Threats to Japanese agriculture from newly emerged plant viruses and viroids

International trade is one of the main ways by which a species can expand its geographical range. Since the beginning of the twenty-first century, the worldwide distribution of many pests has increased through the international circulation of crop seeds and seedlings. In this review, viruses and viroids that have invaded Japan since 2000 are described in order of their prevalence. Measures to prevent invasion by such viruses and viroids and protect agricultural production in Japan from alien pests are discussed.     

Extraction and electrophoretic analysis of large dsRNAs from desiccated plant tissues infected with plant viruses and biotrophic fungi

Extraction and electrophoretic analysis of large dsRNAs from plant and fungal tissues has been used successfully to detect RNA viruses infecting plants, fungi, and oomycetes. We modified a previously reported dsRNA extraction protocol and used it to detect a wide variety of plant and putative fungal viruses from infected plant tissues. The modified protocol was used successfully to extract large dsRNAs from 50 to 70 mg of desiccated plant tissues infected with acute and persistent RNA viruses and from plant tissues infected with biotrophic fungi causing rusts and powdery mildew diseases. The protocol proved to be efficient, fast, economic and versatile and requires relatively small amounts of desiccated tissue.     

Sensitive detection of two plant viruses by enzyme-amplified elisa

Enzyme-amplified ELISA (enzyme-linked immunosorbent assay) increased the sensitivity of detection of citrus tristeza virus and papaya ringspot virus in plant sap by 25- and 125-fold, respectively, compared with direct double antibody sandwich ELISA. The advantages of the new substrate system for the detection of low concentrations of viruses in plants are discussed.     

Plant-derived ribosome-inactivating proteins involved in defense against plant viruses

European Journal of Plant Pathology - Plant viruses are the most serious pathogens causing severe damage to crops worldwide. A variety of conventional strategies are currently being employed to...     

三种外检植物病毒的灭活处理

番茄环斑病毒（ＴｍＲＳＶ），烟草环斑病毒（ＴＲＳＶ），南芥菜花叶病毒（ＡｒＭＶ）的病汁液和ＰＥＧ粗提纯液，经适宜温度或甲醛处理，均丧失侵染性而有抗原性。ＴｍＲＳＶＰＥＧ粗提纯液经６０℃（水浴）处理１０分钟或２８℃７天，ＴＲＳＶ粗提纯液置２５℃一个月，Ａｒ－ＭＶ在４０℃７天条件下均可做为阳性对照的灭活处理的最佳方案。可保存抗原性在７～１２月以上。为了防止危险性检疫病毒的侵入，对入境种苗进行检疫，需建立快速、准确、标准化检疫程序，而在血清学快速诊断试验中，提供阳性对照，对提高判断准确率是必要的。因此，为了解决在诊断试剂中提供阳性对照但又不能使其检疫性病毒人为扩散这一重要问题，我们在研究三种外检病毒（ＴｍＲＳＶ，ＴＲＳＶ，ＡｒＭＶ）的检验技术的同时，又进行了一些灭活试验，用化学和物理方法钝化病毒，使其失去侵染性而保持抗原性，并应用于酶联诊断试剂盒中，本文报道了初步试验结果     

An analysis of the durability of resistance to plant viruses

ABSTRACT Genetic resistance often fails because a resistance-breaking (RB) pathogen genotype increases in frequency. On the basis of an analysis of cellular plant pathogens, it was recently proposed that the evolutionary potential of a pathogen is a major determinant of the durability of resistance. We test this hypothesis for plant viruses, which differ substantially from cellular pathogens in the nature, size, and expression of their genomes. Our analysis was based on 29 plant virus species that provide a good representation of the genetic and biological diversity of plant viruses. These 29 viruses were involved in 35 pathosystems, and 50 resistance factors deployed against them were analyzed. Resistance was found to be durable more often than not, in contrast with resistance to cellular plant pathogens. In a third of the analyzed pathosystems RB strains have not been reported, and in another third RB strains have been reported but have not become prevalent in the virus population. The evolutionary potential of the viruses in the 35 pathosystems was evaluated with a compound risk index based on three evolutionary factors: the population of the pathogen, the degree of recombination, and the amount of gene and genotype flow. Our analysis indicates that evolutionary potential may be an important determinant of the durability of resistance against plant viruses.     

植物病毒的分类与命名现状

 年以前,植物病毒与动物病毒的分类系统不同,前者分为组(group)、亚组(subgroup)、成员(member),而后者分为科(family)、属(genus)、种(species)^[1,2]。     

10种植物病毒的基因芯片检测技术研究

 本研究设计了10种植物病毒和各种对照的探针, 将探针固定在醛基化玻璃片基上制备基因芯片。用常规的Trizol法提取植物总RNA, 根据病毒的外壳蛋白基因或复制酶基因设计特异性引物, 经RT-PCR扩增相应区段并用Cy3-dCTP进行标记。将标记的PCR产物与芯片杂交, 扫描仪对杂交结果扫描, GenePix Pro 4.0软件对杂交图像进行分析。结果表明, 该芯片可以从病毒感染样本中检测到特异性识别信号, 检测灵敏度比RT-PCR高10~100倍, 所以, 基因芯片能对植物病毒作出快速、准确的检测。     

Quality control in bioassays used in screening for plant viruses

Test plants are often used for broad screening for plant viruses. Mechanical inoculation of a series of test plants enables generic detection of mechanically transmitted viruses in only 1 assay. Moreover, such an assay is suitable for known as well as unknown viruses and their variants. However, in comparison to serological and molecular methods, quality control in bioassays is almost never addressed. The system of positive and negative controls, blind samples and proficiency tests is applicable, provided that a broader interpretation of positive and negative controls is used. For validation, performance criteria can only be determined for individual viruses. However, results can often be extrapolated. Sensitivity is addressed by dilution and expressed as a relative value. Specificity has to consider the virus species and the plant species to be tested. Selectivity mostly depends on the plant species tested, because some hosts contain components that inhibit transmission. Repeatability and reproducibility, determined for a limited number of samples, appears high, as also substantiated by the authors' experience. This paper details how EPPO Standards on quality control were implemented by the National Plant Protection Organization of the Netherlands (NPPO‐NL). This information will be of use for other laboratories that wish to introduce quality control in bioassays for virus testing.     

植物病毒与媒介昆虫互作促进其传播的研究进展

近年来植物病毒病频发,严重制约着农作物的产量与品质。绝大多数植物病毒依赖媒介昆虫进行传播,而传播的关键是病毒如何突破昆虫的肠屏障、唾液腺屏障和卵屏障等多个生物屏障。植物病毒一方面利用其外壳蛋白或非结构蛋白突破媒介昆虫的中肠屏障和唾液腺屏障;另一方面则与昆虫体内卵黄原蛋白、共生菌以及精子表面蛋白发生特异性互作,促进病毒跨越卵障碍,最终实现病毒在昆虫体内复制。此外,植物病毒还能通过侵染寄主植物影响其防御性状,间接改变媒介昆虫生理及其行为反应,促进病毒在植物间的传播。该研究对植物病毒突破昆虫生物屏障的分子机制,以及植物病毒-植物-媒介昆虫互作对于病毒传播的影响进行了综述,并对阻断病毒传播的方法进行展望。     

单管多重RT-PCR同时检测大豆种子中三种检疫性植物病毒

我国大豆年进口量持续增长,快速、准确地检测进境大豆种子中可能携带的病原物是防止检疫性有害生物入境传播和扩散的有效手段。菜豆荚斑驳病毒(BPMV)、烟草环斑病毒(TRSV)和番茄环斑病毒(ToRSV)均是被大豆种子携带的检疫性有害生物。本研究建立了在单一PCR管中同时检测这3种检疫性植物病毒及大豆内源基因Bd-30K的多重RT-PCR方法。研究结果表明,所建立的多重RT-PCR方法具有较好的特异性和灵敏度,检测含BPMV、TRSV和ToRSV RNA的最低浓度分别为0.45、0.0093和0.004ng/μL,从大豆种子中同时检测3种病毒的最低RNA浓度为0.58ng/μL。     

外来入侵植物病毒在我国的发生、危害与管理

外来入侵植物病毒已经严重威胁全球多个国家和地区的农业生产。预防和控制入侵植物病毒能够确保农业安全生产和可持续发展。本文详细地总结与综述了我国重要外来入侵植物病毒发生与危害情况。结合国内外生物入侵防治经验与我国入侵植物病毒的实际情况,分析了我国植物病毒入侵防控面临的挑战,提出了我国入侵植物病毒防控的几种通用措施。     

Host factors used by positive-strand RNA plant viruses for genome replication

Replication of positive-strand RNA [(+)RNA] viruses proceeds through well-orchestrated actions of both viral and host factors. Remarkable features of eukaryotic (+)RNA virus replication include hijacking of host factors by viral components and remodeling of intracellular membranes to establish the viral replication factory, where viral RNA is synthesized. Here we review recent progress in our understanding of how (+)RNA plant viruses use host factors to create favorable environments for viral RNA replication.     

植物病毒在媒介昆虫体内的垂直传播研究进展

对于多数植物病毒而言,其在田间的自然扩散主要依赖昆虫等介体生物,而媒介昆虫的垂直传播是植物病毒长期存在并发生的重要原因。对媒介昆虫垂直传播病毒机制的研究不仅可以为未来开发高效低毒农药奠定基础,更可为植物病毒与昆虫的互作和病毒病的预测预报提供新的视野及角度。媒介昆虫在植物病毒传播过程中的具体作用在近几年被广泛研究。该文综述了近年来植物病毒在昆虫体内垂直传播的研究进展,包括昆虫传播植物病毒的方式、植物病毒在昆虫体内的垂直传播方式以及虫媒病毒垂直传播的可能机制等。在整个垂直传播的过程中,植物病毒的衣壳蛋白、磷蛋白和媒介昆虫唐氏综合症细胞黏附分子、硫酸乙酰肝素糖蛋白、热激蛋白以及卵黄原蛋白,甚至共生菌都有参与。最后,基于媒介昆虫和植物病毒的关系对未来植物病毒病的绿色防控和生物防控进行了展望。     

高通量测序技术在植物及昆虫病毒检测中的应用

在过去的十几年中,测序技术的发展为分子生物学领域带来了革命性的变化。第二代测序(next-generation sequencing,NGS)技术以快速、高灵敏性、高通量、非序列依赖性等特点极大地促进了病毒诊断学研究领域的发展。NGS技术可以在不了解病毒的生物学特性、血清学特点及基因组信息情况下快速检测未知病毒。通过对总核酸样本进行NGS可以获得某个特定生态环境或种植系统中的所有病毒序列,即病毒组。通过大量的NGS数据可以分析寄主中某一病毒的基因组变化、构建病毒的准种以及研究病毒的进化和起源。本文介绍了高通量测序的方法在植物和昆虫病毒检测中的应用。