首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Using ELISA to determine whether cowpea mild mottle virus (CMMV) was present in soybean and groundnut seeds, the virus was not detected in 4144 seeds harvested from seven CMMV-infected soybean genotypes and in 214 seeds collected from CMMV-infected groundnut plants (cv. Gajah). These results, together with those of other researchers, suggest that, under the conditions tested, CMMV is not transmitted by seed. This in contrast to what is generally accepted and published in reviews.  相似文献   

2.
In four neighbouring regions of southern Italy, Basilicata, Campania, Apulia and Calabria, pepper and zucchini plants showing Phytophthora blight symptoms, tomato plants with either late blight or buckeye rot symptoms, plants of strawberry showing crown rot symptoms and declining clementine trees with root and fruit rot were examined for Phytophthora infections by means of polymerase chain reaction (PCR) assays, using primers directed to nuclear ribosomal DNA (rDNA) repeat sequences. All diseased plants and trees examined tested positive. The detected fungal-like organisms were differentiated and characterized on the basis of primer specificity as well as through extensive restriction fragment length polymorphism (RFLP) and sequence analysis of PCR-amplified rDNA. Phytophthora capsici was identified in diseased pepper and zucchini plants, P. infestans was identified in tomato with late blight symptoms whereas buckeye rot-affected tomatoes and diseased strawberry plants proved to be infected by P. nicotianae and P. cactorum, respectively. Declining clementine trees were infected with P. citrophthora and P. nicotianae in about the same proportion. Also, thirty-one pure culture-maintained isolates of Phytophthora which had previously been identified in southern Italy by traditional methods but were never examined molecularly, were examined by RFLP and sequence analysis of PCR-amplified nuclear rDNA. Among these, an isolate from gerbera which had previously been identified by traditional methods only at genus level, was assigned to P. tentaculata. For the remaining pure culture-maintained isolates examined, the molecular identification data obtained corresponded with those delineated by traditional methods. Most of the diseases examined were already known to occur in southern Italy but the pathogens were molecularly detected and fully characterized at nuclear rDNA repeat level only from other geographic areas, very often outside Italy. A new disease to southern Italy was the Phytophthora blight of zucchini. This is also the first report on the presence and molecular identification of P. tentaculata from Italy.  相似文献   

3.
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.  相似文献   

4.
An investigation of the biological properties of the virus causing tomato yellow leaf curl disease in Tanzania was initiated to compare it with other known tomato yellow leaf curl viruses. Properties relating to acquisition and inoculation feeding time, persistence, mechanical inoculation, seed transmission and host range were studied. Results obtained indicate that the virus was transmitted persistently byBemisia tabaci Genn., but it was not mechanically, sap- or seed-transmissible. Minimum acquisition and inoculation feeding time was 30 min.Capsicum annuum, Datura stramonium, Nicotiana glutinosa, N. tabacum andLycopersicon esculentum were found to be hosts of the virus among the plant species tested, whereasPhaseolus vulgaris was not. It is concluded that the properties of the agent causing yellow leaf curl symptoms in tomato plants from different regions in Tanzania are similar to those ofTomato yellow leaf curl Sardinia virus species studied elsewhere. http://www.phytoparasitica.org posting Feb. 20, 2003.  相似文献   

5.
2019年山东种植的西葫芦上广泛发生病毒病,症状与之前常发症状有差异,发病植株叶片向下卷曲、黄化,植株矮化。为明确引起此次西葫芦病毒病的病原,我们以田间采集的10份西葫芦病叶为材料,进行PCR扩增并测序。测序结果显示扩增片段核苷酸序列与我国广东的中国南瓜曲叶病毒(SLCCNV)南瓜分离物(MW389917.1)一致性最高。根据同源序列设计引物,经PCR扩增获得SLCCNV全长序列,DNA-A 全长为2 730 bp(OM692270.1)、DNA-B 全长为2 711 bp(OM692269.1),经序列比对发现DNA-A序列与已登录的SLCCNV一致性为89.65%~99.42%,其中与我国广东的SLCCNV-GDHY南瓜分离物(MW389917.1)一致性最高,为99.42%;DNA-B序列与已登录的SLCCNV一致性范围为81.82%~97.29%,其中与我国广东的SLCCNV-GDHY南瓜分离物(MW389918.1)一致性最高,为97.29%。因此推测引发山东西葫芦病毒病的病原物是SLCCNV,由于该病毒是在山东西葫芦上首次发现,将其命名为SLCCNV-SD。前人已报道SLCCNV可侵染南瓜、甜瓜、烟草、番茄等作物,但SLCCNV可侵染西葫芦在国内未见报道。  相似文献   

6.
This paper reviews the contribution of vector activity and plant age to virus spread in potato crops. Determining which aphid species are vectors is particularly important for timing haulm destruction to minimize tuber infection by potato virus Y (PVY). Alate aphids of more than 30 species transmit PVY, and aphids such asRhopalosiphum padi, that migrate in large numbers before flights of the more efficient vector,Myzus persicae, appear to be important vectors. Differences in methodology, aphid biotypes and virus strains prevent direct comparisons between estimates of vector efficiencies obtained for aphids in different countries in north western Europe. M. persicae is also the most efficient vector of potato leafroll virus (PLRV), but some clones ofMacrosiphum euphorbiae transmit PLRV efficiently toNicotiana clevelandii and potato test plants. The removal of infected plants early in the season prevents the spread of PLRV in cool regions with limited vector activity. The proportion of aphids acquiring PLRV from infected potato plants decreases with plant age, and healthy potato plants are more resistant to infection later in the season. Severe symptoms of secondary leafroll developed on progeny plants of cv. Maris Piper derived from mother plants inoculated with PLRV in June or July of the previous year. Progeny plants derived from mother plants inoculated in August showed only mild symptoms, but the concentration of PLRV in these plants was as high as that in the plants with severe symptoms.  相似文献   

7.
Phosphites (Phi) are alkali metal salts of phosphorous acid, with the ability to protect plants against different pathogens. In this research, the effect of Phi applied to potato plants on severity of three important potato diseases in Argentina was assessed. Seed tubers and foliage of potato cvs Shepody and Kennebec were treated with Phi to assess effects on resistance against Phytophthora infestans, Fusarium solani and Rhizoctonia solani. Protection resulting from Phi treatment in seed tubers was high against P. infestans, intermediate against F. solani, and low against R. solani. In addition, seed tubers treated with calcium or potassium phosphites (CaPhi and KPhi, respectively) at 1% of commercial product emerged earlier than untreated ones. When Phi were foliarly applied two or four times at different doses, high levels of protection against P. infestans were achieved in both cultivars. Higher protection was observed in Kennebec when CaPhi was applied, while in Shepody this was true for KPhi. Expression of β-1,3-glucanases was induced at different times after treatment but no correlation between β-1,3-glucanases expression and foliar protection level was found. On the other hand, Phi positive protection effects did not produce negative effects in plant growth. Leaves from CaPhi-treated plants showed a darker green colour than leaves from control plants; also an increase in Rubisco protein and a delay in crop senescence was observed.  相似文献   

8.
Aubian wheat mosaic virus, a new soil-borne wheat virus emerging in France   总被引:1,自引:0,他引:1  
The properties of Aubian wheat mosaic virus (AWMV), a new soil-borne wheat virus in France, were investigated. Symptoms include foliar mosaic and severe stunting of winter wheat. The vector of the disease is unknown but the plants infected carry Polymyxa graminis in the roots. AWMV was transmitted mechanically to wheat and to two dicotyledoneous species: Lactuca sativa and Vicia faba. This virus was transmitted by seed to three winter wheat cultivars tested. Purified preparations contained rod-shaped particles with a variable length of 150–700 nm. Certain particles are very long and appear flexible. Antiserum raised against AWMV reacted specifically with AWMV in both indirect and direct enzyme-linked immunosorbent assays (ELISA). The incidence of AWMV in 26 winter wheat cultivars was investigated in the field during the growing season of 1999–2000. AWMV was detected in roots and shoots of all cultivars regardless of the symptoms. Twelve virus species belonging to the genera Benyvirus, Bymovirus, Furovirus, Pecluvirus and Pomovirus did not react with the AWMV antisera. A new tubular virus described in winter wheat in Bedfordshire in England reacted strongly with AWMV in ELISA. It is concluded that AWMV and probably the Bedford-virus constitute a previously undescribed tubular virus biologically and serologically distinct from other soil-borne viruses of wheat.  相似文献   

9.
To clarify the mechanism of seed transmission of Pepper mild mottle virus (PMMoV), the virus was immunolocalized in Capsicum annuum seeds using fluorescence microscopy. Two distinct patterns were observed: In the first, PMMoV was present in the epidermis and parenchyma but not in the endosperm or embryo; in the second, the virus was restricted to the surface of the epidermis and parenchyma. These findings shed light on the fundamental mechanisms of seed transmission of tobamoviruses and may aid in the design of new methods to prevent the spread of seedborne virus diseases.  相似文献   

10.
 西瓜花叶病毒(watermelon mosaic virus,WMV)是危害我国葫芦科作物生产的重要病原。培育和种植抗病品种是防治病毒病最经济有效的措施。本研究利用RT-PCR和血清学方法在表现环斑症状的西葫芦果实上检测到WMV,未检测到番木瓜环斑病毒(papaya ringspot virus,PRSV)。接种WMV侵染性克隆到西葫芦品种绿源冬宝,果实表面产生环斑症状,表明WMV是引起西葫芦果实表面环斑症状的重要病原。利用间接ELISA方法对山东泰安的西瓜、黄瓜、甜瓜、西葫芦和南瓜等46个样品检测发现33个样品表现WMV血清学阳性(检出率71.74%),薛庄采集的带有环斑症状的西葫芦均检测到WMV。对山东省81份葫芦科作物种质资源抗WMV鉴定发现西葫芦品种万盛丰宝、盛丰金珠表现中抗(MR);西瓜品种绿宝新秀和浪潮一号表现中抗(MR);甜瓜品种黄皮面瓜表现抗病(R);黄瓜品种星君贝贝表现中抗(MR);南瓜品种爱维80南瓜表现高抗(HR),蜜本南瓜、传统蜜本南瓜、七叶早南瓜、玲珑二号和绿贝贝迷你南瓜等5个品种表现抗病(R);瓠瓜品种均表现为感病(S)。研究结果对合理布局葫芦科作物品种防控WMV具有重要意义。  相似文献   

11.
12.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

13.
Seed transmission of two pathogroups of rice yellow mottle virus from Soudano-Sahelian areas of West Africa was studied in several rice genotypes. The virus was detected by enzyme-linked immunosorbent assay and the highly susceptible rice variety BG 90-2 was used for infectivity assays. In most of the rice genotypes studied (17 out of 21), rice yellow mottle virus was detected in all seed parts including glumella, endosperm and embryo at a rate ranging from 65 to 100%. Nevertheless, no seed-borne infection was found. Infectivity of the virus decreased throughout the process of seed formation suggesting inactivation of the virus as a result of seed maturation and desiccation. It was concluded that rice yellow mottle epidemics do not develop from seed-borne infections in rice seeds.  相似文献   

14.
为明确广谱性抗病毒基因—酵母pac1基因对葡萄B病毒(Grapevine virus B,GVB)的抗性效果,通过农杆菌介导的遗传转化,将pac1基因导入西方烟37B,对转基因植株进行PCR鉴定及Southern blot分析,通过病毒摩擦接种观察症状以及实时荧光定量RT-PCR检测植株体内病毒含量,并对转基因植株抗病性进行初步鉴定。结果表明,目的基因pac1成功导入并整合至西方烟37B基因组,共获得10个转基因株系。不同株系的T1代烟草中阳性植株比例为16.7%~72.7%,表明目的基因可成功遗传到子代。接种病毒后转基因植株普遍延迟发病,但后期症状与非转基因对照相似,其中仅1个转基因株系B6具有不表现典型症状等抗性反应。接种植株病毒含量检测中,所有转基因植株均检测到病毒存在,但表现为抗病的B6株系中病毒含量显著低于非转基因对照,表明该转基因植株虽不能完全抵抗GVB侵染,但对GVB具有耐病性。  相似文献   

15.
Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004–2006, with disease incidence of 2–30% (10% in average). In addition to typical wilting symptoms on the foliage, in cases of severe infection, progeny tubers were rotten in the soil. Six strains were characterised by biochemical, serological and PCR-amplification. All tests verified the strains as Dickeya sp. The rep-PCR and the biochemical assays showed that the strains isolated from blackleg diseased plants in Israel were very similar, if not identical to strains isolated from Dutch seed potatoes, suggesting that the infection in Israel originated from the Dutch seed. The strains were distantly related to D. dianthicola strains, typically found in potatoes in Western Europe, and were similar to biovar 3 D. dadanti or D. zeae. This is the first time that the presence of biovar 3 strains in potato in the Netherlands is described. One of the strains was used for pathogenicity assays on potato cvs Nicola and Mondial. Symptoms appeared 2 to 3 days after stem inoculation, and 7 to 10 days after soil inoculation. The control plants treated with water, or plants inoculated with Pectobacterium carotovorum, did not develop any symptoms with either method of inoculation. The identity of Dickeya sp. and P. carotovorum re-isolated from inoculated plants was confirmed by PCR and ELISA.  相似文献   

16.
番茄褪绿病毒tomato chlorosis virus (ToCV)是我国蔬菜生产的重要新发病毒,其寄主范围逐年扩大。2019年10月项目组在山东寿光西葫芦温室调查时发现部分叶片呈现黄化、脉间褪绿,类似于ToCV侵染症状,并伴有烟粉虱发生。利用特异性引物检测发现,扩增的目的片段与GenBank中登录的侵染番茄的ToCV基因序列(登录号:KC887998.1)同源性高达99.58%,充分说明西葫芦植株已被ToCV侵染。通过对病毒病发生规律和烟粉虱虫口数量调查发现,西葫芦定植后1个月表现侵染症状的植株为2.0%,定植后2个月达到4.2%,定植后4个月后高达68.2%,病毒发生呈指数增长,而烟粉虱虫口数量却维持较低密度。从济南和德州采集的西葫芦疑似病叶和烟粉虱中也检出ToCV病毒,说明该病毒可能已经在山东省设施西葫芦主要种植区普遍发生,并经烟粉虱广泛传播,需引起高度重视。  相似文献   

17.
New mite-borne virus isolates from rakkyo,shallot and wild leek species   总被引:2,自引:0,他引:2  
Flexuous viruses were transmitted from rakkyo (Allium chinense) and wild leek species (especiallyA. commutatum) to plants of crow garlic (A. vineale), by transfer of dry bulb mites. By electron microscope decoration tests using three antisera and by inoculations onto test plants, it was concluded that from each of the two natural host species at least two viruses were isolated. The viruses from wild leeks are both pathogenic onAllium spp. and may be of economic importance. Decoration tests on a virus mixture from shallot obtained earlier, revealed another new mite-borne virus in this species. The mite-borne viruses ofAllium spp. appear to be very common; they are largely diverse and their identification remains difficult.  相似文献   

18.
An indexing system for detectingTomato mosaic virus (ToMV) in commercial tomato seed lots is described. Factors associated with the procedure were analyzed and the following standard two-step working scheme is proposed: (i) mass screening by ELISA for the presence of the virus; (ii) evaluation of virus infectivity within the infested seed lots. A threshold of 10 ng ml−1 was determined for detection of purified ToMV by either ELISA or plant inoculation.Nicotiana tabacum cv. Xanthi NN was found to be a highly sensitive local lesion assay plant for the detection of ToMV. A positive ELISA threshold (1.3 times above the non-specific background) was set for seed samples taken from commercial seed lots by testing the same samples by both ELISA and a bioassay. http://www.phytoparasitica.org posting July 14, 2004.  相似文献   

19.
The coat protein gene of the nematode non-transmissible, SP5 isolate of pea early-browning tobravius was replaced with that of the highly nematode transmissible, PPK20 isolate of tobacco rattle tobravirus. Plants were infected with the recombinant virus when mechanically inoculated and the virus invaded the plants systemically. However, although the PPK20 isolate of TRV was transmitted by nematodes from these plants, the recombinant virus was not transmitted. Therefore, the virus coat protein is not the exclusive determinant of nematode transmission.  相似文献   

20.
Tomato leaf curl New Delhi virus (ToLCNDV; family Geminiviridae, genus Begomovirus) is an emerging virus in horticulture crops in Asia, and has recently been introduced in Spain, Tunisia and Italy. No betasatellite DNA was detected in infected tomato and zucchini squash samples from Spain, and agroinoculated viral DNA‐A and DNA‐B were sufficient to reproduce symptoms in plants of both crop species. Infected tomato and zucchini squash plants also served as inoculum sources for efficient transmission either mechanically or using Bemisia tabaci whiteflies. Cucumber, melon, watermelon, zucchini squash, tomato, eggplant and pepper, but not common bean, were readily infected using viruliferous whiteflies and expressed symptoms 8–15 days post‐inoculation. New full‐length sequences from zucchini squash and tomato indicated a high genetic homogeneity (>99% sequence identity) in the ToLCNDV populations in Spain, pointing to a single recent introduction event.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号