Identification and transmission of Piper yellow mottle virus and Cucumber mosaic virus infecting black pepper (Piper nigrum) in Sri Lanka

Sri Lankan black pepper with symptoms of yellow mottle disease contained a mixture of viruses: Piper yellow mottle virus (PYMV) particles (30 × 130 nm), Cucumber mosaic virus (CMV, 30 nm diameter isometric particles), and unidentified, isometric virus-like particles (30 nm diameter). An effective purification procedure is described for PYMV. Immunosorbent and conventional electron microscopy successfully detected badnavirus particles only when at least partially purified extracts were used. PYMV was confirmed as the cause of the disease, with the other two viruses apparently playing no part in producing symptoms. PYMV was transmitted by grafting, by the insect vectors citrus mealy bug ( Planococcus citri ) and black pepper lace bug ( Diconocoris distanti ), but not by mechanical inoculation or through seeds. The CMV isolate was transmitted to indicator plants by mechanical inoculation and by the vector Aphis gossypii , but not by Myzus persicae ; but neither mechanical nor insect transmission of CMV to black pepper was successful. A sensitive polymerase chain reaction assay was developed to detect PYMV in black pepper.     

Little leaf disease of Piper nigrum in Sri Lanka

In recent years Black pepper ( Piper nigrum ) in Sri Lanka has become affected with'Little leaf'disease. The main symptoms are chlorosis of leaves, shortening of internodes, proliferation of branches, greening and enlargement of floral bracts. Detailed measurements within experimental plots of two improved varieties Panniyur 1 and Kuching, indicated that leaf size, the number of flowers per spike and berry weight were reduced on infected vines. Seeds from infected vines germinated less well than those from healthy vines. In a field trial, disease spread was similar in plots planted with pepper at different spacings and receiving different fertilizer treatments.     

A potyvirus isolated from solanaceous hosts

A potyvirus was isolated from Datura stramonium, Lycopersicon esculentum (tomato) and Solanum nigrum in the Yemen. It was transmitted mechanically and by Myzus persicae in a non-persistent manner. Its flexuous rod-shaped particles had a mean length of 719 nm and some of its pinwheel inclusion bodies in infected Nicotiana clevelandii leaves were unusual in that they were dichotomously branched. The virus infected various solanaceous species, but the symptoms it induced were distinct from those of pepper veinal mottle (PVMV) and potato Y viruses. Its particles were purified from N. glutinosa and their coat protein had an atypically high molecular mass a potyvirus of 41·5 kDa. They showed a distant serological relationship to those of PVMV and potato virus V in ISEM decoration tests, but did not react with antisera to particles of any other potyvirus tested. The virus has been tentatively named tomato mild mottle virus.     

Solanum nigrum: an indigenous weed reservoir for a tomato yellow leaf curl geminivirus in southern Spain

A tomato yellow leaf curl geminivirus (TYLCV-AL), was first identified in tomato plants in Almeria, southern Spain in 1992. This virus is transmitted by the tobacco whitefly, Bemisia tabaci (Gennadius), and is presently infecting tomato crops throughout the south eastern region of Spain. Solanum nigrum, collected from a field in south east Spain and exhibiting leaf curl symptoms, was squash blotted onto nylon membrane and gave a positive signal when hybridised to a TYLCV-Is DNA probe. Laboratory tests showed B. tabaci to transmit TYLCV-AL from infected tomato plants to S. nigrum seedlings. The virus could then be acquired by B. tabaci and transmitted back from infected S. nigrum plants to tomato, inducing typical TYLCV symptoms. These results indicate the importance of S. nigrum as a weed host/reservoir for a TYLCV and its possible role in the spread of this virus within Europe.     

Morphological and molecular characterization of Fusarium spp. associated with yellowing disease of black pepper (Piper nigrum L.) in Malaysia

Yellowing disease is one of the most important diseases of black pepper (Piper nigrum L.). To characterize the pathogen(s) responsible for yellowing disease of black pepper in Malaysia, 53 isolates of Fusarium were collected from the roots of diseased black pepper plants and from rhizosphere soils from major growing areas in Sarawak and Johor. A total of 34 isolates of F. solani and 19 isolates of F. proliferatum were obtained and identified based on morphological characteristics and molecular techniques. DNA sequencing of the internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA regions was conducted to identify Fusarium species. Nucleotide sequence analysis of the ITS regions revealed that this molecular technique enabled identification of Fusarium at the species level as F. solani and F. proliferatum. In a pathogenicity test on 3-month-old black pepper plants, F. solani was pathogenic, but F. proliferatum was not. On the basis of morphology, DNA sequences and pathogenicity of the fungal isolates from the diseased plants, we showed that yellowing disease on black pepper is caused by F. solani     

侵染我国芋的杆状DNA病毒分子鉴定及特异性检测

 采用已报道杆状DNA病毒属（Badnavirus）的通用检测引物BadnaFP/BadnaRP,从7份芋样品中扩增到 Badnavirus 病毒的RT/RNase H基因保守区域,获得12个克隆序列,长度为576 bp。序列分析结果显示,来自不同样品的克隆间核苷酸和氨基酸序列相似性分别为78.8%~99.5%和81.3 %~99.5%;来自同一样品扩增产物的克隆间在序列上也存在较大差异,核苷酸和氨基酸序列相似性分别为89.6%~100%和92.7%~100%。在系统进化树中,本研究所获序列与 Badnavirus病毒的亲缘关系相对较近,聚在同一簇,表明此病毒为 Badnavirus 属病毒,但与芋杆状病毒（Taro bacilliform virus,TaBV）序列相似性较低,核苷酸和氨基酸相似性分别为58.0%~62.2%和58.5%~64.1%,推测为杆状DNA病毒属的一个新种。根据所测定序列设计了用于该病毒检测的引物P197/P433,对51份芋样品检测结果表明,该引物可有效检测来源于我国芋的 Badnavirus 病毒。     

侵染甜椒的番茄黄化曲叶病毒的分子鉴定和全序列分析

<正>番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV)在世界范围内可危害多种作物,造成植株矮化、叶片皱缩变形、局部黄化等症状。该病毒自1964年首次报道以来已蔓延至世界多地。在我国2006年上海首次报道该病毒[1],随后江苏、山东、安徽、北京、河北、天津等地相继报道,危害严重。TYLCV为双生病毒科(Geminiviridae)菜豆金色花叶病毒属(Begomovirus)成员,基因组为单组     

番茄褐色皱果病毒SYBR GreenⅠ实时荧光RT-PCR检测方法的建立和应用

根据番茄褐色皱果病毒（tomato brown rugose fruit virus,ToBRFV）外壳蛋白（coat protein,CP）的保守基因序列设计1对特异性引物,建立了基于SYBR Green I的ToBRFV实时荧光RT-PCR检测方法,并对其进行了特异性、灵敏度检测,对自然感染ToBRFV的番茄、辣椒种子进行了检测验证。结果表明,构建的实时荧光RT-PCR检测ToBRFV阳性的番茄种子总RNA和重组质粒标准品的检测低限分别为0.2 ng/μL和50.0拷贝/μL,均为普通RT-PCR检测灵敏度的100倍;对番茄花叶病毒（tomato mosaic virus,ToMV）、番茄环斑病毒（tomato ringspot virus,ToRSV）、番茄黑环病毒（tomato black ring virus,TBRV）、番茄斑萎病毒（tomato spotted wilt virus,TSWV）、辣椒轻斑驳病毒（pepper mild mottle virus,PMMoV）、烟草花叶病毒（tobacco mosaic virus,TMV）和烟草环斑病毒（tobacco ri...     

Biochemical defense responses of black pepper (Piper nigrum L.) lines to Phytophthora capsici

A study on biochemical factors involved in black pepper defense response against Phytophthora capsici, was carried out in P. capsici susceptible (Sreekara) and resistant (04-P24, shows root resistance to the pathogen) black pepper lines. Seven important factors – change in membrane conductance, total phenols, orthodihydroxy (OD) phenols, lignin and defense related enzymes (peroxidase, β-1,3 glucanase and β-1,4 glucanase) – were studied under uninoculated and pathogen (P. capsici, isolate 06-04) inoculated condition to know the preformed and induced responses. The pathogen was inoculated (soil inoculation) and plants were observed for changes, at 24 h intervals for 10 days. On 8th day after inoculation symptoms started appearing on Sreekara and increased the severity till 10th day. Both root and stem samples were subjected for biochemical analysis. Of the factors analyzed, it was found that membrane conductance, OD phenol, lignin and peroxidase activity play significant role in root resistance to P. capsici in 04-P24. Light microscopy of the portion of root – where pathogen found attached – was also done.     

A new Badnavirus species detected in Bougainvillea in Brazil

Badnavirus in Bougainvillea spectabilis showing virus-like symptoms was identified by the presence of bacilliform particles, measuring 125–130 × 30–40 nm in leaf-dip preparations and by analysis of its putative open reading frame 3 sequence. The virus, tentatively named Bougainvillea bacilliform virus (BBV), had the highest identities (up to 60%) with Spiraea yellow leaf spot virus, Gooseberry vein banding associated virus, Taro bacilliform virus, and Citrus yellow mosaic virus. In phylogenetic analysis, BBV clustered with Badnavirus putative species. Attempts to transmit the virus to several hosts failed. This is the first report of a new Badnavirus detected in Bougainvillea.     

Genetic diversity and mixed infections of begomoviruses infecting tomato, pepper and cucurbit crops in Nicaragua

Begomoviruses were detected in Nicaraguan fields of tomato ( Lycopersicon esculentum ) and adjacently growing plants of pepper ( Capsicum annuum ), chilli pepper ( C . baccatum ), cushaw ( Cucurbita argyrosperma ) and Mexican fireplant ( Euphorbia heterophylla ) using polymerase chain reaction (PCR) and universal begomovirus primers. All tomato and Mexican fireplant plants showing symptoms were infected with begomoviruses, while only 30–46% of the pepper, chilli pepper and cushaw plants showing symptoms tested virus-positive. No begomoviruses were found in potato. The virus species were provisionally identified by sequencing 533 bp of the viral coat protein gene ( AV1 ). Tomato severe leaf curl virus (ToSLCV), Tomato leaf curl Sinaloa virus (ToLCSinV) and Pepper golden mosaic virus (PepGMV) were found to infect both tomato and pepper. A new provisional species designated Tomato leaf curl Las Playitas virus (ToLCLPV) was detected in a tomato plant. Squash yellow mottle virus (SYMoV) and PepGMV were found in cucurbits, the latter for the first time in this host. Euphorbia mosaic virus (EuMV) was detected in Mexican fireplant. Sequencing of a larger number of PCR-amplified clones from selected plants revealed intraspecific viral sequence variability, and also multiple begomovirus infections which could represent up to three species in a single tomato or cushaw plant. Phylogenetic grouping of virus sequences did not correlate with the host of origin.     

Broad bean wilt virus Causes Necrotic Symptoms and Generates Defective RNAs in Capsicum annuum

ABSTRACT A virus was isolated from hot pepper (Capsicum annuum cv. Hyang Chon) growing in Korea and displaying necrotic spots or streaks on leaves and stems followed by stunting and death of plants. Morphological and host range analyses of extracts from infected plants suggested that the causal agent of disease was a Broad bean wilt virus (BBWV), and the virus was tentatively named a Korean isolate of BBWV (BBWV-K). When the isolate was back-inoculated onto hot pepper plants, it induced symptoms similar to those of naturally infected hot pepper in the field. Two coat proteins (CPs) of 44 and 22 kDa, corresponding to a large CP and a small CP, respectively, were identified from the virus, and both reacted specifically with polyclonal antibody to BBWV 2. The complete nucleotide sequences of RNA 1 and RNA 2 of the isolate were determined from cDNA clones. The deduced amino acid sequence data from the putative proteins encoded by RNA 1 and 2 of the BBWV-K indicated a closer relationship with the isolates of BBWV 2 than BBWV 1. However, sequence comparison of the 5' noncoding regions of the viruses differentiates BBWV-K from other BBWV 2 isolates. Another distinctive feature of the BBWV-K is that it generates defective RNAs in hot pepper exhibiting necrotic symptoms, which is the first report of defective RNAs in the Fabavirus genera of BBWVs.     

侵染假酸浆的泰国番茄黄化曲叶病毒全基因组结构特征

为明确假酸浆Nicandra physalodes叶片黄化、皱缩症状是否由菜豆金色花叶病毒属病毒侵染引起,本研究利用分子检测方法和生物信息学技术鉴定了假酸浆样品中的病毒种类。从采集的病样中克隆并获得了2条菜豆金色花叶病毒属病毒DNA-A全序列和1条beta卫星全序列,经全序列分析发现,该双生病毒的两条DNA-A全序列与泰国番茄黄化曲叶病毒(tomato yellow leaf curl Thailand virus, TYLCTHV)云南分离物TYLCTHV-YN1732一致性最高,达99.3%,亲缘关系较近;beta卫星的全序列与云南番茄曲叶beta卫星(tomato leaf curl Yunnan betasatellite, TLCYnB)的分离物YN5230一致性最高,达99.3%,亲缘关系较近。重组分析显示,假酸浆上分离的TYLCTHV-YN5735-12是一个重组病毒,有两个重组事件,一个主要发生在AV1的编码区,由中国番茄黄化曲叶病毒(tomato yellow leaf curl China virus, TYLCCNV)和广西大戟曲叶病毒(euphorbia lea...     

番茄细菌性斑点病病原菌鉴定

 1998~1999年在吉林省、辽宁省、黑龙江省等地的大棚番茄上发现一种番茄病害,并从其病叶、病茎杆上分离得到了23个细菌菌株。接种番茄幼苗上,发病症状与自然发病症状完全一致,并从接种病株上重新分离到此病原细菌。各菌株致病力无明显的差异。经革兰氏染色反应、菌体形态、培养性状、生理生化反应、G+C mol%等鉴定,确认该病原菌为丁香假单胞杆菌番茄致病变种(Pseudomonas syringae pv.tomato(Okabe)Young,Dye&Wilkie)。该病菌引起番茄细菌性斑点病(又称叶斑病)。病菌除侵染番茄外,尚能侵染茄子、辣椒、龙葵、白花曼陀罗和毛曼陀罗。该病害尚属我国大陆首次报道。     

Responses of white yam (Dioscorea rotundata) cultivars to inoculation with three viruses

The responses of 24 white yam ( Dioscorea rotundata ) cultivars to mechanical and vector transmission with each of three viruses infecting yams were assessed through enzyme-linked immunosorbent assay (ELISA) and symptom development. The viruses were Dioscorea alata virus (DAV), genus Potyvirus ; Dioscorea alata bacilliform virus (DaBV), genus Badnavirus ; and Cucumber mosaic virus (CMV), genus Cucumovirus . Only TDr 95-128, a landrace cultivar from Nigeria, developed symptoms of infection with CMV and DaBV following mechanical and vector transmission, respectively. PAS-ELISA showed that nine genotypes remained uninfected by DAV and 11 were uninfected by CMV or DaBV. Genotypes TDr 747 and TDr 1640 both showed resistance to all three viruses.     

云南水稻上检测到南方水稻黑条矮缩病毒

南方水稻黑条矮缩病(Southern rice black streaked dwarf disease)是我国南方稻区一种新的水稻病毒病害.自2001年在广东省阳西县首次发现以来,该病危害范围逐年扩大,2009年我国湖南、江西、广东、广西、海南、浙江、福建、湖北和安徽9个水稻主产省(区)及越南北部19个省发病面积约33.33万hm2,基本绝收面积0.67万hm2[1,2],对水稻生产威胁巨大.     

从进境印度尼西亚辣椒种子中截获番茄环斑病毒

本文利用DAS-ELISA方法从印度尼西亚进境的辣椒种子中初步筛选出疑似感染有番茄环斑病毒(ToRSV)的样品,利用IC-RT-PCR(immune capture RT-PCR)扩增特异性片段,进而对扩增的PCR产物进行了测序和序列比对,确认我们在进境的辣椒种子中检出了我国关注的检疫性有害生物——番茄环斑病毒。此前该病毒未有在印度尼西亚辣椒上危害的报道,是系统内首次在蔬菜种子上截获该病毒。     

甘蔗病毒病及其防治研究进展

甘蔗是最重要的糖料作物,由于其栽培过程中采用种茎无性繁殖,病毒病发生逐年加重.已知侵染甘蔗的病毒种类有甘蔗花叶病毒(Sugarcane mosaic virus,SCMV)、高粱花叶病毒(Sorghummosaic virus,SrMV)、甘蔗线条花叶病毒(Sugarcane streakmosaic virus,SCSMV)、甘蔗黄叶病毒(Sugarcane yellow leaf virus,SCYLV)、甘蔗斐济病病毒(Sugarcane Fiji disease virus,SFDV)、甘蔗线.条病毒(Sugarcane streak virus,SSV)和甘蔗杆状病毒(Sugarcane bacilliform virus,SCBV).文中简要介绍上述几种病毒的基本特性及其所致病害的发生特点,对目前甘蔗病毒病防治技术进行了评述,提出了我国甘蔗病毒研究中需要关注的若干问题.