十字花科蔬菜CMV类群与株系划分初步研究

陕西主要菜区十字花科蔬菜上的ＣＭＶ分为５个类群。其中的Ａ类群侵染十字花科植物为主，可区分为轻花叶、中度花叶和重花叶３个株系。当前田间发生以轻花叶株系为主，占６９．９％。     

Comparison and differentiation of Wheat Yellow Mosaic Virus(WYMV), Wheat Spindle Streak Mosaic Virus (WSSMV) and Barley Yellow Mosaic Virus (BaYMV) isolates using WYMV monoclonal antibodies

Twelve monoclonal antibodies (MAbs) were obtained by immunizing mice with a French isolate (F1) of wheat yellow mosaic virus (WYMV). Three of these (3D12, 2C1, 6C3) belong to the IgM class and the nine others to the IgG class (3D8, 3H1, 2B8, 1F2, 3C10, 4F12, 3H9, 1G5, 54). In antigen-coated plate (ACP) ELISA and indirect double antibody sandwich (IDAS) ELISA, all MAbs recognize the WYMV (F1) both in the form of purified particles and in wheat leaf extract. The analysis of numerous French isolates of WYMV shows a variable reactivity with MAbs 3D8, 3H1, 2B8, 3C10, 3H9 and 1G5 in IDAS — and ACP-ELISA. The Japanese isolate of WYMV and United States isolates of wheat spindle streak mosaic virus (WSSMV) were detected in IDAS- and ACP-ELISA by ten of the MAbs tested showing that the wheat bymoviruses originating from the three locations share a high epitopic homology. French isolates of barley yellow mosaic virus (BaYMV; pathotypes 1 and 2) were only detected in ACP-ELISA with MAbs 6C3, 3D8, 3H1 and 2B8 whereas the two Japanese strains (I-1, II-1) of MaYMV were recognized with these and also with that of 3C10. In IDAS-ELISA, the two Japanese strains were clearly detected by MAbs, 6C3, 3D8, 3H1, 1F2, 3C10 and 1G5 and the British and Belgian (pathotype 2) isolates only by that of 6C3. Only the Japanese strain of BaYMV, 1-1 could be detected with MAb 3H9 in this ELISA system.     

Spread and control of Cucumber Mosaic Virus in gladiolus

Cucumber mosaic virus (CMV) and bean yellow mosaic virus are the most prevalent viruses in gladiolus fields in Israel. Factors affecting infection were studied, as a basis for the buildup of virus-tested propagation material. Marked differences in the susceptibility of gladiolus cultivars to aphid-borne infection were observed, both in field experiments and in test aphid inoculations. Cultivars ‘Euro-vision’ and ‘Trader Horn’ were resistant, while ‘Peter Pears’ and ‘Commando’ were highly susceptible. The aphid that landed most frequently on gladiolus wasMacrosiphum euphorbiae. In test inoculationsM. euphorbiae andAphis gossypii efficiently transmitted CMV from gladiolus to gladiolus, but did not transmit CMV from four other source plants. In field experiments, only those gladioli planted close to infected gladiolus sources became infected. Oil sprays in combination with coarse nets controlled CMV infection in the field efficiently.     

Natural Infection of Wheat by the Type Strain of Soil-borne Wheat Mosaic Virus in a Field in Southern Germany

Molecular analyses revealed that a virus causing a severe disease of wheat in one field in Southern Germany is closely related to the Nebraska type strain of Soil-borne wheat mosaic virus (SBWMV) and only distantly related to Soil-borne cereal mosaic virus that is widely distributed in Europe. The latter virus was not found in the SBWMV-containing leaf samples. This is the first report of the occurrence of SBWMV in Germany, and perhaps in all of Europe, which has been confirmed on the molecular level.     

Characterization and occurrence of Zucchini Yellow Mosaic Virus in Sudan

Zucchini yellow mosaic potyvirus (ZYMV) was isolated in 1993 from a squash plant ( Cucurbita pepo cv. Eskandrani) showing severe leaf and fruit distortions, collected in the Gezira region (Sudan). This isolate (ZYMV-Su) was found to be very closely serologically related if not identical to the type strain from Italy. The host range was mostly limited to Cucurbitaceae but systemic infection was found to occur on sesame ( Sesamum indicum ), an important cultivated crop in Sudan. ZYMV-Su induced mosaic symptoms on the resistant melon accession PI 414723, indicating that it belongs to pathotype 2, but did not cause wilting of melon cv. Doublon. ZYMV-Su was efficiently transmitted by Myzus persicae and Aphis gossypii in a non-persistent manner. Surveys conducted from 1993 to 1995 revealed that ZYMV occurred in the major cucurbit growing areas in Sudan, in a diversity of crops and agroecosystems.     

RNA 2 of Cucumber Mosaic Virus Subgroup I Strain NT-CMV is Involved in the Induction of Severe Symptoms in Tomato

A selection of cucumber mosaic virus (CMV) subgroup I strains originating from Asia and Fny-CMV isolated in USA were studied for their interaction with tomato plants. All strains caused mosaic, fernleaf expression and stunting of tomato plants. Symptom expression was relatively mild after infection with Fny-CMV, T-CMV, Le-CMV and MB-CMV, whereas strains PRC-CMV, NT-CMV and K-CMV caused more severe symptoms. Biologically active clones of NT-CMV RNAs 2 and 3 were generated to construct pseudorecombinant viruses with Fny-CMV to map the symptom determining RNA. The pseudorecombinant FNF-CMV (RNAs 1 and 3 from Fny-CMV, RNA 2 from NT-CMV) showed a similar phenotype on tomatoes to those caused by NT-CMV, whereas FFN-CMV (RNAs 1 and 2 from Fny-CMV, RNA 3 from NT-CMV) induced symptoms comparable to Fny-CMV. The data indicate that CMV RNA 2 of NT-CMV is involved in the induction of severe symptoms in tomato plants.     

Mosaic Virus and Leaf Curl Diseases of Okra in Nigeria

Abstract

The etiology and incidence of okra leaf curl and okra mosaic virus diseases observed in Nigeria are reviewed and the difficulty in evolving a control measure for these two diseases is discussed.     

高粱病毒病的病原及防治对策

高粱病毒病此前未见报道，症状易与高粱炭疽病、大斑病混淆。电子显微镜检测，高粱病毒病由 多种植物病毒复合侵染所致。影响此病的因素有栽培条件、生育期和传毒介体昆虫。提出"以栽培管理为 基础，消灭传毒媒介为重点.辅以药剂防治"的综合防治对策。     

The Components and Deployment of Resistance to Cassava Mosaic Virus Disease

Cassava mosaic virus disease (CMD) is prevalent and causes serious losses in cassava (Manihot esculenta) in southern India and in many parts of sub-Saharan Africa. The disease is caused by viruses of the Geminiviridae that are transmitted by the whitefly Bemisia tabaci and disseminated in the stem cuttings used routinely for propagation. The main approach to control is through the use of virus-resistant varieties, but suitable ones are not always available and susceptible varieties are still widely grown. This explains why CMD continues to be a problem in many areas.CMD-resistant varieties have several features which are considered in this review:- They are not readily infected, even when exposed to large amounts of vector-borne inoculum. When infected they develop symptoms that tend to be inconspicuous and not associated with obvious deleterious effects on growth or yield. Moreover, the symptoms become even less conspicuous as growth proceeds and plants may eventually recover and become symptomless. Infected plants support a low virus content and they are likely to be a poor source of inoculum from which further spread can occur. Virus is not fully systemic within infected plants which can be a source of uninfected planting material when stem cuttings are collected for further propagation. This phenomenon is referred to as reversion and it has an important cleansing effect in restricting or preventing the progressive deterioration in health status that would otherwise occur during successive cycles of vegetative propagation.The available information on the different components of resistance is discussed and it is concluded that they are inter-related features of the same basic mechanism that restricts virus entry, replication and movement within the host. It is argued that the effectiveness and durability of virus-resistant varieties are likely to be influenced by the way in which they are deployed. However, this topic has received little attention from researchers and there is continuing uncertainty on the effects of CMD on the yield of resistant varieties and on the role of phytosanitation. This involves the use of virus-free planting material and the removal (roguing) of any additional diseased plants that occur. Some consider that these procedures complement the use of virus-resistant varieties and should be adopted, whereas others argue that they are unnecessary and inappropriate. It is concluded that there is considerable scope for utilizing resistant varieties more widely and more effectively than at present, but in doing so it is important to avoid eroding the genetic diversity that is currently such a marked feature of cassava cultivation in Africa.     

Serological Analysis and Coat Protein Sequence Determination of Potato Virus Y (PVY) Pepper Pathotypes and Differentiation from Other PVY Strains

The serological relationships of Potato Virus Y (PVY) isolates belonging to the pepper pathotypes 0, 1 and 1-2 were established by enzyme-linked immunosorbent assay (ELISA). PVY pepper pathotypes did not react with monoclonal antibodies which typically recognize non-pepper strains within the PVY group, leading to discrimination between these two groups of strains. No serological differences were found between the three PVY pepper pathotypes. The coat protein (CP) nucleotide and predicted amino acid sequences of the three different PVY pepper pathotypes were determined. The highest sequence similarity was found between pathotypes 0 and 1 (99.2%), while the lowest occurred between these two and pathotype 1–2 (98.1%). PVY strains from potato and tobacco appeared more distantly related. Phenetic analysis of the CP amino acid sequences showed that the PVY pepper pathotypes formed a tightly clustered group separate from other PVY strains.     

葡聚烯糖和Harpin蛋白对两种番茄病害的防治效果

葡聚烯糖是一种在寄主 病原互作过程中来自病原菌的可诱导植物抗病性的激发子[1],具有调控植物的生长、发育和增强抗病性等功能。迄今已知寡糖类制剂可提高芹菜对萎蔫病、黄瓜对猝倒病、大豆对根腐病等的抗性,对采后病害如辣椒和草莓烂果也有显著的防病效果。Ｈａｒｐｉｎ蛋白是植物病原菌ｈｒｐ基因编码的非特异性激发子,已证明多数病原Ｈａｒｐｉｎ蛋白能诱导烟草、马铃薯、番茄、大豆、黄瓜及拟南芥产生过敏反应[2]。该蛋白已于2000年在美国注册并商品化生产,主要用于防治烟草黑胫病、葡萄灰霉病、马铃薯叶斑病等多种病害。番茄是重要的…     

安康市玉米矮花叶病的发生原因及防治对策

玉米矮花叶病(MDMV)是一种病毒病,1963年在美国大发生,损失惨重,1968年在我国河南新乡、辉县等地发现之后,迅速蔓延到华北、西北、西南及华东地区.我市从2001年发现此病后,该病发生逐年加重,以宁陕、岚皋、平利、旬阳、汉滨、汉阴较重,全市每年发病面积3.33～5.33万hm2,平均病田率32.9%,病株率17.72%,严重度为15.04%.     

Potential of Rhizobacteria for Promoting Sorghum Growth and Suppressing Striga hermonthica Development

Journal of Plant Diseases and Protection - The objective of this study was to screen the potential of four plant growth promoting rhizobacteria (PGPR) for growth promotion in sorghum (Sorghum...     

Incidence of Soil-borne Wheat Mosaic Virus in Mixtures of Susceptible and Resistant Wheat Cultivars

The multiplication of Soil-borne wheat mosaic virus (SBWMV) was studied in mixtures of two winter wheat (Triticum aestivum) cultivars, one susceptible (Soissons) and the other resistant (Trémie). Two seed mixtures of susceptible and resistant varieties in ratios of 1 : 1 and 1 : 3 and their component pure stands, i.e. each variety grown separately, were grown in a field infected with SBWMV. The presence of the virus was detected using DAS-ELISA from January to May. The resistant cultivar Trémie showed no foliar symptoms nor could the virus be detected in the leaves or roots. In May, about 88% of plants of susceptible cultivar Soissons grown in pure stands were infected. At this time, the disease reduction relative to pure stands was 32.2% in the 1 : 1 mixture and 39.8% in the 1 : 3 mixture. Optical density (OD) values from ELISA of the infected plants in the two mixtures were consistently lower than that of the infected plants in cultivar Soissons in pure stands. The ELISA index (EI) calculated using three scales of OD values was 65.5% in the susceptible cultivar in pure stands. The value for this index was 19.1% in the 1 : 1 mixture and 7.9% in the 1 : 3 mixture. The plants of the resistant cultivar Trémie infected in the same field and transferred in January to a growth cabinet at 15 °C multiplied the virus and produced viruliferous zoospores. These results show that the resistant cultivar Trémie plays a role in disease reduction in the cultivar mixtures in field conditions. Possible reasons for this are discussed.     

烟嘧磺隆降解菌株DT-4的降解特性及对高粱药害的缓解作用

土壤中烟嘧磺隆残留可对后茬作物产生不同程度药害。为解决玉米地烟嘧磺隆残留对后茬作物高粱药害问题,使用前期筛选出的烟嘧磺隆高效降解菌株绿木霉Trichoderma virens DT-4,通过高效液相色谱-质谱法检测其降解率,利用室内盆栽生测结合田间小区试验方法,确定降解菌株对土壤中烟嘧磺隆降解效果,降低烟嘧磺隆残留对高粱的药害。结果显示,烟嘧磺隆残留浓度在0.0025～0.1 ug/mL范围内,标准曲线线性良好,符合农残分析要求;PDB液体培养基中烟嘧磺隆在DT-4降解菌处理100 h的降解率高达93.00%;菌株最佳降解条件为培养温度35 ℃、pH 5、最适接种量5%、烟嘧磺隆初始质量浓度200 mg/L。盆栽试验土壤中烟嘧磺隆残留浓度为0.075 mg/kg时,加入降解菌DT-4后能够明显缓解高粱的株高、根长、鲜重、叶绿素含量、根系活力和净光合速率等生长发育指标,对高粱生长有明显的促进作用。田间小区试验中,不同剂型降解菌剂处理,高粱抽穗期效果最为显著,降解菌能够将低于60 g a.i./hm²烟嘧磺隆污染土壤的高粱修复至无明显药害水平,且降解菌剂应用效果为粉剂＞菌液。本研究表明高效降解菌株绿木霉DT-4可有效缓解烟嘧磺隆残留对后茬作物高粱的毒害作用,为玉米高粱轮作体系下烟嘧磺隆残留污染土壤的微生物修复提供科学参考。     

小麦梭条花叶病的发生情况调查及流行因素分析

小麦梭条花叶病１９９１年在天长市零星发生，以后为害逐年加重，目前已成为本市春季小麦的主要病害之一。发病田块一般减产１０％～２０％，严重的高达６０％，少数达毁耕程度。为探明该病害在本市的发生为害情况，我们对该病的症状、发生规律及流行因素作了进一步探讨。１症状观察外部症状：感病小麦在三至五叶期后，从新生心叶上出现褪绿条纹，继而发展成为与叶脉平行的条斑，或呈梭条状，梭条斑中心可引起坏死，叶片逐步黄化以至枯死。少数品种心叶严重褪绿时细弱扭曲，有时亦出现葱管状症状。病株根系发育差，新根少，褐色根多。拔节后…     

Comparison of Colletotrichum orbiculare and Several Allied Colletotrichum spp. for mtDNA RFLPs, Intron RFLP and Sequence Variation, Vegetative Compatibility, and Host Specificity

ABSTRACT Based on spore morphology, appressorium development, sequence similarities of the rDNA, and similarities in amplified restriction fragment length polymorphism (AFLP), it has been proposed that Colletotrichum orbiculare, C. trifolii, C. lindemuthianum, and C. malvarum represent a single phylogenetic species, C. orbiculare. In the current study, the phylogenetic relationship among isolates in the C. orbiculare species complex was reassessed. In all, 72 isolates of C. orbiculare from cultivated cucurbit or weed hosts, C. trifolii from alfalfa, C. lindemuthianum from green bean, and C. malvarum from prickly sida (Sida spinosa) were examined for mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs), RFLPs and sequence variation of a 900-bp intron of the glutamine synthetase gene and a 200-bp intron of the glyceraldehyde-3-phosphate dehydrogenase gene, and vegetative compatibility. In addition, host specificity was examined in foliar inoculations on cucurbit, bean, and alfalfa hosts. Inoculations also were conducted on cucumber fruit. Genetically distinct isolates, based on vegetative compatibility, within the species complex (C. orbiculare, C. trifolii, and C. malvarum) had an identical mtDNA haplotype (haplotype A) when examined with each of three different restriction enzymes. Isolates of C. lindemuthianum had a very similar mtDNA haplotype to haplotype A, with a single polymorphism detected with the enzyme HaeIII. The four species represent a phylogenetically closely related group based on a statistical analysis of the 900- and 200-bp intron sequences. However, distinct RFLPs in the 900-bp intron were consistently associated with each species and could be used to qualitatively and quantitatively distinguish each species. Furthermore, each of the species showed distinct host specificity, with isolates of C. orbiculare (from cucurbits), C. lindemuthianum, and C. trifolii being pathogenic only on cucurbits, green bean, and alfalfa, respectively. Consequently, distinct and fixed nucleotide, or genotypic (intron sequences and RFLPs) and phenotypic (host specificity) characteristics can be used to distinguish C. orbiculare, C. lindemuthianum, and C. trifolii from one another; therefore, they should be recognized as distinct species. This species delineation is consistent with the most current species concepts in fungi. More isolates and further characterization is needed to determine whether C. orbiculare from cocklebur and C. malvarum represent distinct species. RFLPs of the 900-bp intron may represent a relatively inexpensive, reliable, and useful diagnostic tool for general species differentiation in the genus Colletotrichum.     

植物激活蛋白对烟草花叶病毒RNA复制及外壳蛋白合成的抑制作用

研究了植物激活蛋白对烟草花叶病毒RNA及外壳蛋白的抑制作用。结果表明，烟草经植物激活蛋白处理后，植株体内烟草花叶病毒RNA含量比对照降低28％；用ELISA和Western方法检测烟草花叶病毒外壳蛋白的含量，处理分别比对照减少20．7％和25．0％。植物激活蛋白显著干扰烟草花叶病毒外壳蛋白的体外聚合过程，22—37％条件下其干扰作用达显著水平。