侵染红花的黄瓜花叶病毒的鉴定及株系初步研究

Identification and characterization of two cucumber mosaic virus isolatesnaturally infecting safflower (Carthamus tinctaris)

１９９５和１９９６年分别在武昌和云南红花病株上获得两个黄瓜花叶病毒（ＣＭＶ）分离物ＣＭＶ—ＣＷ和ＣＭＶ—ＣＹ。ＣＭＶ—ＣＷ引起红花黄化花叶、严重矮化，而ＣＭＶ—ＣＹ仅引起红花轻花叶。在供试２３种植物中，两个分离物侵染１６种植物。两个分离物均能被桃蚜以非持久性方式传播，不通过红花种传；体外稳定性状分别为：致死温度５５～６０℃和５０～６０℃，稀释限点１０－４～１０－５和１０－３～１０－４，体外存活期３ｄ和４ｄ；病毒颗粒球状，直径分别为２７．２ｎｍ和２８．０ｎｍ；外壳蛋白分子量分别为２７５００和２８１００Ｄ。ＣＭＶ—ＣＷ和ＣＹ血清学性质和ＣＭＶ—ＣＡ相近。通过ＲＴ—ＰＣＲ扩增，获得ＣＭＶ—ＣＷ和ＣＭＶ—ＣＹ预期的５３４ｂｐ病毒外壳蛋白基因ｃＤＮＡ片断。株系研究表明，参试的ＣＭＶ—ＣＷ、ＣＭＶ—ＣＹ和其他２个ＣＭＶ中国分离物在温度敏感实验和血清学性质上与ＣＭＶ—Ｄ株系一致或相近，属于ＣＭＶ亚组Ｉ。依据在一组寄主植物上的反应，将４个参试ＣＭＶ分离物作了初步株系划分。

Two cucumber mosaic virus (CMV) isolates, CW and CY, isolated from the diseased safflower (Carthamus tinctaris) plants in Wuchang, Hubei province and Midun county, Yunan province were identified and characterized on the basis of biological properties, serology, particle morphology, molecular weight of coat protein and RTPCR assay of the virus. Both CMVCW and CMVCY infected 19 species of plants tested in the greenhouse. Both isolates were transmitted by aphid (Myzus persicae) with nonpersistent maner, but not transmitted through safflower seeds. The viral particles were isometric with diameter in 27.2nm and 28.0nm. The safflower sap of CMVCW and CMVCY had TIP of 5560 and 5055 , DEP of 10-410-5 and 10-310-4, LIV of 3 and 4 days. Molecular weight of coat protein of the two isolates were 27 500 and 28 100 dalton, respectively. Two isolates were closely related to CMVCA serologically. A predicted 534bp length of cDNA of partial coat protein gene was amplified by RTPCR with CMVCW and CMVCY infected leave Both isolates were closely related to CMVD (type strain in CMV subgroup), distinct to CMVS (type strain in CMV subgroup ) serologically. Based on the host reactions on a group of the indicative plants the strain designation was proposed for five CMV isolates tested.