Natural infection of Chrysanthemum stunt viroid in dahlia plants

For the first time, Chrysanthemum stunt viroid (CSVd) was detected in commercial dahlia bulbs in Japan. CSVd was found in 77.2% of the tested plants (Dahlia spp.). In nucleotide sequence analysis, a CSVd variant was detected consisting of 354 nucleotides, which differed slightly from previously reported CSVd variants. The nucleotide sequence data reported is available in the DDBJ/EMBL/GenBank databases under accession number AB255879.     

Phylogeny of five predominant pospiviroid species in Belgium

In Belgium pospiviroids are routinely detected in various hosts. The most frequently found pospiviroids are: Citrus exocortis viroid (CEVd), Chrysanthemum stunt viroid (CSVd), Potato spindle tuber viroid (PSTVd), Tomato apical stunt viroid (TASVd) and Tomato chlorotic dwarf viroid (TCDVd). Apart from the high incidence of pospiviroids in latently-infected ornamentals, viroids have also been found in plants where they cause disease: PSTVd and TCDVd in tomatoes and CSVd in chrysanthemum. In order to gain more epidemiological data on these infections, this study has conducted phylogenetic analyses of Belgian isolates for each of these five pospiviroid species. PSTVd and CEVd-isolates show a clustering depending on host plant identity. This was not observed for TCDVd and TASVd. A very high degree of sequence similarity was noticeable for CSVd-isolates from various hosts. During the past decade, PSTVd and CSVd-infected mother plants have been systematically eradicated in Belgium after positive detection results, also when found in symptomless plants, leading to a decreased trend of these quarantine pests in the past few years. However, other non-quarantine pospiviroid species are still ubiquitously present in many ornamentals. Since these pospiviroids can be equally harmful to crops as the two quarantine pests PSTVd and CSVd, there is still a risk that transmission occurs from symptomless-infected ornamental plants to economically important crops in Belgium such as tomato, pepper and chrysanthemum.     

Genetic diversity and pathogenicity of potato spindle tuber viroid and chrysanthemum stunt viroid isolates in Russia

European Journal of Plant Pathology - To investigate the current status of viroid infection in potato fields in Russia, potato spindle tuber viroid (PSTVd) and chrysanthemum stunt viroid (CSVd)...     

Grassy Stunt,Ragged Stunt and Tungro Diseases of Rice in Indonesia

Abstract

Grassy stunt disease, ragged stunt virus and rice tungro virus, are among the most widespread and damaging rice diseases in Indonesia. Yield losses due to grassy stunt and the brown planthopper (Nilaparvata lugens) in the period 1974–77 were more than US$510 million. Ragged stunt virus is a new disease which is widespread in Indonesia and has been reported in several rice growing countries in Asia since 1977. Loss figures for ragged stunt are not available, however, individual farmers have suffered 100% yield loss in infected fields. Tungro and grassy stunt are controlled by resistant varieties but there are no commercially available varieties with resistance to ragged stunt.     

百合病毒病的发生与症状类型

百合病毒病症状类型可归纳为7种类型,轻花叶型(Mm),重花叶型(Sm),矮化型(Stu),丛簇矮化型(Rstu)。黄化矮化型(Ys),扁茎簇叶型(Fsbl),花变叶型(Phy),其中轻花叶型和重花叶型发生普遍,花变叶型出现较少。病害发生的轻重与种球种龄有关,种龄越大,发病越重。前茬种植百合的地块较种植小麦的地块发病重,低洼积水地发病重。不同百合品种对病毒病的抗性有差异。     

Nature and genetic relatedness of the mycoplasma-like organism causing rubus stunt in Europe

Cultivated red raspberries ( Rubus idaeus ), and wild blackberries ( R fruticosus, R. caesius , and Rubus hybrids) showing symptoms of rubus stunt were collected in Germany, France, and Italy, Ribosomal DNA of the mycoplasma-like organism (MLO) that causes rubus stunt was amplified by a polymerase chain reaction procedure and then digested with Atu I and Rsa I restriction endonucleases. All samples examined showed the same restriction profiles, which were similar to those of the MLOs inducing elm yellows and alder yellows. However, the rubus stunt MLO could be distinguished from the elm and alder MLOs by Southern blot analysis using DNA probes from a strain of the elm yellows MLO, A variability of the hybridization profiles, probably caused by restriction fragment length polymorphisms, was observed among the rubus stunt samples. From both rDNA restriction site and Southern blot analyses it can be concluded that the rubus stunt agent and the elm yellows and alder yellows MLOs are not identical but closely related and can be grouped in the same taxonomic cluster.     

基于TaqMan MGB探针的花生矮化病毒检测研究

花生矮化病毒(Peanut stunt virus,PSV)是我国进境检疫性有害生物。本研究根据该病毒不同分离株外壳蛋白基因(coat protein,CP)的保守序列,设计了特异性引物与TaqMan MGB荧光探针,建立了PSV的实时荧光RT-PCR检测方法。方法特异性研究表明,针对PSV的2个不同株系PSV-E和PSV-W,均能够得到典型扩增曲线,Ct值分别为20.10和21.22;而对于黄瓜花叶病毒、番茄不孕病毒、马铃薯Y病毒、菜豆荚斑驳病毒以及烟草环斑病毒等其他毒株则没有典型扩增曲线,也无Ct值。灵敏度比较发现,该方法比普通RT-PCR检测方法的灵敏度提高100倍,具有快速、灵敏和高特异性的优点,适合对PSV的检测。     

啤酒花矮化类病毒属属级寡核苷酸芯片筛查方法的建立

啤酒花矮化类病毒属是重要的植物类病毒属,目前尚无有效的筛查方法。通过对该属类病毒的核苷酸序列进行分析筛选,设计了8条用于该属类病毒筛查的属级特异性探针并制备了寡核苷酸芯片。应用啤酒花矮化类病毒标准样品对该芯片进行验证,结果表明所建立的属级芯片可以特异性检测啤酒花矮化类病毒,可检测到2ng/μL的总RNA。该芯片可用于啤酒花矮化类病毒属类病毒的筛查,为该属类病毒的检疫与防控提供技术支撑。     

应用RT-PCR方法检测水稻植株和介体昆虫体内的水稻齿叶矮缩病毒

 将生物学接种和RT-PCR检测水稻植株体内的水稻齿叶矮缩病毒的方法进行了比较,发现结果基本趋于一致,但总体上RT-PCR检测阳性率稍高于生物学接种的发病率。将生物学接种检测褐飞虱介体内水稻齿叶矮缩病毒方法与RT-PCR检测方法进行比较分析,发现RT-PCR方法可以检测单头褐飞虱体内的水稻齿叶矮缩病毒,具有很高的准确性和灵敏度。     

小麦丛矮病病原分子生物学鉴定

 2009年4月,从河北邯郸、邢台、保定麦田采集表现小麦丛矮病症状的植株,经室内人工饲养的无毒灰飞虱饲食传毒,可致健康小麦表现叶脉间褪绿,矮化,分蘖增多,整株黄化等典型丛矮病症状。根据已报道的小麦丛矮病毒(Wheat rosette stunt virus,WRSV)各基因片段和北方禾谷花叶病毒(Northern cereal mosaic virus,NCMV)基因组序列设计引物,利用反转录PCR (RT-PCR)方法,在上述3个标样中均检测到了NCMV,而未检测到WRSV。用RT-PCR扩增到NCMV全基因组序列,长度为13221nt,具有9个开放读框。核酸序列比对结果显示,该序列与日本报道的NCMV有93%的同源性;推导氨基酸序列与日本报道的NCMV有99%同源性;但核酸和氨基酸序列与WRSV无明显同源性。上述结果表明,从河北省小麦丛矮病株中检测到的病原是NCMV,首次通过分子生物学研究检测到中国小麦上感染有NCMV。     

一种引起花生严重矮化的黄瓜花叶病毒的(CMV)株系鉴定

 根据病毒生物学特性、颗粒形态和血清学性质,明确由山东泰安花生矮化病株上分离的一个病毒分离物为黄瓜花叶病毒(CMV)一个株系,并暂定名为CMV花生矮化株系(CMV-CS)。CMV-CS引起花生叶片显著变小,植株严重矮化以及蚜传效率低而不同于我国花生上流行比较普遍的CMV-CA株系。     

Maize Virus and Mycoplasma Diseases in Peru

Abstract

Surveys of maize for virus and mycoplasma-like diseases were conducted in Peru in 1978 and 1980. The following pathogens were discovered and identified: aphid-borne maize dwarf mosaic virus, beetle-borne maize chlorotic mottle virus, Peregrinus maidis-borne maize mosaic and maize stripe viruses, and Dalbulus maidis-borne maize rayado fino virus, corn stunt spiroplasma (CSS) and maize bushy stunt mycoplasma (MBSM). Some of these insect-borne pathogens are important constraints to maize production in Peru. Maize chlorotic mottle in the department of Lima and Cajamarca and ‘puca poncho’, a disease caused by CSS and/or MBSM, in Ayacucho significantly limit maize yields. As a result of these surveys, we believe that the principal maize virus and mycoplasma-like diseases in Peru have been identified, an accomplishment unrealised in other Latin American countries at present.     

First report of celery stunt anthracnose caused by <Emphasis Type="Italic">Colletotrichum simmondsii</Emphasis> in Japan

A new disease was found in Japan, on celery (Apium graveolens var. dulce) having severe chlorotic leaf spot, stunt, and dwarf with leaf curl. A spore suspension from the fungus isolated from affected plants induced identical symptoms 14 days after plants were sprayed. Identification and molecular characterization showed that the causal agent is Colletotrichum simmondsii. This report is the first of stunt anthracnose on celery caused by C. simmondsii. We propose the name “stunt anthracnose” for the new disease. Colletotrichum acutatum sensu lato, as reference pathogen of celery anthracnose, should be changed to C. fioriniae based on morphological and molecular characteristics.     

人工培养液在植原体昆虫介体筛选中的适用性

研究了一种人工培养液对各种常见的昆虫(主要是叶蝉)的亲和性和适用性.结果表明,该人工培养液适于本试验中大多数昆虫的人工饲养.用此方法,悬钩子广头叶蝉Macropsis.ftscula Zetterstedt和桤树广头叶蝉Oncopsis alniSchrank分别被再次确认为悬钩子矮化植原体和桤树黄化植原体的传播介体;田旋花麦蜡蝉Hyalesthes obsoletus Signoret再次被确认为葡萄黄化(stolbur)植原体的传播介体.此前,上述三种叶蝉已被传统的人工接种方法鉴定为相应植原体的传播介体.危害桤树的河谷树叶蝉Allygus modestus Scott尽管虫体DNA检测结果经常为阳性,但迄今其人工培养液的检测结果都是阴性,因此,我们认为河谷树叶蝉不是桤树黄化植原体的传播介体.Eppendorf管人工培养液饲养法不仅适用于潜在的植原体介体昆虫的筛选鉴定,而且可用于介体昆虫的生物防治研究.此外,本研究首次发现自然感染了葡萄上的一种被德国人称为"Vergi-lungskrankheit"植原体(AY组)的草地脊冠叶蝉Aprodes makarovi Zachvatkin.     

水稻锯齿叶矮缩病毒抗血清的制备及其应用

 采用人工接种发病的水稻锯齿叶矮缩病株茎叶的榨出液,以低速离心(4000rpm)结合聚乙二醇(PEG)的方法所得部分提纯的病毒,进行家兔免疫注射制备抗血清,结果以注射后3~4周的效价最高,可达1:4096,α-最适比值为1:13。应用这种方法制备成的水稻锯齿叶矮缩病毒(RRSV)的抗血清,进行了水稻矮缩病毒(RDV)病株与RRSV病株的鉴别诊断和RRSV毒源寄主的检测。结果证明,具卷叶、缺刻的RDV病株确非RRSV复合感染所致。毒源寄主测定表明,在供试的7种田间常见杂草中,有5种表现为阳性反应;经生物学回接证实,5种中有蟋蟀草、水蜈蚣和游草3种能成功地将RRSV传给水稻而引起发病。     

几种重要花生病毒研究新进展

 花生病毒病是影响花生生产的重要病害。近10年来,花生矮化病毒(PSV)、花生条纹病毒(PStV)和番茄斑萎病毒属(Tospovirus)病毒分子生物学研究进展,极大地丰富了对上述病毒基因组结构、遗传变异、进化的认识,以及病毒种、亚组和株系的科学划分。对PSV来说,提出了2个亚组的划分,而我国PSV株系血清学和RNA3全序列的分析,明确它们独自构成第3个新的亚组。对我国和东南亚国家PStV株系CP基因序列同源性的分析,说明在这些国家和地区PStV是单独进化的,形成不同症状类型的株系。Tospovirus属病毒分子生物学研究的深入使得该属病毒从番茄斑萎病毒(TSWV)1种增加到13种,其中侵染花生的病毒达5种,分布于不同的国家和地区。     

First report of Moroccan pepper virus on lisianthus (Eustoma grandiflorum) in Japan

In sap from plants of lisianthus (Eustoma grandiflorum) with necrotic stunt symptoms in Yamaguchi Prefecture in Japan, spherical particles with a diameter of about 30 nm were observed with transmission electron microscopy. We sequenced the complete genome of an isolate using the tombusvirus-specific primers and found that it shared about 96 % nucleotide identities with Moroccan pepper virus (MPV) in the genus Tombusvirus. The isolate reproduced necrotic stunt symptoms on lisianthus plants after mechanical inoculation. This is the first report of MPV on lisianthus in Japan.