Farzadfar Shirin, Pourrahim Reza
Department of Plant Virus Research, Iranian Research Institute of Plant Protection, P.O. Box 19395-1454, Tehran, Iran,
Virus Genes. 2013 Oct;47(2):347-56. doi: 10.1007/s11262-013-0948-5. Epub 2013 Jul 5.
Seventeen provinces of Iran were surveyed during 2003-2012 to find Brassicaceae hosts of Cauliflower mosaic virus (CaMV). A total 397 samples were collected from plants with virus-like symptoms. Among those tested by ELISA, 255 samples (67.2 %) were found to be infected with CaMV. Mechanical transmission tests showed that the Iranian isolates have similar biological properties on a number of Brassica and Raphanus plant species and cultivars tested. However, the isolates varied in the severity of symptoms they induced and in the capacity to infect B. oleracea var. capitata, on the basis of which they were grouped into two distinct biotypes L/MMo (latent/mild mottle) and severe (S) infection. The molecular diversity of natural population of CaMV were investigated based on the complete sequences of OFR 6 of 36 Iranian isolates collected from different geographically distant regions in Iran alongside the sequences of 14 previously reported isolates. Phylogenetic analyses indicated that the Iranian CaMV isolates belong to two groups (GI and GII). Most of the Iranian isolates fell into GI with other exotic isolates; however, the isolates from North-East Iran with Xinjiang from China fell into GII. The phylogenetic group GII (the North-East Iranian isolates) closely corresponded to the S biological group however other Iranian isolates corresponded to the L/MMo biological group. The within-population diversity was lower than the between population diversity suggesting the contribution of a founder effect on diversification of CaMV isolates. The Iranian isolates were differentiated from other exotic CaMV isolates and clustered into two RFLP groups using Hpy99I which closely corresponded to the biological and phylogenetic groups. This study showed the evolutionary process in CaMV isolates is shaped by a combination of host range differentiation and nucleotide substitution using the approach of population genetics.
2003年至2012年期间，对伊朗的17个省份进行了调查，以寻找花椰菜花叶病毒（CaMV）的十字花科寄主。共从有病毒样症状的植物上采集了397个样本。在通过酶联免疫吸附测定（ELISA）检测的样本中，发现255个样本（67.2%）感染了CaMV。机械传播试验表明，伊朗分离株在一些测试的芸苔属和萝卜属植物物种及品种上具有相似的生物学特性。然而，这些分离株在诱导症状的严重程度以及感染甘蓝变种（B. oleracea var. capitata）的能力方面存在差异，据此将它们分为两种不同的生物型L/MMo（潜伏/轻度斑驳）和严重（S）感染。基于从伊朗不同地理区域收集的36个伊朗分离株的OFR 6完整序列以及14个先前报道的分离株序列，研究了CaMV自然种群的分子多样性。系统发育分析表明，伊朗CaMV分离株属于两个组（GI和GII）。大多数伊朗分离株与其他外来分离株归入GI组；然而，来自伊朗东北部与中国新疆的分离株归入GII组。系统发育组GII（伊朗东北部分离株）与S生物组密切对应，而其他伊朗分离株与L/MMo生物组对应。种群内多样性低于种群间多样性，这表明奠基者效应在CaMV分离株多样化中起作用。伊朗分离株与其他外来CaMV分离株不同，使用Hpy99I可将其聚类为两个限制性片段长度多态性（RFLP）组，这与生物组和系统发育组密切对应。本研究表明，利用群体遗传学方法，CaMV分离株的进化过程是由寄主范围分化和核苷酸取代共同塑造的。
