Mohammadi M R, Koohi-Habibi M, Mosahebi Gh, Hajieghrari B
Department of Plant Protection, Faculty of Agriculture Islamic Azad University of Varamin, Varamin, Iran.
Commun Agric Appl Biol Sci. 2006;71(3 Pt B):1311-9.
During a growing season in 2004, 231 leaf samples of virus infected and mosaic and dwarf mosaic symptoms showing maize (Zea mays L.) plants and 258 leaf samples of mosaic showing johnsongrass (Sorghum halepens L.) plants from various corn fields in Tehran province were collected. Serological tests of DAS-ELISA and DIBA were performed on samples using antisera of sugarcane mosaic virus (SCMV), maize dwarf mosaic virus (MDMV), sorghum mosaic virus (SrMV) and johnsongrasss mosaic virus (JGMV). In both tests performed on leaf samples extractions, all samples reacted strongly with SCMV antiserum and no reaction was seen with other 3 potyviruses antisera. 0.1 M potassium phosphate buffer (pH = 7) containing 2% polyvinyl pyrrolidon (PVP) was used for mechanical inoculation and all isolates were inoculated and propagated on sweet corn cv. Pars 403 and grain sorghum cv. Kimia. In serological tests on the inoculated plants samples also only SCMV was detected. Purification of virus was done using a modified "minipurification" method and the concentration of purified virus was 11.45 mg/ml and ratio of A260/280 = 1.2 was calculated for it. Electron microscopic study using ISEM and decoration method with SCMV antiserum revealed filamentous flexuous particles of SCMV. In SDS-polyachrylamide gel electrophoresis and Western blot test using SCMV antiserum that were performed on infected samples and purified viruses, the molecular weight of the virus coat protein was approximately 37-38 KDa and a difference among the CP weights of various SCMV isolates was not found. Reverse transcription-polymerase chain reaction (RT-PCR) was done using SCMV F3 and SCMV R3 primers and amplified fragments of approximately 900 bp in size were as in expected. The host range study with selected isolates of SCMV showed that the virus isolates were not transmitted by mechanical inoculation on Avena sativa, Panicum miliaceum, Setaria italica, Pennisetum americanum, Hordeum vulgare and Triticum aestivum. The isolates produced red-brown necrotic streaks on sudangrass (Sorghum sudanense) that lately changed in systemic necrosis. In host reaction studies on sorghum (Sorghum bicolor) cultivars, the virus isolates caused severe necrotic and killer reaction on sorghum cultivars Payam, Sepideh and Speed feed, but caused systemic mosaic and non-killer reaction on sorghum cultivars Kimia, KFS2, KFS3 and Jumbo. The present study showed that SCMV is the prevalent potyvirus and the main causal agent of mosaic and dwarf mosaic on maize plants in province. Since the virus is prevalent on johnsongrass plants in marginal areas of corn fields too, it seems that the origin of the virus on corn is from johnsongrass and the virus is a special strain of sugarcane mosaic virus that infects johnsongrass too.
2004年生长季期间，从德黑兰省不同玉米田采集了231份表现出病毒感染、花叶和矮花叶症状的玉米（Zea mays L.）植株叶片样本，以及258份表现出花叶症状的约翰逊草（Sorghum halepens L.）植株叶片样本。使用甘蔗花叶病毒（SCMV）、玉米矮花叶病毒（MDMV）、高粱花叶病毒（SrMV）和约翰逊草花叶病毒（JGMV）抗血清，对样本进行了双抗体夹心酶联免疫吸附测定（DAS - ELISA）和双抗体免疫吸附测定（DIBA）血清学检测。在对叶片样本提取物进行的两项检测中，所有样本与SCMV抗血清反应强烈，而与其他3种马铃薯Y病毒抗血清均无反应。使用含有2%聚乙烯吡咯烷酮（PVP）的0.1 M磷酸钾缓冲液（pH = 7）进行机械接种，并将所有分离物接种到甜玉米品种Pars 403和粒用高粱品种Kimia上进行繁殖。对接种植株样本的血清学检测也仅检测到SCMV。采用改良的“微纯化”方法进行病毒纯化，纯化病毒浓度为11.45 mg/ml，计算其A260/280比值为1.2。使用免疫扫描电子显微镜（ISEM）和用SCMV抗血清进行的标记法进行电子显微镜研究，揭示了SCMV的丝状弯曲颗粒。在对感染样本和纯化病毒进行的十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）和蛋白质免疫印迹试验（Western blot）中，病毒外壳蛋白的分子量约为37 - 38 kDa，未发现不同SCMV分离物的外壳蛋白重量存在差异。使用SCMV F3和SCMV R3引物进行逆转录 - 聚合酶链反应（RT - PCR），扩增出大小约为900 bp的片段，与预期相符。对选定的SCMV分离物进行的寄主范围研究表明，这些病毒分离物不能通过机械接种传播到燕麦（Avena sativa）、黍（Panicum miliaceum）、狗尾草（Setaria italica）、珍珠粟（Pennisetum americanum）、大麦（Hordeum vulgare）和普通小麦（Triticum aestivum）上。这些分离物在苏丹草（Sorghum sudanense）上产生红棕色坏死条纹，随后转变为系统坏死。在对高粱（Sorghum bicolor）品种的寄主反应研究中，病毒分离物在高粱品种Payam、Sepideh和Speed feed上引起严重的坏死和致死反应，但在高粱品种Kimia、KFS2、KFS3和Jumbo上引起系统花叶和非致死反应。本研究表明，SCMV是该省玉米植株上普遍存在的马铃薯Y病毒，也是花叶和矮花叶的主要致病因子。由于该病毒在玉米田边缘地区的约翰逊草植株上也普遍存在，因此玉米上的病毒似乎起源于约翰逊草，并且该病毒是一种也能感染约翰逊草的甘蔗花叶病毒的特殊菌株。
