclavine和PAX肽等具有抑菌、诱导细胞凋亡等活性。而斯氏线虫本身也能够产生表皮/分泌蛋白来抑制寄主免疫,与共生菌协同致死寄主。因此,通过对斯氏线虫-致病杆菌共生体产生的致病物质进行汇总分析,为研究昆虫病原线虫致病机制提供理论参考,同时也为新型绿色杀虫剂的开发和应用提供证据支持。     

棉铃虫核型多角体病毒分子生物学和基因工程研究进展

棉铃虫核型多角体病毒(HaSNPV)是棉铃虫专一性病原物,隶属于杆状病毒科核型多角体病毒属.对其分子生物学和基因工程的研究主要包括以下几个方面:测定了HaSNPV G4株和C1株基因组核苷酸全序列,并与其它病毒进行了同源性比较;研究了HaSNPV部分基因的结构、转录、表达及其功能.构建了HaSNPV Bac to Bac杆状病毒表达系统;重组病毒杀虫剂的研究为HaSNPV大面积防治棉铃虫展示了广阔的前景.随着棉铃虫核型多角体病毒分子生物学和基因工程研究的不断深入,重组病毒杀虫剂将在棉铃虫综合防治中发挥更为重要的作用.     

Potential consequences of field releasing virus infected endoparasitoids

The principal intent of rearing and field releasing of endoparasitoids is to control targeted insect pests. The key objectives of this paper are to demonstrate a need for producing disease free endoparasitoids for field releases, and to show that field releases of a virus infected endoparasitoid such as Microplitis croceipes, may actually harm its field population by infecting it with a virulent virus. The nonoccluded baculovirus of M. croceipes shortens the life span of its hosts, reduces their reproductive capacity, reduces parasitization potential, and thus reduces the value of the endoparasitoid as a biological control agent     

北京地区花生病毒病及流行规律研究

1985—1987年研究表明北京地区花生上流行的病害主要有黄瓜花叶病毒CA株系(CMV-CA)引起的黄花叶病害和花生轻斑驳病毒(PMMV)引起的轻斑驳病害。血清鉴定451份花生病害样品,黄花叶病害样品受CMV-CA侵染占95.7％,轻斑驳病害样品受PMMV侵染占91.3％,中后期病害样品受CMV-CA和PMMV复合感染较普遍。CMV种传率2％左右,种传病苗在花生出苗后开始出现,6月病害进入高峰。三年CMV-CA流行程度明显不同,主要取决于苗期蚜虫发生早晚、发生量及苗期降雨量。PMMV种传率低于1％,病苗出现稍晚,但病害扩散快,6月上旬进入高峰,7月上、中旬发病率达100％。三年流行程度差异不明显。     

杆状病毒新的分类地位和书写方式

2020年10月ICTV更新了主要病毒名录，该文件新增了纳尔达病毒纲Naldaviricetes和勒乏病毒目Lefavirales。勒乏病毒目含中有包括杆状病毒科Baculoviridae在内的3个科，而杆状病毒科分为4个属：甲型杆状病毒属Alphabaculovirus、乙型杆状病毒属Betabaculovirus、丙型杆状病毒属Deltabaculovirus和丁型杆状病毒属Gammabaculovirus，该名录中杆状病毒科有85个主要种。根据ICTV网站病毒名称和种名的书写规范，杆状病毒的种名由其宿主昆虫的种名和病毒特性词（如nucleopolyhedrovirus和granulovirus）组成，其中宿主昆虫的属名首字母大写，其余字母均小写。病毒的种名（在用于系统分类时）书写全部用斜体，但其他情形时病毒名称（包括其宿主的属和种名）均采用正体书写。杆状病毒名称的缩写一般采用宿主属名和种名的前两位双字母＋病毒特性词缩写的方式，但16种传统杆状病毒的缩写仍沿用宿主的属名和种名首位单字母＋病毒特性词的缩写的方式。     

Advances and prospects in potato virology with special reference to virus resistance

Knowledge of the nucleotide sequences in the genomic nucleic acid of several potato viruses has enabled the open reading frames to be identified. These open reading frames are expressed by a variety of strategies, to produce proteins with functions in virus nucleic acid replication, virus particle production, cell-to-cell transport of virus and virus transmission by vectors. The activity of such proteins depends on their interactions with other viral or non-viral materials.Several other biological properties of plant viruses can also be related to individual viral gene products. For example, in plants co-infected with a specific pair of unrelated viruses, one virus can benefit from an ability to use the gene product of the second virus in replication, cell-to-cell transport or transmission by vectors. Similarly, different host resistance genes are targeted against viral replicase, movement protein or coat protein. Thus it is becoming possible to relate gene-for-gene (or more accurately, viral gene domain-host gene) interactions to events at the molecular level. Genetically engineered resistance to plant viruses likewise can be targeted against individual viral genes, and probably also against viral regulatory sequences. Such transgenic resistance seems likely to be as durable as conventional host resistance but durability should be improved by producing plants with combinations of resistances of different kinds, either conventional or genetically engineered, or both.     

Prevention of virus epidemics by a crop-free period in the arava region of Israel

In the isolated Arava region of Israel, virus epidemics in vegetables were avoided by enforcing a crop-free period of one month during June-July. It was found that the cultivated crops are the major reservoir of viruses, and that during these months the insect vector population and the natural virus sources are low. Therefore, a one-month crop-free period was declared during June-July, and since its enforcement in 1986, no economic damage caused by insect-borne viruses has been recorded. Contribution from the Agricultural Research Organization. No. 2323-E, 1997 series     

Prospects for the development of a genetically engineered baculovirus insecticide

Baculoviruses are insect-specific pathogens which have been employed for the natural control of insect pests for many years. They present an alternative to the use of chemical agents for crop protection. Their restricted host range enables particular pest species to be targeted, and this prevents any loss of beneficial insects from a treated area. However, their large-scale development as insect control agents has been limited because they take longer to kill the host following infection than rapidly-acting chemical insecticides. The aim of genetic modification of baculoviruses is to increase their speed of action, while preserving their beneficial characteristics, so creating a fast-acting, environmentally friendly insecticide. The prospects for achieving this are discussed in this paper, with consideration of scientific progress and the influence of economic and legislative factors.     

Development of the Multi-nucleocapsid Nucleopolyhedroviruses (MNPVs) Infectious to Loopers (Lepidoptera: Noctuidae: Plusiinae) as Microbial Control Agents

A number of the members of the Noctuidae (subfamily Plusiinae) are polyphagous insects that infest a variety of economically important crops world-wide. These hosts include but are not limited to cotton, vegetable and field crops and also such specialty crops as mint. Many of these crops require multiple applications of chemical pesticides to protect them from various loopers and other economic pests. One proposed alternative to the use of chemical pesticides to protect these crops is the development of insect-specific viruses of the family Baculoviridae. Hundreds of these viruses of the genus Nucleopolyhedrovirus have been isolated, many from economically important Lepidoptera. The advent of the discovery that some of these viruses may have a broad host range increased the interest in the development of them as microbial agents throughout the world. The broad host range (over 30 species in some cases) provided the possibility to control not only one species, but a complex of lepidopterous pests infesting specific or multiple crops. From the 1960s to the present, extensive basic and applied research has been conducted on the multi-nucleocapsid (MNPV) forms within which a broad host range appears to be characteristic. Of these, the virus isolated from the alfalfa looper, Autographa californica (Speyer) (AcMNPV) has been the most studied, particularly as related to microbial control. Two of the viruses isolated from loopers have been registered in the USA. Although efficacy has been demonstrated for loopers, there is a paucity of data on the other important species that may simultaneously infest looper hosts. Because of their relatively slow action, the viruses will probably be used in integrated programs with chemical pesticides applied during critical periods of high population pressure. Further research needs to be conducted to establish efficacy for other hosts, improved production methods either in vivo or in vitro, increased field persistence as related to timing and frequency of applications, and finally the utility of genetically engineered MNPVs as microbial pesticides. The potential of these organisms has been demonstrated and new developments are being made to increase the overall efficiency and economics of their use. These improvements can only increase interest in use of the baculoviruses in pest management systems for loopers and other pests.     

豌豆病毒病病原研究

 1986年至1990年,从豌豆田中采集了150余份病毒病样本,鉴定出蚕豆萎蔫病毒(BB-WV)、芜菁花叶病毒(TuMV)、马铃薯Y病毒组分离物、黄瓜花叶病毒(CMV)、莴苣花叶病毒(LMV)、大豆花叶病毒(SMV)、豌豆花叶病毒(PMV)、菜豆黄花叶病毒(BYMV)和苜蓿花叶病毒(AMV)等9种病毒。样本中,BBWV所占的比例最高,达59.2%,其次为CMV,占15.5%。BBWV常与CMV复合侵染豌豆,LMV发生也较普遍。田间调查表明,豌豆病毒病发病率因种植地区及品种不同而有差异,平均发病率为12.4%。     

应用伪钝绥螨防治苹果全爪螨初报

伪钝绥螨是叶螨的有效天敌,1986年引入天水,1987、1988年在苹果园进行了释放试验,6月中、下旬按1:50的益害比释放于苹果树上,结果表明经过35～40天,苹果全爪螨从峰期(1987、7、31)7.79头/叶和(19888、2)21.84头/叶开始减退,至50～60天,分别减退为1.76头/叶和1.90头/叶,而对照树分别为19.43头/叶(8、20)和44.15头/叶(8、2)。该螨对苹果全爪螨越冬卵的控制效果明显,释放树平均一年生枝条单枝含卵量为15.95粒,化防树为93.64粒。     

Factors in the Success and Failure of Microbial Insecticides in Forestry

The minor position of microbial insecticides within the global pesticide market can be attributed to a number of causes, including high cost of production, high specificity, poor application technology, poor persistence and slow speed of kill. These aspects are discussed in relation to the potential for use of microbial insecticides against forest pests. Many of the constraints are not limiting in forestry and some of the ways in which they can be overcome are discussed, including the concept of a better appreciation of the ecological context. This approach encompasses knowledge of the behaviour of the target host species, both for improved targeting and for maximum exploitation of secondary inoculum. These, and other aspects are brought together in discussing the future for microbial insecticides in forest pest management.     

Breeding for viral resistance: conventional methods

Conventional breeding methods based primarily on the principles of Mendelian genetics have provided the basis for the majority of resistance to viruses in potato cultivars. This development of resistant cultivars has resulted from sexual hybridisation followed by selection of the best genetic recombinant. Selection is one of the most powerful tools available for crop improvement. Successful selection depends on reproducible genetic variability, ability to identify genetically superior individual plants or families, populations large enough to ensure the likely occurrence of rare genetic combinations, and the combination of resistance expression with commercial utility. Resistance to the major potato viruses namely potato virus A, potato virus M, potato virus S, potato virus X, potato virus Y and potato leafroll virus has been studied and selected for. A number of different types of resistance have been identified including (a) major gene resistance; (b) minor gene resistance; and (c) immunity. With the exception of potato leafroll virus, stable resistance to the other viruses has been achieved either singly or in combination in a range of potato cultivars. In addition for both potato leafroll virus and potato virus Y, the focus has been on the development of resistance to aphid transmission of the viruses.     

甜菜花叶病毒病的研究Ⅰ.病毒的分离鉴定

 1986-1987年对黑龙江、内蒙古部分甜菜原料产区与采种区进行了初步调查,采种区甜菜花叶病毒病发病率达100%,与其邻近的原料产区有零星发病,远离采种区则没有发病的迹象。田间采集的病叶,用磨擦、蚜传接种方法均能在甜菜上再现症状。经昆诺藜(Chenopodium quinoa)分离,普通电镜及乳胶电镜负染均能看到典型的马铃薯Y组病毒的粒体。通过鉴别寄主、甜菜上的症状表现,分离物的物理特性及血清学试验,证明此分离物为甜菜花叶病毒。在提纯方面,摸索了不同方法,认为匀浆前液氮或冷冻处理,二次PEG沉淀后过Sepharose4B柱,分离病毒效果较好,还可省去超速离心步骤。以内蒙五号甜菜品种作为毒源的繁殖寄主,能使提纯病毒产量达0.6mg/100g叶片,耳静脉与多点皮下注射相结合免疫兔子,微量沉淀测定效价为1:1024。     

Detection and typing of tomato yellow leaf curl viruses

The denomination Tomato yellow leaf curl virus (TYLCV) comprises several viruses that cause severe damage to tomato crops in warm and temperate regions worldwide. TYLCV viruses are widespread in the Mediterranean Basin, in which two species have been reported: Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV, previously TYLCV-Is). The availability of methods convenient for the diagnosis of these viruses is essential. We have investigated several alternatives for reliable detection and differentiation of TYLCSV and TYLCV. Triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) proved to be very useful for large-scale diagnosis in field situations, but lacked discriminating capacity and sensitivity in the stages of infection in which low virus titre is present. The DNA-based methods are suited to laboratory operations and plant disease clinics, where accuracy of detection and discrimination of viruses is required. Polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) was the most reliable method to discriminate between TYLCSV and TYLCV, but is not suited to high sample turnover. For large-scale testing, tissue print hybridization assay provides a reliable and sensitive alternative to PCR.     

虫酰肼对苜蓿银纹夜蛾核型多角体病毒的增效作用

研究了以甜菜夜蛾为靶标害虫时,昆虫生长调节剂虫酰肼对苜蓿银纹夜蛾核型多角体病毒(AcNPV)的增效作用.结果表明:虫酰肼在作用于甜菜夜蛾时对AcNPV有显著增效作用,不仅可提高杀虫毒力,而且也能提高杀虫速度.作用于3龄和4龄幼虫时,6.67 mg/L虫酰肼对AcNPV的增效比分别是1.31和3.62,使害虫因表现感染病毒症状而死亡的LT50(致死中时)分别缩短10.8%和6.5%,使害虫因病毒和虫酰肼作用而死亡的LT50分别缩短25%和20.4%.虫酰肼和病毒协同作用还显著抑制了幼虫的生长发育,在协同作用1天后,幼虫体重即显著低于单用病毒或对照,并且随着作用时间的延长,协同作用组幼虫体重与病毒单剂组及对照组的差异越来越大.但6.67mg/L虫酰肼和2.7×105PIB/mL AcNPV协同作用于幼虫期时,其对存活幼虫发育为成虫后的繁殖力无影响,成虫产卵量、交配率、卵孵化率以及卵孵化幼虫数等均与病毒单剂及虫酰肼单剂无显著差异,也与对照无显著差异.     

The transmission of geminiviruses by Bemisia tabaci

The cosmopolitan whitefly species, Bemisia tabaci (Gennadius) and Trialeurodes taporariorum (Westwood) have always been regarded as pests to a large range of worldwide crops. Both species are capable of transmitting plant viruses, with T. vaporariorum being the vector of only a few ‘clostero’-like viruses and B. tabaci the vector of viruses in several groups. The largest group of viruses transmitted by B. tabaci are the geminiviruses and B. tabaci is known to transmit around 60 members. Until recently, B. tabaci had been associated with only a limited range of host plants within any one region, although its total potential host range was large. Virus transmission was confined within the plant host range of each regional population of B. tabaci. The emergence of the polyphagous ‘B’ biotype of B. tabaci with its increased host range of more than 600 plant species, has resulted in geminiviruses infecting previously unaffected crops. As the ‘B’ biotype spreads further into Europe, European field and glasshouse crops have been shown to be susceptible to whitefly-transmitted viruses already endemic to other parts of the world. More than 20 colonies of B. tabaci, including both ‘B’ and non-‘B’ biotypes from disparate global locations have been compared for their ability to transmit more than 20 geminiviruses. All but two highly host-specific colonies were capable of transmitting most geminiviruses tested. However, some viruses were transmitted more efficiently than others. The virus coat protein or capsid is essential for vector recognition and transmission. By comparing transmissible viruses at the molecular level to viruses that are no longer whitefly-transmissible, the active epitope on the virus coat protein could be identified for designing future virus control strategies.