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。     

植物病毒经介体昆虫唾液腺水平传播至寄主韧皮部机制的研究进展及展望

很多植物病毒经介体昆虫以持久循回型的方式水平传播至寄主韧皮部致病，而唾液腺是介体昆虫持久传毒的重要器官，也是植物病毒在介体昆虫内循回需要克服的最后一道防线。持久性植物病毒要完成水平传播，必须突破昆虫唾液腺屏障的阻碍，因此病毒和介体昆虫间形成了“攻”与“守”的较量与对决。揭示持久性植物病毒克服昆虫唾液腺屏障，实现水平传播的机制，对病害控制具有重要意义。该文着眼于介体昆虫唾液腺在持久传毒过程中的重要功能，回顾了虫传植物病毒突破介体昆虫唾液腺侵入屏障和释放屏障的分子机制，探讨了昆虫唾液蛋白通过调节植物或昆虫的适应性和行为促进或抑制病毒水平传播的功能，为制定阻断介体昆虫传播植物病毒途径的防控策略提供理论依据。     

水稻矮缩病毒对黑尾叶蝉卵巢发育与产卵量的影响

虫传植物病毒须依靠媒介昆虫进行传播和扩散,而植物病毒在媒介昆虫体内的复制和转运会对昆虫产生直接或间接影响.Sinisterra等[1]报道称媒介昆虫携带病毒后寿命缩短、产卵量下降.     

昆虫与弹状病毒互作的研究进展

近年来宏基因组学研究的普及大大丰富了人们对RNA病毒多样性的认识,但对这些新发现病毒的生物学特性却所知甚少。本文围绕RNA病毒中一类重要的负单链RNA病毒--弹状病毒与其昆虫寄主互作的研究进行综述,总结已发现的弹状病毒及其昆虫寄主类型,共有20个属144种弹状病毒可以感染14个属的昆虫;根据已有的系统进化研究对弹状病毒的寄主起源进行推测;并以感染黑腹果蝇Drosophila melanogaster的sigma病毒(Drosophila melanogaster sigma virus,DMelSV)为主要对象,就弹状病毒引起的CO2麻痹致死症状以及昆虫寄主对其的免疫反应研究进行总结,而在对黑腹果蝇的研究中发现很多非经典免疫通路中的新抗病毒基因,暗示存在新的抗病毒免疫通路;通过飞虱、叶蝉与其传播的植物弹状病毒以及长须罗蛉Lutzomyia longipalpis与其传播的脊椎动物病毒的互作研究,发现Toll、IMD信号通路、细胞自噬及小RNA干扰(small interfering RNA,siRNA)通路等可能与昆虫对弹状病毒的免疫反应相关。昆虫是弹状病毒主要的寄主和媒介,也是病毒遗传多样性的储主,因此更好地研究和了解昆虫寄主与弹状病毒的相互关系,有助于病毒致病和传播机制以及昆虫抗病毒免疫机理的深入研究。     

昆虫内共生菌-昆虫-植物互作关系研究进展

在长期的协同进化过程中,昆虫与其体内的共生菌建立了密切的互利共生关系。昆虫内共生菌不仅能调控宿主昆虫的营养代谢和生殖代谢,还能协助昆虫抵御生物、非生物胁迫,提高昆虫对化学农药的抗性及对寄主植物的适应性等。因此,内共生菌是宿主昆虫生长发育及适应性的重要调控因子。目前,随着组学技术的不断发展,内共生菌在宿主昆虫和寄主植物中的原位功能不断被挖掘,通过对内共生菌-昆虫-植物互作模型的研究,将进一步揭示昆虫内共生菌与昆虫、植物的互作机理,加深对昆虫适应性机制的理解并推进新型害虫防控和靶标技术的研发。本文就昆虫内共生菌的起源、特点、分布和传递,昆虫内共生菌在昆虫-植物-环境互作中的作用,以及昆虫内共生菌研究的方法和新技术等方面进行了综述,并对未来昆虫内共生菌介导的防御效应及昆虫适应性机理等热点问题进行了展望。     

水稻黑条矮缩病毒在灰飞虱消化系统的侵染和扩散过程

 水稻黑条矮缩病毒 (Rice black streaked dwarf virus, RBSDV) 由介体灰飞虱(Laodelphax striatellus Fallén)以持久增殖型方式传播, 其编码的P9 1蛋白是形成病毒复制和子代病毒粒体装配的场所—病毒原质(viroplasm)的组分之一。为了明确RBSDV在介体昆虫体内的侵染循回过程, 本研究通过原核表达的P9 1蛋白免疫注射兔子制备P9 1抗体, 应用免疫荧光标记技术研究P9 1在饲毒后不同时期的介体灰飞虱体内的定位。共聚焦显微镜观察到饲毒后3 d, P9 1出现在介体中肠的少数上皮细胞内;饲毒后6 d, 在中肠外表的肌肉细胞分布有P9 1;饲毒后10 d, P9 1分布于中肠和后肠表面的肌肉, 同时在唾液腺也能观察到P9 1的存在。结果表明RBSDV在介体灰飞虱体内首先侵染中肠上皮细胞并复制, 随后扩散到中肠表面的肌肉细胞, 并通过环肌和纵肌扩散到中肠和后肠, 最后扩散到唾液腺。本研究首次直观地阐述了RBSDV在灰飞虱消化系统的侵染和扩散过程, 为有效阻断灰飞虱携带并传播病毒奠定基础。     

昆虫共生微生物在病虫害防治的研究进展

昆虫体内的共生微生物是一大类生物群体，包括细菌、真菌、病毒及一些小型原生生物，它们广泛分布于昆虫体内，具有参与昆虫体内合成氨基酸、维生素等小分子营养物质，分解纤维素等大分子化合物，以及降解杀虫剂和植物次生代谢物等作用。此外，也能间接调控宿主生物的免疫系统，从而阻断病原体的复制和传播。因此，在害虫防治和控制虫媒病毒传播等方面具有应用潜力。该文综述昆虫共生微生物在病虫害防治方面的最新研究进展，探讨其生物学功能、与宿主的作用机制、宿主对病原微生物的适应机制以及在病虫害防治中应用等方面的研究进展，并对未来发展趋势及在害虫防治方面的应用前景进行展望。     

取食感染大麦黄矮病毒小麦后麦二叉蚜体内保护酶和解毒酶活性变化

<正>植物病毒与介体昆虫之间存在互作关系,病毒会通过感染寄主植物或介体昆虫而间接或直接影响介体昆虫的适合度(Hu et al.,2013)。昆虫取食携带病毒植物后可能会引起自身的防御反应或调节反应。解毒酶和保护酶是昆虫体内的重要酶系,在对抗逆境及维持昆虫正常生理生化代谢方面具有重要作用(刘建业等,2017)。麦二叉蚜Schizaphis graminum是全球性农业害虫,除刺吸植物汁液、分泌蜜露     

Q型烟粉虱对番茄斑萎病毒的获取、保持及在非传毒寄主棉花上的适合度

正番茄斑萎病毒(tomato spotted wilt virus,TSWV)可使花生、番茄、辣椒和曼陀罗等多种植物致病,西花蓟马Frankliniella occidentalis是其媒介昆虫,而烟粉虱Bemisia tabaci并不能高效传播TSWV,为非媒介昆虫(Pan et al.,2013)。植物病毒不仅可以与媒介昆虫发生相互作用,还可以直接或间接修饰非媒介昆虫的行为,导致非媒介昆虫适合度的改变(Chen et al.,2017)。田间自然条件下,Q型烟粉虱在感染TSWV的寄主上取食,TSWV可能对携毒Q型烟粉虱的寄     

西花蓟马传播番茄斑萎病毒研究进展

西花蓟马Frankliniella occidentalis是世界性重要检疫性害虫之一,不仅直接取食危害作物而且传播病毒,从而造成极为严重的经济损失。由于西花蓟马在我国具有广泛的适生范围,随其入侵我国并随之传播的番茄斑萎病毒(Tomato spotted wilt virus)已在我国不同地域发现,对经济作物已形成严重威胁。本文综述了西花蓟马对番茄斑萎病毒的获取、携带和传播扩散过程及其病毒在蓟马体内的循环过程和机理,总结了影响西花蓟马传播番茄斑萎病毒效率的因素,并评述了西花蓟马-病毒-植物这一互作系统及其对西花蓟马生长发育适合度的影响,以期为我国西花蓟马传播番茄斑萎病毒的基础研究和防控提供理论依据与指导。     

蚜虫传播非持久性病毒的取食行为调控机制

蚜虫能够传播上百种植物病毒，是最重要的农业介体昆虫之一。蚜虫在刺探和取食植物过程中，唾液组分会连同附着在口针中的病毒粒子一同被分泌进入植物内，在调节植物诱导抗性、病毒侵染扩散、介体昆虫行为等过程中均有重要作用。本文围绕蚜虫传播病毒和获取病毒2个关键过程，总结分析了蚜虫独特的刺吸取食行为与传毒效率和获毒效率之间的联系；针对取食活动中关键的唾液蛋白在调控植物免疫抗性、帮助病毒侵染过程中的功能，阐述了蚜虫高效传播非持久病毒的分子基础；针对蚜虫的获毒过程，综述了病毒侵染植物间接调控蚜虫趋向和行为的作用方式。这些研究的开展将为解释蚜虫和病毒协同侵染的分子机制以及有效开展基于蚜虫取食行为调控的病虫害防控新技术提供思路。     

Genetic Regulation of Polerovirus and Luteovirus Transmission in the Aphid Schizaphis graminum

ABSTRACT Sexual forms of two genotypes of the aphid Schizaphis graminum, one a vector, the other a nonvector of two viruses that cause barley yellow dwarf disease (Barley yellow dwarf virus [BYDV]-SGV, luteovirus and Cereal yellow dwarf virus-RPV, polerovirus), were mated to generate F1 and F2 populations. Segregation of the transmission phenotype for both viruses in the F1 and F2 populations indicated that the transmission phenotype is under genetic control and that the parents are heterozygous for genes involved in transmission. The ability to transmit both viruses was correlated within the F1 and F2 populations, suggesting that a major gene or linked genes regulate the transmission. However, individual hybrid genotypes differed significantly in their ability to transmit each virus, indicating that in addition to a major gene, minor genes can affect the transmission of each virus independently. Gut and salivary gland associated transmission barriers were identified in the nonvector parent and some progeny, while other progeny possessed only a gut barrier or a salivary gland barrier. Hemolymph factors do not appear to be involved in determining the transmission phenotype. These results provide direct evidence that aphid transmission of luteoviruses is genetically regulated in the insect and that the tissue-specific barriers to virus transmission are not genetically linked.     

A theoretical assessment of the effects of vector-virus transmission mechanism on plant virus disease epidemics

ABSTRACT A continuous-time and deterministic model was used to characterize plant virus disease epidemics in relation to virus transmission mechanism and population dynamics of the insect vectors. The model can be written as a set of linked differential equations for healthy (virus-free), latently infected, infectious, and removed (postinfectious) plant categories, and virus-free, latent, and infective insects, with parameters based on the transmission classes, vector population dynamics, immigration/emigration rates, and virus-plant interactions. The rate of change in diseased plants is a function of the density of infective insects, the number of plants visited per time, and the probability of transmitting the virus per plant visit. The rate of change in infective insects is a function of the density of infectious plants, the number of plants visited per time by an insect, and the probability of acquiring the virus per plant visit. Numerical solutions of the differential equations were used to determine transitional and steady-state levels of disease incidence (d*); d* was also determined directly from the model parameters. Clear differences were found in disease development among the four transmission classes: nonpersistently transmitted (stylet-borne [NP]); semipersistently transmitted (foregut-borne [SP]); circulative, persistently transmitted (CP); and propagative, persistently transmitted (PP), with the highest disease incidence (d) for the SP and CP classes relative to the others, especially at low insect density when there was no insect migration or when the vector status of emigrating insects was the same as that of immigrating ones. The PP and CP viruses were most affected by changes in vector longevity, rates of acquisition, and inoculation of the virus by vectors, whereas the PP viruses were least affected by changes in insect mobility. When vector migration was explicitly considered, results depended on the fraction of infective insects in the immigration pool and the fraction of dying and emigrating vectors replaced by immigrants. The PP and CP viruses were most sensitive to changes in these factors. Based on model parameters, the basic reproductive number (R(0))-number of new infected plants resulting, from an infected plant introduced into a susceptible plant population-was derived for some circumstances and used to determine the steady-state level of disease incidence and an approximate exponential rate of disease increase early in the epidemic. Results can be used to evaluate disease management strategies.     

Evidence of no horizontal or vertical transmission of tomato severe rugose virus by Bemisia tabaci MEAM1

Bemisia tabaci is important in agriculture worldwide, mainly because it is a vector of numerous plant viruses, probably the most important of which are members of the genus Begomovirus. Dozens of begomoviruses have been reported to infect tomato plants in Brazil, although tomato severe rugose virus (ToSRV) predominates in tomato crops. ToSRV, found so far only in Brazil, is efficiently transmitted by B. tabaci MEAM1. However, no studies have assessed the occurrence of vertical and horizontal transmission of the virus in the insect, which may have epidemiological consequences affecting disease management. This study evaluated the possibility of transmission of ToSRV between whiteflies during copulation and transovarial transmission from viruliferous females of B. tabaci MEAM1 to their progeny. Transmission of ToSRV did not occur during mating between males and females of B. tabaci MEAM1. Aviruliferous males and females confined with viruliferous insects of the opposite sex were also unable to transmit the virus to tomato plants. ToSRV was detected, by PCR, in the ovaries of viruliferous females of B. tabaci MEAM1 but not in eggs, nymphs, or adults of the progeny of viruliferous females. Adult progeny of viruliferous females also did not transmit ToSRV to tomato plants. Together, the results indicate that vertical and horizontal transmission of ToSRV by B. tabaci MEAM1 is unlikely. Sustainable management of the tomato golden mosaic disease caused by ToSRV should continue to focus on using resistant varieties, managing sources of inoculum around tomato fields, and rational chemical control of the vector.     

Genetic engineering of insect viruses for insect biological control

Insect viruses can be exploited for the biological control of insect pests and serve as well as vehicles for the introduction of ‘foreign genes’ into insect cells and insects. The present work describes some of the molecular events that take place during the replication of theGalleria mellonella densonucleosis virus in the insect host. Viral RNA and protein synthesis were monitored. An understanding of the virus biology is essential for further implementation of these viruses for biological control purposes.     

Genetic engineering of insect viruses for insect biological control

Insect viruses can be exploited for the biological control of insect pests and serve as well as vehicles for the introduction of ‘foreign genes’ into insect cells and insects. The present work describes some of the molecular events that take place during the replication of theGalleria mellonella densonucleosis virus in the insect host. Viral RNA and protein synthesis were monitored. An understanding of the virus biology is essential for further implementation of these viruses for biological control purposes.     

Population biology and epidemiology of plant virus epidemics: from tripartite to tritrophic interactions

Natural enemies have long been used in biological control programs to mitigate the damage caused by herbivory. Many herbivorous insect species also act as plant virus vectors, enabling virus transmission from plant to plant and hence disease development in a plant population. Whilst an intuitive assumption would be to expect a decrease in vector numbers to lead to subsequent reductions in virus transmission, recent evidence suggests that introduction of natural enemies (parasitoids and predators) may in some cases increase plant virus transmission while at the same time reducing vector numbers. In this paper we review the evidence for plant-virus-vector-natural enemy interactions, the signalling mechanisms involved and their implications for virus transmission, and show how a modelling approach can assist in identifying the key parameters and relationships involved in determining the disease outcome. A mathematical model linking the population dynamics of a vector-parasitoid system with virus transmission was used to investigate the effects of virus inoculation and acquisition rates, parasitoid attack rate and vector aggregation on disease dynamics across a wide range of parameter value combinations. Virus spread was found to increase with enhanced inoculation, acquisition and parasitoid attack rate but decrease with high levels of vector aggregation.     

Some characteristics of the transmission of grapevine leafroll associated virus 3 by Planococcus citri Risso

Some characteristics of the acquisition and transmission of GLRaV-3 by Planococcus citri were determined by ELISA testing and transmission experiments. Groups of five insects were used, i.e. the advisable minimum group size suggested by the results of ELISA of insect groups of various sizes. The virus was transmitted to only 1/10 test plants each of which had been exposed to a group of insects fed on GLRaV-3 infected plants for at least three days, eventhough more than 80% of the insect groups were expected to contain viruliferous individuals under these conditions. Viruliferous mealybugs transferred to potato plants could retain the virus for up to 24 h, but lost the capacity for effective transmission to vines within 1 h after transfer. In newly infected vines, the virus remained latent or undetectable by ELISA for at least 13 months.