Walsh H A, Vanderschuren H, Taylor S, Rey M E C
School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa.
Plant Genetics Laboratory, TERRA Teaching and Research Unit, University of Liège, Gembloux Agro-Bio Tech, Belgium.
Biotechnol Rep (Amst). 2019 Oct 30;24:e00383. doi: 10.1016/j.btre.2019.e00383. eCollection 2019 Dec.
Cassava mosaic disease (CMD), caused by geminiviruses, is a major hurdle to cassava production. Due to the heterozygous nature of cassava, breeding for virus resistance is difficult, but cassava has been shown to be a good candidate for genetic engineering using RNA interference (RNAi). T This study reports on the ability of a transgene-derived RNA hairpin, homologous to an overlapping region of the SACMV replication associated protein and putative virus suppressor of silencing protein (AC1/AC4), to confer tolerance in the CMD-susceptible model cassava cultivar 60444. Three of the fourteen transgenic lines expressing SACMV AC1/AC4 hairpin-derived siRNAs showed decreased symptoms and viral loads compared to untransformed control plants. Expression of SACMV AC1/AC4 homologous siRNAs showed that this tolerance is most likely associated with post-transcriptional gene silencing of the virus. This is the first report of targeting the overlapping AC1 and AC4 genes of SACMV conferring CMD tolerance in cassava.
木薯花叶病（CMD）由双生病毒引起，是木薯生产的主要障碍。由于木薯的杂合性质，培育抗病毒品种很困难，但木薯已被证明是使用RNA干扰（RNAi）进行基因工程的良好候选对象。本研究报道了一种转基因来源的RNA发夹结构，它与SACMV复制相关蛋白和假定的病毒沉默抑制蛋白（AC1/AC4）的重叠区域同源，能够使易感CMD的木薯模型品种60444产生耐受性。与未转化的对照植株相比，在表达SACMV AC1/AC4发夹结构衍生的siRNA的14个转基因株系中，有3个表现出症状减轻和病毒载量降低。SACMV AC1/AC4同源siRNA的表达表明，这种耐受性很可能与病毒的转录后基因沉默有关。这是关于靶向SACMV的重叠AC1和AC4基因赋予木薯CMD耐受性的首次报道。
