Carvajal-Yepes Monica, Olaya Cristian, Lozano Ivan, Cuervo Maritza, Castaño Mauricio, Cuellar Wilmer J
Virology Laboratory, Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), AA 6713 Cali, Colombia.
Germplasm Health Laboratory, Genetic Resources Program, International Center for Tropical Agriculture (CIAT), AA 6713 Cali, Colombia.
Virus Res. 2014 Jun 24;186:76-86. doi: 10.1016/j.virusres.2013.12.011. Epub 2013 Dec 25.
In the Americas, different disease symptoms have been reported in cassava including leaf mosaics, vein clearings, mottles, ring spots, leaf distortions and undeveloped and deformed storage roots. Some viruses have been identified and associated with these symptoms while others have been reported in symptomless plants or latent infections. We observed that reoviruses associated with severe root symptoms (RS) of Cassava Frogskin Disease (CFSD) are not associated with leaf symptoms (LS) observed in the cassava indicator plant 'Secundina'. Neither were these LS associated with the previously characterized Cassava common mosaic virus, Cassava virus X, Cassava vein mosaic virus or phytoplasma, suggesting the presence of additional pathogens. In order to explain LS observed in cassava we used a combination of biological, serological and molecular tests. Here, we report three newly described viruses belonging to the families Secoviridae, Alphaflexiviridae and Luteoviridae found in cassava plants showing severe RS associated with CFSD. All tested plants were infected by a mix of viruses that induced distinct LS in 'Secundina'. Out of the three newly described viruses, a member of family Secoviridae could experimentally induce LS in single infection. Our results confirm the common occurrence of complex viral infections in cassava field-collected since the 1980s.
在美洲，木薯出现了不同的病害症状，包括叶片花叶病、叶脉黄化、斑驳、环斑、叶片扭曲以及贮藏根发育不良和畸形。已鉴定出一些病毒与这些症状有关，而其他病毒则在无症状植物或潜伏感染中被发现。我们观察到，与木薯蛙皮病（CFSD）严重根症状（RS）相关的呼肠孤病毒与木薯指示植物“Secundina”中观察到的叶症状（LS）无关。这些叶症状也与先前鉴定的木薯普通花叶病毒、木薯病毒X、木薯叶脉花叶病毒或植原体无关，这表明存在其他病原体。为了解释木薯中观察到的叶症状，我们结合了生物学、血清学和分子检测方法。在此，我们报告了在表现出与CFSD相关的严重根症状的木薯植株中发现的三种新描述的病毒，它们分别属于双生病毒科、甲型柔性病毒科和黄症病毒科。所有测试植株都感染了多种病毒的混合体，这些病毒在“Secundina”中诱导出不同的叶症状。在这三种新描述的病毒中，双生病毒科的一个成员在单一感染时可实验性地诱导叶症状。我们的结果证实了自20世纪80年代以来在田间采集的木薯中复杂病毒感染普遍存在。
