禾谷多粘菌传麦类病毒研究进展

综述了近10年来浙江省农业科学院在禾谷多粘菌生态学、传播病毒特性、超微结构特征、体内病毒粒子观察、所传播的麦类病毒种类、基因组序列测定、血清学关系、病毒自发缺失突变及其机理、病害发生规律以及抗源筛选等方面的研究进展。     

Serological relationships between the cylindrical inclusion proteins of potyviruses

ABSTRACT Antisera to the cytoplasmic inclusion proteins (CIPs) of bean yellow mosaic (BYMV), clover yellow vein (ClYVV), turnip mosaic (TuMV), sweet potato feathery mottle (SPFMV), and maize dwarf mosaic (MDMV) potyviruses were used to examine the relationships between the CIPs of 18 potyviruses. The antisera to CIPs of BYMV, ClYVV, TuMV, and SPFMV cross-reacted to most or all of the purified CIPs tested in western blot assays. The MDMV CIP antiserum reacted significantly only to the MDMV and sorghum mosaic virus CIPs. Reactivity of antisera to CIPs of dicot-infecting viruses was generally higher with CIPs of other dicot-infecting than with monocot-infecting potyvirus CIPs. Analysis of amino acid sequences of the CI genes of 11 well-characterized potyviruses suggested that epitopes specific for individual potyviruses are primarily in the C-terminal domains of the CIP, whereas epitopes shared among different viruses are clustered in the N-terminal domains. The most highly conserved predicted epitope overlaps the nucleotide binding motif of the N-terminal helicase domain of the CIP. Antibodies to this domain will probably be present in antisera to any potyvirus CIP and contribute to the cross-reactivity observed. Differences in the C-terminal domains may correlate with interactions between the CIP and coat protein necessary for replication and movement.     

Phylogenetic relationships between rice dwarf phytoreovirus isolates from five countries

Rice dwarf virus isolates were collected from several locations in Japan, the Philippines, China, Nepal and Korea. Genomic dsRNA segment profiles in polyacrylamide gel electrophoresis differed among the isolates. There were less differences in the profiles between isolates from Japan and Korea than in those between these two Countries and others. Nucleic acid hybridization was used to examine the extent of genomic variation. Full-length cDNAs to all genomic segments encoding non-structural proteins (S4, S6, S9, S10, S11 and S12) were synthesized from two Japanese isolates, and were used for dot-blot hybridization. Hybridizations using probes generated from the full-length cDNA clones failed to differentiate isolates from different geographical areas. However, cDNA probes covering a variable region of S12 were able to distinguish Japanese and Korean isolates from those of other countries. Phylogenetic tree analysis based on the amino acid sequence of P12 encoded by S12 grouped Japanese and Korean isolates together. The Chinese isolates from two different locations (Yunnan and Fujian) were closely related to each other, and were the most distantly related to Japanese and Korean isolates.     

中国甘薯病毒种类的血清学和分子检测

 2009～2010年,从我国18个省（市）采集了176份表现病毒病症状的甘薯样品。利用血清学、PCR和核苷酸序列测定的方法,对上述样品中的病毒种类进行了鉴定。血清学检测结果表明,供试样品中甘薯羽状斑驳病毒（SPFMV）的阳性率最高,达56.3%,其次为甘薯G病毒（SPVG）和甘薯类花椰菜花叶病毒(SPCaLV),阳性率分别为34.1%和33.5%。PCR和核苷酸序列测定结果表明,我国甘薯上至少存在SPFMV、SPVG、甘薯潜隐病毒（SPLV）、甘薯褪绿斑病毒（SPCFV）、甘薯褪绿矮化病毒（SPCSV）、黄瓜花叶病毒（CMV）、甘薯脉花叶病毒（SPVMV）和甘薯卷叶病毒（SPLCV）8种病毒。此外,供试样品中没有检测出甘薯轻斑驳病毒（SPMMV）,是否存在甘薯轻斑点病毒(SPMSV)、SPCaLV和C 6病毒尚不能确定。     

Morphological and molecular identification of potato and cereal cyst nematode isolates from Algeria and their phylogenetic relationships with other populations from distant theirgeographical areas

A nematode survey conducted in 2013 in Algeria, revealed that potato cyst nematodes (PCN) and cereal cyst nematodes (CCN) are widely distributed in several potato and cereal growing regions of the country. Sixteen PCN populations from five localities and five CCN populations from four of these localities were collected and characterized at the morphological and molecular levels. The PCN populations were identified as Globodera rostochiensis and G. pallida occurring separately or in mixed populations. Two species of CCN were detected. Heterodera avenae was found in four localities, whereas H. hordecalis only in one locality in association with H. avenae. The morphological and morphometric identification of PCN and CCN was confirmed by diagnostic ITS-RFLP profiles and sequencing. Phylogenetic analysis of the ITS, D2-D3 expansion domains of the 28S rRNA gene and 18S rRNA gene was made for PCN and CCN populations. Globodera pallida and G. rostochiensis from Algeria show great similarity with European and South American populations. Because of the high divergence among Algerian populations of G. pallida and G. rostochiensis it can be assumed that they were multi-introduced in Algeria. The most divergent population of G. pallida, that formed a well-separated group with some populations from Chile and Peru, suggests a later or independent introduction of this population into Algeria. Heterodera avenae and H. hordecalis formed a well-supported cluster with the corresponding populations.     

Serological reaction of beet western yellows and potato leafroll viruses in ELISA

The detection of potato leafroll virus (PLRV) and beet western yellows virus (BWYV) and their serological relatedness were investigated by the double sandwich ELISA (DS). In both pure preparations and crude plant extracts, an unequivocal detection of each of these viruses was obtained by DS, provided the homologous antisera were used. No detection was achieved when the heterologous antisera were used, although purified virus could be detected when using the heterologous antisera for coating, providing the homologous antisera were used as conjugates. Therefore, for routine screening of BWYV or PLRV infection in plants, the DS method with homologous antisera can be used. However, it does not seem that BWYV infection in potato could be detected by the routine DS aimed for PLRV screening. In immunosorbent electron microscopy, PLRV and BWYV could be easily detected by coating grids with either homologous or heterologous antiserum. This and the possibility of trapping each virus in ELISA plates with the heterologous antiserum indicate serological cross-reactivity between PLRV and BWYV.     

Serological detection of plant viruses in their aphid vectors and host plants in Tunisia

DAS-ELISA was used to study the presence of viruses in four aphid species ( Aphis gossypii , Aphis craccivora , Myzus persicae and Macrosiphum euphorbiae ) and in their host plants potato, capsicum and tomato. Samples were collected in different regions in Tunisia: north, Cap Bon, Sahel, centre and south. A. gossypii and M. persicae carried all the viruses detected: Cucumber mosaic cucumovirus , Tomato aspermy cucumovirus , Tobacco etch potyvirus , Potato Y potyvirus , Alfalfa mosaic alfamovirus and Potato leafroll polerovirus . These two aphids were also those that occurred most frequently on the crops concerned.     

丛枝菌根真菌与小麦孢囊线虫的相互作用

 近年来, 小麦孢囊线虫(cereal cyst nematodes, CCN:主要病原为燕麦孢囊线虫Heterodera avenae)对小麦(Triticum aestivum)的危害日益严重, 亟待探索新的生防途径。丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)作为环境功能生物, 对寄主植物具有生物药肥双重作用, 不仅能促进植物吸收利用养分, 而且能拮抗土传病原物、提高植物抗病性。本研究以AMF与CCN相互作用为切入点, 试图明确AMF与CCN相互作用关系, 并科学评价不同AMF抑制CCN、降低病害的效应。试验于温室盆栽条件下进行, 设接种AMF Gigaspora margarita(Gi.m)、Glomus mosseae(G.m)、Glomus intraradices(G.i)、Glomus versiforme(G.v)、Gi.m +G.m+G.i+G.v、CCN、CCN+Gi.m、CCN+G.m、CCN+G.i、CCN+G.v、CCN+Gi.m+G.m+ G.i+G.v和不接种对照(CK)共12个处理。结果表明, 接种AMF各处理均能降低小麦孢囊线虫侵染率、土壤中孢囊数和根内J2数量, 其中Gi.m处理抑制效果最大;CCN不同程度减少AMF侵入点数和产孢数量。Gi.m 和CCN+Gi.m处理的根内丛枝着生数量最多, 而后者根内的超氧化物歧化酶、苯丙氨酸解氨酶和过氧化氢酶活性显著高于其他处理、丙二醛含量则显著低于其他CCN+AM真菌处理。Gi.m和G.i处理的小麦株高、地上部干重高于其他处理;Gi.m 和CCN+Gi.m的处理的单穗重和单株产量均高于其他处理。表明AMF能不同程度拮抗CCN、促进小麦生长和提高产量, 其中, Gi.m是高效菌种。结论认为, AMF与CCN之间存在一定相互抑制作用, AMF能通过诱导植株防御反应拮抗CCN。     

Variation for isozymes and double-stranded RNA among isolates of Puccinia striiformis and two other cereal rusts

Gel electrophoresis was used to examine the variation in isozymes and dsRNA within and between the rust species Puccinia striiformis, P. recondita and P. hordei. No differences in isozyme phenotype were found among 29 diverse isolates of the wheat-attacking form of P. striiformis (WYR). Smaller numbers of isolates of the barley-attacking form (BYR) of P. recondita and of P. hordei showed similar intra-group uniformity. There were major differences in isozyme phenotypes between the three species, while WYR and BYR differed for two of 12 enzymes. Double-stranded RNA was detected in each species and in all 26 isolates examined. For WYR and BYR, all isolates within each group had the same or a similar phenotype. In contrast, each isolate of P. recondita and P. hordei had a unique phenotype. There were differences in dsRNA phenotypes both between the three species and between WYR and BYR.
The uniformity of these rust populations and species for isozyme phenotype is contrasted with their variability in pathogenicity and with the variability in isozymes encountered in higher organisms. Uniformity may result from a feature of the biology of the rust species and populations examined, or from the relative homogeneity of the environment of biotrophic pathogens. Consistent differences in isozyme and dsRNA phenotype between the WYR and BYR isolates of P. striiformis indicate that these are two discrete populations, supporting the view that they should be recognized as f.sp. tritici and f.sp. hordei , respectively.     

Synergy between grapevine vitiviruses and grapevine leafroll viruses

An interactive relationship between vitiviruses and grapevine leafroll viruses was characterized in grapevine. Grapevine viruses A and B (GVA and GVB) were found more frequently in the presence of co-infecting Grapevine leafroll associated viruses (GLRaV-1, ?2 or ?3) than in their absence. The titers of the vitiviruses in co-infection with leafroll viruses were found to be higher than were their titers in the absence of leafroll virus infection. The occurrence of vitivirus-associated stem-pitting symptoms was correlated with leafroll virus co-infection. Specific pairing associations on the species level were found between different viti- and leafroll virus species: GVB was associated preferentially with GLRaV-2; GVA was associated preferentially with GLRaV-1 and GLRaV-3. In contrast to the increase in vitivirus titer seen with leafroll virus co-infection, the incidence and titer of grapevine leafroll virus appeared to be unaltered by vitivirus co-infection. The potential for a synergistic enhancement of grapevine disease in co-infected vines is discussed.     

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.     

Dose-response relationships between phytopathogenic bacteria and their hosts

Theories on the relationships between the challenge dose of phytopathogenic bacteria and the quantal response of the host plant are discussed and applied to experimental results. In a number of cases the extent of disease was directly proportional to the dose, which is an indication of independent action. Departures from linearity in the relationships were ascribed tointer alia a shortage of multiplication sites, antagonism amongst the cells of the pathogen and heterogeneity of the tested host plants with respect to susceptibility. In a few host-pathogen combinations, dose-response relationships showing an upward curve were found; this is probably an indication of facultative synergism. The relationships found in homologous and heterologous host-pathogen combinations were similar. The implications of the above findings for the quantitative study of factors affecting the susceptibility of plants to bacterial infection are discussed.Samenvatting Na een bespreking van de theorieën over de relatie tussen het aantal fytopathogene bacteriën per inoculatie en de al-of-niet respons — waarbij dus de grootte van de individuele respons niet in acht genomen wordt — worden deze theorieën getoetst aan de resultaten van proeven die in de literatuur beschreven zijn. Onderschied wordt gemaakt tussen proeven waarin de proporties en die waarin de aantallen geslaagde inoculaties bepaald zijn. Verder is een vergelijking gemaakt tussen homologe en heterologe combinaties van waardplant en pathogeen.Waar de proporties geslaagde inoculaties werden gemeten, vond ik in een aantal gevallen evenredigheid tussen dosis en respons, mits een transformatie werd toegepast voor veelvoudige infectie. Dit is een aanduiding dat de cellen van het pathogeen elkaar niet beïnvloeden. Afwijkingen van dit rechtlijnig verband kunnen o.a. worden toegeschreven aan antagonisme tussen de cellen van het pathogeen, aan heterogeniteit in vatbaarheid van de waardplanten of aan een beperkt aantal vermeerderingsloci.In drie gevallen werd een naar boven gekromde lijn gevonden, hetgeen waarschijnlijk wijst op facultatief synergisme.In proeven waarin de aantallen geslaagde inoculaties gemeten werden, vond ik in de literatuur evenredige en dus rechtlijnige verbanden met afbuigingen naar rechts voor responses tot te hogere doses. De afwijkingen van rechtlijnigheid kunnen hier worden toegeschreven aan een beperkt aantal vermeerderingsloci of aan antagonisme tussen de cellen van het pathogeen.Geen essentieel verschil in dosis-respons verhoudingen werd gevonden tussen homologen en heterologe waardplant-pathogeen combinaties.De implicaties van bovengenoemde resultaten voor de kwantitatieve studie van factoren die de vatbaarheid van planten voor infectie door bacteriën bepalen, worden besproken.     

5种化学除草剂对薇甘菊防治效果及对其他植物的影响

为了筛选高效防除薇甘菊的除草剂,本文利用4种含灭草松或吡啶类的新型除草剂25％苄嘧磺隆·灭草松AS、25％滴酸·灭草松AS、25％滴酸·氨氯吡AS、25％氟胺·灭草松AS,以常用除草剂24％滴酸·二氯吡AS作对照,在深圳进行防除薇甘菊的试验研究.除草剂对薇甘菊防效结果表明:400 mL/hm2 25％滴酸·氨氯吡AS和...     

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。     

昆虫拒食剂与其它药剂的区别

本文论述了植物性昆虫拒食剂抑制昆虫取食的特点和使昆虫致死的作用机理 ,并比较了昆虫拒食剂与其它药剂的区别。