侵染西番莲属(Passiflora)植物的五个黄瓜花叶病毒分离物的特性比较

从紫果西番莲(Passiflora edulis)、杂交种西番莲(P. edulis X P.edulis var. flavicarpa)、黄果西番莲(P.edulis var. flavicarpa)、转心莲(P.caerulea)及龙珠果(P.foetida)分离到的5个黄瓜花叶病毒(CMV)分离物(PE、PE2、PEf、PC、PF)所作的生物学性质、理化特性和血清学关系的比较研究结果表明,5个分离物在寄主反应及血清学性质上存在不同,而在病毒粒体形态、体外抗性、蚜虫传毒和病毒外壳蛋白分子量方面无明显差异.根据5个分离物的寄主反应和血清学关系,可将其区分为CMV的两个亚组,其中PE、PE2、PC和PF属CMV亚组I,PEf属CMV亚组II.     

西安地区瓜类病毒病的鉴定及防治

西安地区195个瓜类病毒病样的鉴定结果表明,各种瓜类上的病毒为甜瓜花叶病毒(MMV)和黄瓜花叶病毒(CMV)两种。西葫芦、笋瓜、甜瓜、南瓜以及黄瓜上,以引致花叶的MMV为主(一般占90％以上),其次是黄化皱缩病状的CMV。西瓜只有MMV;冬瓜和丝瓜则为CMV。甜瓜和西葫芦上还分离到CMV的一个新株系,西瓜可以作为以上两种病毒的鉴别寄主。     

黄瓜花叶病毒致病性研究进展

黄瓜花叶病毒(Cucumber mosaic virus,CMV)属于正义单链RNA病毒,寄主广泛,危害严重,是当前最具影响力的植物病毒之一,也是世界公认的重要植物病害。CMV自1916年报道以来,国内外学者从病毒基因、基因编码产物以及与寄主相互作用等多个方面展开了大量研究。随着高通量测序技术与蛋白质组学技术的发展,病毒相关致病机制也取得突破性进展。介绍了CMV编码蛋白,CMV相关的卫星RNA以及寄主因子在CMV侵染植物后的症状发展过程中的作用,并对今后的CMV致病性研究进行了讨论,旨为CMV的相关研究提供参考。     

侵染天南星科植物病毒的分子鉴定及其生态学研究

通过病毒粒子部分提纯和形态学观察,发现侵染我国南方天南星科植物的病毒主要有线状和球状两种形态．经病毒基因组序列分析确定线状病毒为芋花叶病毒(DsMV);经血清学反应和序列分析确定球状病毒为黄瓜花叶病毒(CMV)．CMV CP基因序列同源性分析的结果表明,侵染天南星科的CMV是相对独立的种内变异类型,归属于亚组L同时,CMV存在对天南星科植物的适应性变异．对采自我国海南、湖南、浙江、上海等地的126个天南星科植物样品进行RNA核酸斑点杂交检测,获得病毒检测结果。海南省样品DsMV的检出率为73．3％,CMV的检出率为46．7％;湖南省样品DsMV的检出率为100％,CMV的检出率为38.5％;浙江省样品DsMV的检出率为93．0％,CMV的检出率为7．0％;上海市样品DsMV的检出率为100％,尚没有检测到CMV,首次证实了自然条件下CMV作为天南星科植物主要病毒的存在,在我国南方地区,该病毒对天南星科植物的自然侵染受到气候、季节和寄主等生态因子的影响。DsMV则在天南星科植物上普遍存在。     

从烟草上分离的黄瓜花叶病毒

黄瓜花叶病毒(CMV)危害烟草已成为烟区严重病害之一,如山东烟区CMV引起的烟草病毒病发病率达50%以上。CMV在福建烟区的发病率也达15～30%。上述调查系根据烟草田间症状表现以及温室内不同鉴别寄主的反应和抗性测定得到。为了进一步     

黄瓜花叶病毒致弱卫星RNA对辅助病毒含量的影响

为研究黄瓜花叶病毒(CMV)弱病毒株的基因组RNA和卫星RNA的含量变化,将一个卫星RNA介导的CMV弱病毒株NDM-1与CMV强毒株在4种寄主系统上进行对照实验.采用RNA点杂交方法,检测从早期接种病毒到大田释放阶段（病毒接种后5到40天）,寄主植物叶组织中的基因组RNA和卫星RNA的相对含量变化.结果显示：弱病毒株NDM-1基因组RNA和卫星RNA负荷量具有寄主效应和时间效应,趋势一致但程度不同.它们在番茄上的变化规律不同于其他寄主而且病毒的致弱效果最明显：在接种后的5～10天 (生产上接种育苗的保护期) ,基因组RNA和卫星RNA相对含量上升,到40天(大田释放期) 时回落至最低.比较NDM-1于不同时间在各寄主上的卫星RNA和基因组RNA的相对比值：在40天时,寄主番茄上的相对比值达15.8,与在其他寄主上和其他时间段比较均有显著差异,即此时卫星RNA达到含量优势.说明弱病毒NDM-1在番茄上的致弱机制为:卫星RNA的大量复制对CMV基因组RNA产生抑制作用.此弱病毒株在烟草和心叶烟中的变化规律基本一致.     

保存CMV毒源的试管烟苗方法

黄瓜花叶病毒（简称CMV）有极其广泛的天然寄主，能侵染75科近700种植物，迄今还缺少有效的防治方法，有植物界的“流感’与“癌症”之称。烟草受害尤重，一股流行年份烟草产值下降25～40％，严重的达50％以上乃至绝收。为此众多生物技术工作者分别从不同角度开展了CMV的研究。     

从烟草上分离的黄瓜花叶病毒

黄瓜花叶病毒(CMV)危害烟草已成为烟区严重病害之一,如山东烟区CMV 引起的烟草病毒病发病率达50%以上。GMV 在福建烟区的发病率也达15～30%。上述调查系根据烟草田间症状表现以及温室内不同鉴别寄主的反应和抗性测定得到。为了进一步研究与肯定CMV 引起的烟草病毒病,有必要由病株分离病毒和进行电子显微镜观察鉴定。     

浙江油菜花叶病毒类型研究

浙江各地引起油菜花叶病的病毒类型有芜菁花叶病毒(TpMV)、黄瓜花叶病毒(CMV)、菸花叶病毒(TMV)及芜菁花叶病毒和黄瓜花叶病毒的复合病(TpMV+cMV)。芜菁花叶病毒有TpMV98。和TpMV98 两个毒株,主要区别： TpMV98不侵染心叶菸,TpMV58 侵染心叶菸引起的系统性枯斑和系统性环斑能随环境的影响相互转变。黄瓜花叶病毒有CMV69和CMV72 两个毒株,主要区别：CMV69,回接不上本地油菜,CMV72 能回接上本地油菜。菸花叶病毒毒株(TMV45)侵染多种十字花科植物,在胜利油菜上引起系统花叶,在苋桥红萝卜上是无病状带毒,在农特400号菸上引起局部枯斑。TPMV98和CMV69 或CMV72 形成复合病,可以汁液接种分离,再混合再分离。根据采集样品按类型和毒株来看,浙江大田油菜花叶病,绝大多数是芜菁花叶病毒类型中的TpMV98毒株,复合病和黄瓜花叶病毒分布也相当广。辣根(Cochlearia armoracia L.)上所采的四个样品均属芜菩花叶病毒中侵染心叶菸的TpMV58毒株,辣根的宿根可以保存病毒,可能是这一毒株的越夏寄主之一。     

西葫芦黄化皱缩病CMV毒株的提纯及其理化性质的研究

西安西葫芦黄化皱缩病的黄瓜花叶病毒(CMV)毒株,以普通烟为繁殖寄主,将病叶组织经柠檬酸缓冲液匀浆抽提,PEG沉淀,三次差速离心循环,可成功地得到病毒提纯制备物,每公斤病叶组织的病毒产量为300—800 mg。电镜观察到直径约30nm的等轴病毒颗粒,病毒的沉降常数So20w=98,外壳蛋白亚基分子量为2．62×104道尔顿。     

Further studies on seed transmission in the ecology of some aphid-transmitted viruses

A small proportion (1–4%) of the seeds of Stellaria media extracted from fallow soil from three widely separated areas contained cucumber mosaic virus (CMV). S. media seeds buried for 21 months produced 5 % infected seedlings. S. media plants from Britain, N. America and Australia were least severely affected by the CMV strain obtained from their country of origin and showed more severe reactions when infected with two alien strains. Several weed species were experimentally infected with lettuce mosaic, turnip mosaic and cauliflower mosaic viruses but, although virus was detected in the seeds of some species, it was not transmitted to any of their seedlings.     

Studies on the seed transmission of cucumber mosaic virus in chickweed (Stellaria media) in relation to the ecology of the virus

Cucumber mosaic virus (CMV) was transmitted in the seed of infected Stellaria media plants. The rate of seed transmission varied both in manually infected plants (3–21%) and in plants grown from infected seed (21–40%). In naturally infected plants the rates of transmission found were 4–29%. Seeds recovered from field soil carried 4–5% infection and in infected seed placed in the soil the virus persisted for at least 5 months. Seed transmission of CMV also occurred in infected Lamium purpureum (4%), Cerastium holosteoides (2%) and Spergula arvensis (2%) but it could not be demonstrated in six other more common weed species in five botanical families. Seed transmission in Stellaria media occurred with a British (W) and an American (Y) strain of CMV. The virus was shown to occur in S. media pollen. The importance of CMV-infected S. media seed in the soil in relation to the epidemiology of the virus is discussed.     

Further studies on cucumber mosaic virus infection of narrow-leafed lupin (Lupinus angustifolius): seed-borne infection, aphid transmission, spread and effects on grain yield

Four field trials were done with narrow-leafed lupins (Lupinus angustifolius) in 1988 - 1989, to examine the effect of sowing seed with 5% and 0.5% cucumber mosaic virus (CMV) infection on subsequent virus spread, grain yield and percentage of infection in harvested seed. A proportion of the CM V-infected seed failed to produce established plants and thus, plots sown with 5% and 0.5% infected seed contained 1.5-2.9% and 0.2-0.3% of seed-infected plants respectively. The rate of virus spread by aphids was faster and resulted in more extensive infection at maturity in plots sown with 5% infected seed than with 0.5% infected seed. In three trials, sowing 5% infected seed resulted in yield losses of 34 - 53% and CMV infection in the seed harvested of 6 - 13%. The spread of CMV infection resulting from sowing 0.5% infected seed did not significantly decrease yield. However, late CMV spread in these plots caused > 1% seed infection. In the fourth trial, which was badly affected by drought, CMV spread only slowly, there was no significant effect of CMV on grain yield and the percentage of infected seed harvested was 3–5 times less than that in the seed sown. When CMV-infected seed was sown at different depths, target depths of 8 and 11 cm decreased the incidence of seed-infected plants by c. 15% and c. 50% respectively compared with sowing at 5 cm. However, in glasshouse tests, treatment with the pre-emergence herbicide simazine failed to selectively cull out seed-infected plants. The field trials were colonised by green peach (Myzus persicae), blue-green (Acyrthosiphon kondoi) and cowpea (Aphis craccivora) aphids. When the abilities of these aphid species and of the turnip aphid (Lipaphis erysimi) in transmitting CMV from lupins to lupins were examined in glasshouse tests, short acquisition access times favoured transmission. With 5–10 min acquisition access times, overall transmission efficiencies were 10.8%, 9.4%, 6.1% and 3.9% for the green peach, cowpea, blue-green and turnip aphids respectively.     

Alfalfa mosaic and cucumber mosaic virus infection in chickpea and lentil: incidence and seed transmission

Samples collected in 1994 and 1995 from commercial crops of chickpeas and lentils growing in the agricultural region of south-west Western Australia were tested for infection with alfalfa mosaic (AMV) and cucumber mosaic (CMV) viruses, and for members of the family Potyviridae using enzyme-linked immunosorbent assay (ELISA). In 1994 no virus was detected in the 21 chickpea crops tested but in 1995, out of 42 crops, AMV was found in two and CMV in seven. With lentils, AMV and/or CMV was found in three out of 14 crops in 1994 and 4 out of 13 in 1995, both viruses being detected in two crops in each year. Similar tests on samples from chickpea and lentil crops and plots growing at experimental sites, revealed more frequent infection with both viruses. No potyvirus infection was found in chickpeas or lentils in agricultural areas either in commercial crops or at experimental sites. However, bean yellow mosaic virus (BYMV) was detected along with AMV and CMV in irrigated plots of chickpeas and lentils at a site in Perth. When samples of seed from infected crops or plots of chickpeas and lentils were germinated and leaves or roots of seedlings tested for virus infection by ELISA, AMV and CMV were found to be seed-borne in both while BYMV was seed-borne in lentils. The rates of transmission found through seed of chickpea to seedlings were 0.1–1% with AMV and 0.1–2% with CMV. Seed transmission rates with lentil were 0.1–5% for AMV, 0.1–1% for CMV and 0.8% for BYMV. Individual seed samples of lentil and chickpea sometimes contained both AMV and CMV. With both species, infection with AMV and CMV was sometimes found in commercial seed stocks or seed stocks from multiplication crops of advanced selections nearing release as new cultivars. Seed-borne virus infection has important practical implications, as virus sources can be re-introduced every year to chickpea and lentil crops or plots through sowing infected seed stocks leading to spread of infection by aphid vectors, losses in grain yield and further contamination of seed stocks.     

Losses in productivity of subterranean clover swards caused by sowing cucumber mosaic virus-infected seed

Field trials were done in 1988 - 89 at two sites to examine the effects of sowing seed stocks in which a low proportion (1.6–7.0%) of the seed was carrying cucumber mosaic virus (CMV) infection (= infected seed) and the subsequent CM V spread that results, on the productivity of swards of subterranean clover cvs Esperance, Green Range and Karridale. Except in irrigated plots of cv. Green Range, a variable proportion of the CMV-infected seedlings always failed to establish, so sowing infected seed normally resulted in plots containing fewer or far fewer seed-infected plants than expected. The rate of virus spread by aphids was faster and resulted in more extensive infection at maturity when the plots contained more seed-infected source plants. In two irrigated trials at South Perth, in which healthy and infected seed of cvs Esperance and Green Range was sown, CMV spread was extensive. When the plots were left undefoliated, herbage dry wt yields were decreased by 12 – 30% and seed yields by 53 – 64% due to infection. When they were mown, the herbage dry wt losses recorded were 17 – 24%. In three trials at Mt Barker sown with healthy and infected seed, extensive spread of CMV occurred with cv. Green Range but not with cvs Esperance and Karridale. With cv. Green Range, losses of 25 – 28% in herbage dry wt were recorded inside CMV-affected patches in mown or grazed plots, while losses were up to 13% when herbage was sampled at random. Seed yield losses were 40–42% and 53% in infected mown and undefoliated cv. Green Range plots, respectively. In the mown or grazed plots of cvs Esperance and Karridale, herbage dry wt losses recorded were up to 7% while seed yield losses were 9 – 16% in mown and 9% in undefoliated plots. The mean wt/seed of seed harvested from mown plots of cvs Green Range and Karridale sown with infected seed was 8–12% less than that of seed from mown control plots. CMV was detected in seed harvested from undefoliated cv. Green Range plots and mown plots of cvs Green Range and Karridale sown with infected seed but levels of seed infection with the mown plots were 3–5 times less than in the seed sown. Field trials were done at two sites in 1987 – 90 to examine the persistence of CMV in subterranean clover swards. CMV infection was established in 1987 and the plots were grazed in subsequent years. At Badgingarra, infection gradually decreased with little CMV being recovered by 1990. At Mt Barker, recovery of CMV was relatively poor in 1988 and even poorer in 1989, but there was some resurgence of CMV infection in 1990.     

Interactions between a seed-borne strain of cucumber mosaic cucumovirus and its lupin host

The relationship between time of inoculation with cucumber mosaic cucumovirus (CMV) and the growth, seed production and rate of seed transmission of virus in lupin (Lupinus angustifolius cv. Illyarrie) was studied in field-grown plants. Plants inoculated at the seedling stage (2 days post-emergence) showed 45% mortality. Plants infected through the seed were more stunted than plants inoculated at the seedling stage. Plants inoculated up to the mid-vegetative growth stage (58 days post-emergence) yielded ≤ 27% of the dry matter and ≤ 9% of the seed of healthy plants. Late inoculation (114 days post-emergence) did not affect dry matter yield, but reduced seed yield to 75% of that of healthy plants. Rate of seed transmission depended on the time of inoculation of plants. The maximum rate was 24.5% for plants that were inoculated at the mid-vegetative growth stage (58 days post-emergence). However, early inoculation caused a large reduction in seed yield, and it was shown that plants inoculated at the beginning of flowering (94 days post-emergence) produced greater numbers of infected progeny than plants inoculated at earlier or later times. No relationship was observed between seed weight and transmission of CMV. Infectious CMV was recovered from the embryo, but not from the testa. A simple seed transmission model was used to evaluate several hypothetical epidemics and to determine the time of inoculation which results in greatest rates of seed transmission of CMV. For example, when fewer than 73% of plants in a crop become infected with CMV, then the rate of transmission of virus in crop seeds will be greatest when inoculations are at the beginning of flowering.     

Seed-borne cucumber mosaic virus infection of subterranean clover in Western Australia

In Western Australia, infection with cucumber mosaic virus (CMV) was widespread in all three subspecies of subterranean clover (Trifolium subterraneum) growing in plots belonging to the Australian National Subterranean Clover Improvement Programme. Seed-borne CMV was detected in seed harvested in 1984–1986 of 18/25 cultivars from two collections of registered cultivars; seed transmission rates ranged up to 8.8%. Seed samples from CMV-inoculated plants of 11 cultivars transmitted the virus to 0.5–8.7% of seedlings. Seed transmission rates greater than 5% were obtained only with cvs Enfield, Green Range and Nangeela. CMV was not detected in seed harvested in 1975–1981 from one of the registered cultivar collections, in 17 commercial seed stocks from 1986 or in a survey of subterranean clover pastures.
Symptoms in subterranean clover naturally infected with CMV included mottle, leaflet downcurling and dwarfing but severity varied with cultivar and selection. CMV isolates from different sources varied in virulence when inoculated to subterranean clover; two (both from subterranean clover) were severe, two moderate and three (including one from subterranean clover) mild. In pot tests, CMV decreased herbage production and root growth (dry wts) of cv. Green Range by 49% and 59% respectively. In spaced-plants growing in plots, CMV decreased herbage production and root growth of cvs Green Range and Northam by 59–630 and seed production of cv. Green Range by 45%. In rows sown with infected seed, aphid spread increased infection levels to 75% in cv. Green Range and 44% in cv. Esperance and losses in herbage production of 42% and 29% respectively were recorded.
CMV isolated from subterranean clover included isolates from both serogroups.     

Seed-borne cucumber mosaic virus infection of narrow-leafed lupin (Lupinus angustifolius) in Western Australia

In 1986 in Western Australia, cucumber mosaic virus (CMV) infection was widespread in breeders' selections of narrow-leafed lupin (Lupinus angustifolius), and in collections of lupin cvs and wild L. angustifolius lines. When seed of some of these selections and cvs was sown, seed-borne CMV was detected in seedlings. Infection of F₁ progenies was traced to use of infected parent plants. CMV was also widespread in 25 seed crops of the new lupin cv. Wandoo but not in 42 seed crops of the new cv. Danja. When samples of the seed sown in 1986 were tested, CMV was detected in 3 - 34% of seedlings of cv. Wandoo but in none of cv. Danja. Following intensive roguing of symptom-bearing plants in the 1986 seed crop of new lupin cv. Gungurru, the level of seedling infection with CMV in seed samples after harvest was 0·1-0·2%. CMV was detected in 6 - 8%, 0·6-5% and 0 - 18% of seedlings from seed samples of established lupin cvs Chittick, Yandee and Illyarrie respectively. Highest levels of seed transmission were in seed from crops grown in high rainfall areas. When a sample of cv. Wandoo seed was graded for size by sieving, CMV was detected in seedlings grown from seed in all grades, but the smallest grade contained the highest level of infection. When seed was collected from pods at different positions on plants in a CMV-infected crop of cv. Illyarrie, seed from primary pods transmitted the virus to seedlings at a 3% rate, seed from first order lateral pods at 8% while seed from second and third order lateral pods transmitted at 13%. Examination of CMV-infected lupin crops indicated that seed-infected plants competed poorly and tended to be shaded out in dense crops but to survive in sparse crops. In 1987 during drought conditions after seeding, plant mortality was greater with seed-infected seedlings than with healthy seedlings despite wide plant spacing. An isolate of CMV from subterranean clover (Trifolium subterraneum) induced severer symptoms in lupins than four isolates from lupin; only the subterranean clover isolate prevented seed production. In tests at one lupin breeding site, CMV was found in 15 species of weeds and volunteer legumes. Fumaria officinalis, Stachys arvensis and volunteer lupins were most frequently infected.     

Seed-transmission in the ecology of nematode-borne viruses

Virus-free populations of vector nematodes can acquire tomato black ring (TBRV), raspberry ringspot (RRV) and arabis mosaic (AMV) viruses from weed seedlings grown from virus-carrying seed. When soils from fields where nematode-borne viruses occurred naturally were air-dried to kill vector nematodes and then moistened, TBRV and RRV occurred commonly in the weed seedlings that grew, but AMV occurred only rarely. Similar tests did not detect tobacco ringspot, grapevine fanleaf or tobacco rattle viruses in weed seeds in the single soil studied in each instance, although these three viruses are also seed-borne in some of their hosts. Many weed species, when infected experimentally, readily transmit TBRV and RRV to their seed, but the viruses were much commoner in naturally occurring seed of some of these species than of others. These discrepancies between the frequency of seed-transmission of viruses from experimentally infected plants and the extent of natural occurrence of infected seed seem largely to reflect the host preferences of the vectors. Infective Longidorus elongatus kept in fallow soil retained TBRV and RRV only up to 9 weeks. When weed seeds in the soil were then allowed to germinate, the nematodes reacquired virus from the infected seedlings. Some weed species were better than others as sources of virus. Persistence of these viruses in fields through periods of fallow or fasting of the vector therefore depends on a continuing supply of infected seedlings produced by virus-containing weed seeds. This is probably less true of viruses like AMV and grapevine fanleaf, which persist for 8 months or more in their vectors (Xiphinema spp.). A few seeds containing TBRV and RRV were found in soils free of vector nematodes, suggesting that the viruses are disseminated in weed seed. This probably explains how TBRV and RRV have reached a large proportion of L. elongatus populations in eastern Scotland.     

Responses of potato cultivars (Solanum tuberosum) to infection with Cucumber mosaic virus isolated from different host species

Eight isolates of Cucumber mosaic virus (CMV) isolated from seven different host species were tested for their virulence on potato cv. Desirée. Three isolates caused a systemic infection, of which one isolate from Asiatic lily (CMV-P26) and one from cucumber (CMV-J) appeared to be highly virulent, in contrast to the third isolate (CMV-M) that originated from cucumber and caused mild symptoms only. These three isolates were transmitted to 26 additional potato cultivars by mechanical inoculation in a greenhouse. All cultivars were infected with at least one CMV isolate and developed local chlorotic symptoms, but only 17 cultivars (including Desiree) developed primary systemic symptoms including necrosis, mosaic and/or malformation of leaves. Furthermore, in only five cultivars (including Desiree) CMV was transmitted to tubers and was subsequently detected in plants of the first and second vegetative progeny, the secondary symptoms of these plants being severe. The observed phenotypic responses of potatoes to CMV were not associated with the maturity type (early or late) or resistance to other viruses. Results of this study indicate a high level of biological variability among CMV isolates and that infection in potato depends on CMV isolate and potato cultivar.