Preliminary Studies on Black Spot of Globe Artichoke

Studies were conducted to determine the cause of an apparently new disorder of globe artichoke ( Cynara scotymus L.) characterised by a localised black necrosis in the receptacle of the flower buds. The effects of single and mixed infections by artichoke latent potyvirus (ALV) and broad bean wilt virus – French artichoke (BBWV-FA) in buds with necrosis of three globe artichoke cultivars were studied. Virus-free plants developed diseased buds irrespective of whether the plants were 1 or 2 years old, but the presence of ALV and/or BBWV-FA significantly increased black spot occurrence on 2-year-old plants. Virus effects were dependent on cultivar, cv. Capitan being less susceptible to virus infection than cvs Camus de Bretagne and Castel. The head size of the globe artichoke was found to be related to the rate of necrosis, with a higher incidence for terminal buds.
ALV and BBWV-FA did not cause the disorder but favour its development probably by weakening plants through increased leaf transpiration. The results are discussed in relation to a possible physiological disorder exacerbated by the presence of ALV and/or BBWV-FA.     

Studies on two Serologically Distinct Raspberry Ringspot Virus Strains from Artichoke

Two raspberry ringspot virus variants, RRV-T and RRV-G, found in artichoke of Turkish and Greek origin, were compared biologically (indexing), biochemically and serologically to two strains of the same virus, RRV-S and RRV-E originating from Scotland and England, respectively. Molecular weight values of protein and nucleic acid of RRV-T and RRV-G were in good agreement with those already known for RRV. RRV-T and RRV-G appeared serologically very similar to each other (serological differentiation index = 1) and well distinguishable from RRV-S and RRV-E (serological differentiation indices varying between 3 and 6). Phaseolus vulgaris cv. La Victoire, Ocimum basilicum cv. Foglia di Lattuga, Cucumis sativus cv. Delicatezza, and Cucurbita pepo cv. Zucchetta striata d'ltalia seemed herbaceous hosts useful for differentiating each strain from the others on symptomatological basis.     

Further Studies of a Simian Virus 40-Like Virus Isolated from Human Brain

A virus similar to simian virus 40 was reisolated from brain homogenates of a patient with progressive multifocal leukoencephalopathy onto cultures of human fetal brain cells.     

Artificial Induction and Evaluation of a Mild Isolate of Tomato Spotted Wilt Virus

A severe isolate (BL) of tomato spotted wilt virus (TSWV) that originated from Hawaii was treated with nitrous acid in an effort to obtain mild mutants. The standardized procedure used in mutation experiments was: extracting infected Gomphrena globosa L. leaf tissue in 0.01 M Na₂SO₃, 0.125 M sodium acetate and 0.4 M sodium nitrite at pH 5.5 and incubating the extract for 20 min at room temperature. The extract was inoculated to tobacco (Nicotiana tabacum L. cv. Havana 423) and local lesions were subsequently transferred to lettuce (Lactuca sativa L. cv. Minetto). One isolate (R27G) that incited mild symptoms in lettuce was obtained out of 868 local-lesion-transfers. Under greenhouse conditions, the isolate induced mild symptoms on tomato (Lycopersicon esculentum Mill.) but was severe on peppers (Capsicum annuum L.). The effect of the R27G isolate on growth of potted tomatoes kept outdoors was variable. In one trial, only 15 % of the fruit had symptoms versus 67 % in another trial. R27G fully protected Datura stramonium L. plants that were challenge inoculated with the severe parent BL isolate. Less effective cross protection was observed against a severe isolate from Oklahoma.     

侵染番茄的黄瓜花叶病毒（CMV）株系特性的比较研究

从山东省主要番茄种植区病毒样本中分离到111个黄瓜花叶病毒(CMV)分离物,根据病毒的寄主范围和症状,初步鉴定为三个株系:番茄蕨叶株系(CMV-ToF)、番茄花叶株系(CMV-ToM)和番茄轻花叶株系(CMV-ToL)。三株系除在生物学特性存在明显差异外,其病毒粒体形态大小,电泳迁移率,病毒外壳蛋白亚基分子量、核酸组分以及病毒粒体血清学特性亦存在差别。     

Effects of Artichoke Latent Virus Infection on the Production of Artichoke Heads

Virus-free and artichoke latent virus (ALV) infected plants of ‘Brindisino’ artichoke obtained by in vitro propagation, were studied over a period of three years to evaluate the effect of ALV infection on artichoke field performance and to determine the infection rate of healthy plants. ALV infection caused qualitative and quantitative changes ‘Brindisino’ artichoke such as leaf and bract discoloration, opening of head apex, delay of first harvest, shortening of head stalk, reduction of head width and a dramatic decrease of yield. Due to the high infection rate of healthy plants during the trial period, the differences in the production of heads between the two groups of plants decreased in the last year of experiment.     

Black Spot of Globe Artichoke: a Calcium-deficiency Disorder

Experiments were performed with field-grown artichoke ( Cynara scolymus L.) cv. Capitan to determine whether the black spot disorder was associated with calcium deficiency in receptacles. Ageing of the plants and size of heads contributed to lower Ca levels of receptacles. Receptacles with lower amounts of Ca were more affected by the disorder. Globe artichoke infection by artichoke latent virus (ALV) and/or broad bean wilt virus strain french artichoke (BBWV-FA) resulted in decreases in both the relative water content (RWC) of leaves and the Ca content of receptacles, and in increased black spot incidence. In addition, a wind-screen and an anti-trans-pirant spray (composed of a wax emulsion and a spreader/sticker surfactant) increased the RWC of leaves and bracts and the Ca content of receptacles, and also significantly reduced the incidence of necrosed buds.
These data support the view that Ca deficiency is involved in the occurrence of black spot disorder.     

刺槐上分离的花生矮化病毒的研究

刺槐花叶病是我国北方刺槐（Ｒｏｂｉｎｉａｐｓｅｕｄｏａｃａｃｉａ）常见病害。１９８７～１９９５年对河南、河北、山东和北京部分地区刺槐进行调查,刺槐花叶病发病率为４％～８７．５％。该病害主要特征是：叶片出现浅绿与绿色相间带有疱疹的花叶症状,叶缘波状扭...     

Further Studies on a Virus Causing a Green Mosaic Disease of Eggplant in Nigeria

A virus reported earlier to cause a green mosaic disease of eggplant in Nigeria was studied in more detail. Its filamentous particles with a normal length of 820 nm reacted in immunoelectron microscopical tests strongly with the homologous antiserum and less strongly with antisera to dioscorea green banding mosaic, groundnut eyespot, zucchini yellow mosaic viruses and to a tomato potyvirus isolate from Taiwan. No reactions were seen with antisera to 25 other potyviruses. Several new host plants were identified. Infected cells contained cylindrical inclusions with scrolls and short curved laminated aggregates and clusters of small vesicles with electron-dense content. Host range and serological reactivities differentiate the virus for which the name eggplant green mosaic virus is suggested from all potyviruses so far known.     

Recovery and Genetic Characterization of a West Nile Virus Isolate from China

West Nile virus(WNV) is an important neurotropic flavivirus that is widely distributed globally. WNV strain XJ11129 was first isolated in Xinjiang, China, and its genetic and biological characteristics remain largely unknown. In this study,phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1 a and shares high genetic identity with the highly pathogenic strain NY99. Then, the full-length genomic c DNA of XJ11129 was amplified and assembled using a modified Gibson assembly(GA) method. The virus(named r XJ11129) was successfully rescued in days following this method. Compared with other wild-type WNV isolates, r XJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo. In summary, the genomic and virulence phenotypes of r XJ11129 were characterized in vivo and in vitro, and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.     

蚕豆萎蔫病毒—新疆番茄分离株的鉴定

在新疆番茄斑驳病株上分离出一种球状病毒,回接到番茄上产生斑驳症状。病毒粒体为２０面体,平均直径２５ｎｍ。经汁液摩擦接种可感染昆诺阿藜、苋色藜、蚕豆、番茄等１８种植物,不感染菜豆、豇豆、豌豆、六叶茄、黄瓜等。可由桃蚜传毒。在琼脂双扩散试验中,能与蚕豆萎蔫病毒（ＢＢＷＶ）抗血清产生明显的沉淀线,与豇豆花叶病毒（ＣｐＭＶ）、黄瓜花叶病毒（ＣＭＶ）抗血清均不发生反应。纯化病毒紫外扫描呈典型的核蛋白吸收叫线,病毒衣壳蛋白由两种蛋白亚基构成,其分子量分别为４５９００和２０４００道尔顿,由１８种氨基酸约２５５个氨基酸残基组成。病毒核酸是双组份的,它们的分子量为１３２００００和２３４００００道尔顿。根据上述结果认为该病毒是蚕豆萎蔫病毒侵染番茄的一个株系。     

天津近郊番茄病毒类型的研究

应用ELISA间接法检测出天津近郊番茄上至少有9种病毒类型。且首次检测出国内在番茄上尚未报道的番茄黑环病毒(TBRV)、绒毛烟斑驳病毒(VTMoV)。经生物学测定还分离出番茄上表现枯斑型的86-125和在豇豆上产生大红斑的86-95-15均与13种抗血清呈阴性反应的杆状待测病毒。     

甜菜黑色焦枯病毒新疆分离物基因组RNA的序列分析及侵染性cDNA克隆构建

甜菜黑色焦枯病毒(Beet black scorch virus,BBSV)新疆分离物(BBSV-X)和宁夏分离物(BBSV-N)分别来自生态环境不同的新疆和宁夏的甜菜产区,自然条件下,BBSV-X含有卫星RNA,BBSV-N不含有卫星RNA。为明确二者的分子差异,以BBSV-X基因组RNA为模板,通过RT-PCR扩增获得了全长cDNA克隆。序列分析显示,BBSV-X基因组RNA全长为3 644个核苷酸,与以往报道的BBSV-N相同,且核苷酸序列一致性高达99.45%。除5′和3′非翻译区各有一个核苷酸发生变异外,核苷酸序列差异主要存在于ORF1通读区和ORF6,氨基酸序列差异仅存在于ORF1的通读区。构建获得了BBSV-X的侵染性cDNA克隆,用体外转录物定量接种了苋色藜(Chenopodiumamaranticolor)和豇豆(Vigna sinensis),结果显示BBSV-X与BBSV-N之间在致病性上存在一定的差异。     

韭菜病毒分离物初步鉴定

韭菜病毒分离物初步鉴定房德纯,王振东,佟成富,陆庆轩（沈阳农业大学植保系,沈阳１１０１６１）（辽宁省风沙地改良利用研究所,阜新１２３０００）（沈阳市园林科学研究院,沈阳１１００１５）关键词韭菜病毒病,毒原鉴定,韭菜萎缩病毒１９９３年在辽宁省阜新市韭菜...