我国一些地区发生的小麦土传病毒病的病原研究

我国浙江、江苏、四川等省发生的小麦土传病毒病,由禾谷多粘菌(Polymyxa graminis)传播,只感染小麦,感病植株幼叶表现为退绿到黄化的条斑,老叶表现为花叶和坏死。我们提纯各地分离物研究表明,病毒粒子呈线状,直径13～14nm,长度为200～1800nm,其中350～850nm的比例较高。病毒外壳由二种分子量分别约为30kd和27kd的结构蛋白组成。病毒粒子周围能均匀地“修饰”小麦梭条斑花叶病毒(WSSMV)抗血清和小麦黄花叶病毒(WYMV)抗血清,反应均很强烈。鉴于上述特性,认为本病害是由小麦棱条斑花叶病毒(WSSMV)引起的。     

小麦土传病毒在感病小麦细胞中的分布及小麦梭条斑花叶病毒RNA组分

四川雅安、陕西长安的土传小麦病毒病由小麦梭条斑花叶病毒(WSSMV)引起,而浙江安吉、新昌、江苏宜兴的病害则由WSSMV和土传小麦花叶病毒(SBWMV)所致。WSSMV和SBWMV可以同时复合侵染同一株小麦,但在病细胞中二者彼此独立分布。我国WSSMV RNA有2个基因组,分子量分别为2.6×10~6和1.5×10~6,与日本小麦黄花叶病毒(WYMV)一致。     

利用异种动物抗血清双抗夹心法检测小麦黄花叶病毒

小麦黄花叶病毒(Wheat yellow mosaic virus,WYMV),属于马铃薯Y病毒科(Potyviridae),大麦黄花叶病毒属(Bymovirus),传播介体为禾谷多粘菌(Polymyxa graminis),与发生在欧美的小麦梭条花叶病毒(WSSMV)为同一属内的两种病毒[1].     

利用异种动物抗血清双抗夹心法检测小麦黄花叶病毒

小麦黄花叶病毒(Wheat yellow mosaic virus,WYMV),属于马铃薯Y病毒科(Potyviridae),大麦黄花叶病毒属(Bymovirus),传播介体为禾谷多粘菌(Polymyxa graminis),与发生在欧美的小麦梭条花叶病毒(WSSMV)为同一属内的两种病毒。该病毒在我国分布广泛,在长江流域各省份以及济南、陕西等都有分布,对小麦生长.发育构成严重危害。一般可引起小麦减产10％～30％,严重时达70％,甚至绝产。以往对该病害的诊断主要是根据田间的症状表现,有时很难与由其他病原或环境因子引致症状相区分,目前,关于WYMV的问接酶     

小麦黄花叶病毒的分离提纯及其血清学等特性

应用梯度离心和超速离心浓缩获得部分提纯的病毒制剂,产量约为7.45g/kg病叶提纯的病毒制剂的紫外吸收曲线呈典型的核蛋白吸收曲线,OD260/OD242和OD260/OD280的比值分别为1.24和1.38。病毒粒子呈线状,宽13—14nm,长度主要分布于250—300nm和550—700nm之间,1000nm以上的粒子也有检到。病毒外壳蛋白仅由一个分子量约为30Kd的亚基组成。在免疫电镜试验中、病毒粒子与日本WYMV抗血清发生强烈的血清学反应。新鲜病叶的超薄切片中可看到大量风轮体和膜状体。     

小麦黄花叶病毒基因组核苷酸序列分析

以小麦黄花叶病毒 (WYMV)HC分离物为材料 ,合成病毒基因组cDNA并进行序列分析 .结果表明 ,病毒RNA1共有 76 2 9个核苷酸 ,编码 1种由 2 40 7个氨基酸组成的多聚蛋白 ,切割产生病毒外壳和其他 7种可能的蛋白质 .该病毒的RNA2共有 36 39个核苷酸 ,编码 1种由 90 3个氨基酸组成的蛋白 ,可能切割产生 2种非结构蛋白 .WYMV虽然与小麦梭条花叶病毒 (WSSMV)在基因组结构上具有相似性 ,但是两者间在核苷酸及氨基酸水平上的同源性却分别低于 70 %和 75 % .由此结果可以确认 ,WYMV与WSSMV是大麦黄花叶病毒属 (Bymovirus)的 2种不同病毒 .     

小麦黄花叶病毒基因组核苷酸序列分析*1)

以小麦黄花叶病毒(WYMV)HC分离物为材料,合成病毒基因组cDNA并进行序列分析.结果表明,病毒RNA1共有7 629个核苷酸,编码1种由2 407个氨基酸组成的多聚蛋白,切割产生病毒外壳和其他7种可能的蛋白质.该病毒的RNA2共有3 639个核苷酸,编码1种由903个氨基酸组成的蛋白,可能切割产生2种非结构蛋白.WYMV虽然与小麦梭条花叶病毒(WSSMV)在基因组结构上具有相似性,但是两者间在核苷酸及氨基酸水平上的同源性却分别低于70%和75%.由此结果可以确认,WYMV与WSSMV是大麦黄花叶病毒属(Bymovirus)的2种不同病毒.     

小麦黄花叶病毒低分子量RNA1的鉴定

利用小麦黄花叶病毒(Wheat yellow mosaic virus, WYMV)潢川分离物连续继代机械接种感病小麦品种鄂恩1号,经继代接种12代以上的小麦症状明显加重,Northern blot检测发现一条明显的低分子量病毒RNA1(LMW RNA1),并在随后至26代的继代接种发病材料中稳定存在,但在利用同样病叶提纯的病毒粒子内检测不到LMW RNA1,表明其不能被包装到病毒粒子内.序列分析结果表明,低分子量RNA1由病毒RNA1发生内部缺失而产生,从RNA1 5'端非编码区(第68nt)到CI基因编码区的3'端(第2448nt)共缺失2380个核苷酸,在缺失区域两端的结合位点存在六个碱基的正向重复序列CGTCTC.据此对此低分子量RNA1的缺失机制进行了讨论,认为由一种模板转换机制导致了缺失的发生.     

意大利小麦真菌传棒状病毒与欧洲小麦花叶病毒和土传黑麦花叶病毒属同一种病毒

测定了从意大利硬红小麦上分离的一个真菌传棒状病毒分离物两个RNA的核苷酸全序列, 并与美国的土传小麦花叶病毒(SBWMV)、最近发表的从法国小麦上分离的欧洲小麦花叶病毒(EWMV)和从德国黑麦和小麦上分离的3个土传黑麦花叶病毒(SBRMV-C,-G, -O)进行了序列比较和系统树分析. 结果表明, 意大利分离物的RNA1和RNA2分别由7 025和3 688个碱基组成, 与EWMV的同源性分别为97.5%和98.6%, 与SBRMV-G 为95.5%和85.8%, 而与SBWMV 仅为70.6%和64.5%. 因此, 意大利分离物与SBWMV不同, 但与EWMV和SBRMV同属一种病毒, 建议将这些欧洲病毒命名为土传禾谷类花叶病毒(SBCMV), 以避免与以前的名字混淆.     

小麦黄花叶病毒低分子量RNA1的鉴定

利用小麦黄花叶病毒(Wheat yellow mosaic virus, WYMV)潢川分离物连续继代机械接种感病小麦品种鄂恩1号,经继代接种12 代以上的小麦症状明显加重, Northern blot 检测发现一条明显的低分子量病毒RNA1(LMW RNA1),并在随后至26代的继代接种发病材料中稳定存在,但在利用同样病叶提纯的病毒粒子内检测不到LMW RNA1,表明其不能被包装到病毒粒子内。序列分析结果表明,低分子量RNA1 由病毒RNA1 发生内部缺失而产生,从RNA1 5′端非编码区(第68nt)到CI基因编码区的3′端(第2448nt)共缺失2380 个核苷酸,在缺失区域两端的结合位点存在六个碱基的正向重复序列CGTCTC。据此对此低分子量RNA1 的缺失机制进行了讨论,认为由一种模板转换机制导致了缺失的发生。     

我国真菌传线状小麦花叶病毒病病原初步鉴定为小麦黄花叶病毒(WYMV)

由禾谷多粘菌（Ｐｏｌｙｍｙｘａｇｒａｍｉｎｉｓ）传播的线状小麦花叶病毒有两种,一种是加拿大首先报道的小麦梭条斑花叶病毒（ＷＳＳＭＶ）,另一种是日本报道的小麦黄花叶病毒（ＷＹＭＶ）。这两种病毒粒子形态以及血清学性质非常相似,但核酸序列存在一定差异。经反转录聚合酶链反应（ＲＴＰＣＲ）和单链构象多态性分析（ＳＳＣＰ）,明确我国广泛发生的禾谷多粘菌传线状小麦花叶病毒都是小麦黄花叶病毒,但供试的８个分离物ＲＮＡ１和ＲＮＡ２序列存在差异,无一彼此完全相同     

Production and Characterization of Monoclonal Antibodies to Barley Yellow Mosaic Virus and Their Use in Detection of Four Bymoviruses

Six monoclonal antibodies (MAbs) against a French isolate of barley yellow mosaic virus (BaYMV) pathotype 2 were produced and their isotypes determined. These MAbs were compared in ELISA for their reactivity with different isolates of BaYMV, wheat yellow mosaic virus (WYMV), wheat spindle streak mosaic virus (WSSMV) and oat mosaic virus (OMV).The six MAbs detected BaYMV in TAS ELISA and western blot, whereas in ACP ELISA no reaction was observed with isolates of BaYMV and WYMV. These MAbs could recognize the sequential motifs situated at the surface of viral particles. The six MAbs detected all the European isolates of BaYMV pathotype 1 and 2 and the Japanese isolate of this viral pathotype 1–1. In contrast to other MAbs, MAb IV did not react with the Japanese isolate of BaYMV pathotype II-l. In TAS ELISA. MAbs I, II, III, and IV detected the Japanese isolate of WYMV and American isolates of WSSMV only when they were captured by anti-WYMV polyclonal antibodies, A French isolate of OMV was detected only by the MAbs I and II in TAS ELISA with Polyclonal anti-BaYMV.     

Analysis of nucleotide sequence of wheat yellow mosaic virus genomic RNAs

Wheat yellow mosaic virus (WYMV) isolate HC was used for viral cDNA synthesis and sequencing. The results show that the viral RNA1 is 7629 nueleotides encoding a polyprotein with 2407 amino acids, from which seven putative proteins may be produced by an autolytie cleavage processing besides the viral coat protein. The RNA2 is 3639 nueleotides and codes for a polypretein of 903 amino acids, which may contain two putative non-structural proteins. Although WYMV shares a similarity in genetic organization to wheat spindle streak mosaic virus (WSSMV), the identities in their nucleotide sequences or deduced amino acid sequences are as low as 70% and 75 % respectively. Based on this result, it is confirmed that WYMV and WSSMV are different species within Bymovirus.     

Occurrence of fungally transmitted wheat mosaic viruses in China

A soil-borne mosaic disease of winter wheat in Sichuan, Shaanxi, Hubei and Henan provinces was associated with infection by a virus with filamentous particles and that in Shandong, Anhui, Jiangsu and Zhejiang provinces by co-infection with this virus and soil-borne wheat mosaic virus. The virus with filamentous particles was identified serologically, by particle sizes, cytopathology and the molecular weights of the coat protein and the two RNA species to be either wheat spindle streak mosaic virus (WSSMV) or wheat yellow mosaic virus. These viruses are probably isolates of the same virus and the name WSSMV is preferred. In baiting tests using infested soil, the dilution endpoints for detecting WSSMV were 1/625-1/15625, and for the fungus vector, Polymyxa graminis, 1/3125-1/15625.     

First Report of Soil‐Borne Wheat Mosaic Virus (SBWMV)‐Infecting Triticale in Poland

The virus in naturally infected, stunted triticale plants was identified as soil‐borne wheat mosaic virus (SBWMV). The infected plants were collected in the Southern Wielkopolska region (Western Poland). Molecular analysis including RT‐PCR, and sequencing of the complete coding sequence of coat protein gene, was performed. The sequence of the Polish isolate of SBWMV (SBWMV‐Pol1) shared 100, 99 and 98% identities with the corresponding regions of De1 (AF519799), OKL‐1 (X81639) and US‐Nebraska (L07938) isolates of SBWMV, respectively. Phylogenetic analyses showed that the Polish isolate, SBWMV‐Pol1, clustered together with other SBWMV isolates. This is the first report of the occurrence of SBWMV in Poland and the second of its presence in Europe.     

Responses of some Asian and European barley cultivars to UK and Chinese isolates of soil-borne barley mosaic viruses

In field plots at Yancheng, Jiangsu, China, a range of European and Asian barley cultivars was grown in soil from three sites in China infested with barley yellow mosaic virus (BaYMV). Most of the cultivars resistant to the common European strain of BaYMV were susceptible to the Chinese isolates but cv. Energy remained disease-free. Barley mild mosaic virus (BaMMV) was also detected in one of these soils but affected only one Chinese cultivar and not those susceptible to BaMMV in Europe. This is the first report of BaMMV in China. Inoculation experiments confirmed the different cultivar response to UK and Chinese isolates of BaYMV and showed that resistance was to the virus and not to the vector. A range of Chinese cultivars selected for resistance to BaYMV were also resistant to a UK isolate of BaMMV.     

Molecular analysis of the capsid protein gene of a german isolate of barley mild mosaic virus

Summary Barley mild mosaic virus (BaMMV) is one of the agents causing the barley yellow mosaic disease. The sequence corresponding to the 3end of the BaMMV RNA1 of a German isolate was sequenced and the coding sequence for the 251 amino acid containing capsid protein was determined. Comparison of this sequence to other potyviral sequences and to the corresponding sequence of two Japanese isolates of BaMMV was done. The three different isolates of BaMMV show a high degree of similarity.Abbrevations BaMMV barley mild mosaic virus - BaYMV barley yellow mosaic virus; bp: base pair - IPTG isopropyl -D thiogalactopyranoside - kb kilo base - NTR nontranslated region - ORF open reading frame - PVDF polyvinylidene difluoride