中文摘要：尽管酸橙（SO）砧木的农艺特性让人颇为满意，但柑桔衰退病毒（CTV）可在大田中引起以酸橙（SO）为砧木的柑橘衰退和死亡，这迫使在受灾国家中使用耐衰退砧木来替代酸橙砧木。衰退的柑橘植株表现出韧皮部坏死症状。相对于其他柑橘病毒来说，酸橙极易受CTV的影响。本文通过以柑橘叶斑病毒为载体使不同的柑橘基因沉默，研究了RNA沉默和水杨酸（SA）防御路径在酸橙抵抗CTV中的应用。研究发现，相对于未沉默的对照来说，与防御路径相关的RDR1、NPR1和 DCL2/DCL4基因的沉默增强了病毒在SO植株中的传播和累积；而与过敏反应有关的NPR3/NPR4基因的沉默导致了CTV的累积略有减少，并降低了以SO为砧木且感染了CTV的粗皮柠檬植株的矮缩。此外，还发现CTV RNA沉默抑制子p20和p23在大多数毒力菌株中的抑制活性较高，也会抑制SA信号防御。
外文摘要：Citrus tristeza virus (CTV) induces in the field the decline and death of citrus varieties grafted on sour orange (SO) rootstock, which has forced the use of alternative decline-tolerant rootstocks in affected countries, despite the highly desirable agronomic features of the SO rootstock. Declining citrus plants display phloem necrosis below the bud union. In addition, SO is minimally susceptible to CTV compared with other citrus varieties, suggesting partial resistance of SO to CTV. Here, by silencing different citrus genes with a Citrus leaf blotch virus-based vector, we have examined the implication of the RNA silencing and salicylic acid (SA) defence pathways in the resistance of SO to CTV. Silencing of the genes RDR1, NPR1 and DCL2/DCL4, associated with these defence pathways, enhanced virus spread and accumulation in SO plants in comparison with non-silenced controls, whereas silencing of the genes NPR3/NPR4, associated with the hypersensitive response, produced a slight decrease in CTV accumulation and reduced stunting of SO grafted on CTV-infected rough lemon plants. We also found that the CTV RNA silencing suppressors p20 and p23 also suppress the SA signalling defence, with the suppressor activity being higher in the most virulent isolates.
外文关键词：citrus decline；CLBV；reverse genetics；salicylic acid signalling defence suppressor；viral vector
作者：Gomez-Munoz, Neus; Velazquez, Karelia; Vives, Maria Carmen; 等
作者单位：西班牙IVIA
期刊名称：MOLECULAR PLANT PATHOLOGY
期刊影响因子：4.697
出版年份：2017
出版刊次：12
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