Walsh HA, Vanderschuren H, Taylor S, Rey MEC. RNA silencing of
South African cassava mosaic virus in transgenic cassava expressing AC1/AC4 hp- RNA induces tolerance.
ACTA ACUST UNITED AC 2019;
24:e00383. [PMID:
31763196 PMCID:
PMC6864324 DOI:
10.1016/j.btre.2019.e00383]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/13/2019] [Accepted: 10/02/2019] [Indexed: 11/29/2022]
Abstract
A hairpin-RNA construct targeting South African cassava mosaic virus AC1/AC4 overlapping genome region confers tolerance in cassava.
Viral load and symptom severity were significantly lower in transgenic lines transformed with AC1/AC4 construct compared to wildtype cv.60444.
SACMV transgenic lines infected with SACMV displayed a recovery phenotype similar to cassava mosaic disease-tolerant cassava landrace TME3.
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.
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