RNA interference-based resistance against a legume mastrevirus

Abstract

BackgroundRNA interference (RNAi) is a homology-dependant gene silencing mechanism and has been widely used to engineer resistance in plants against RNA viruses. However, its usefulness in delivering resistance against plant DNA viruses belonging to family Geminiviridae is still being debated. Although the RNAi approach has been shown, using a transient assay, to be useful in countering monocotyledonous plant-infecting geminiviruses of the genus Mastrevirus, it has yet to be investigated as a means of delivering resistance to dicot-infecting mastreviruses. Chickpea chlorotic dwarf Pakistan virus (CpCDPKV) is a legume-infecting mastrevirus that affects chickpea and other leguminous crops in Pakistan.ResultsHere a hairpin (hp)RNAi construct containing sequences encompassing part of replication-associated protein gene, intergenic region and part of the movement protein gene of CpCDPKV under the control of the Cauliflower mosaic virus 35S promoter has been produced and stably transformed into Nicotiana benthamiana. Plants harboring the hairpin construct were challenged with CpCDPKV. All non-transgenic N. benthamiana plants developed symptoms of CpCDPKV infection within two weeks post-inoculation. In contrast, none of the inoculated transgenic plants showed symptoms of infection and no viral DNA could be detected by Southern hybridization. A real-time quantitative PCR analysis identified very low-level accumulation of viral DNA in the inoculated transgenic plants.ConclusionsThe results presented show that the RNAi-based resistance strategy is useful in protecting plants from a dicot-infecting mastrevirus. The very low levels of virus detected in plant tissue of transgenic plants distal to the inoculation site suggest that virus movement and/or viral replication was impaired leading to plants that showed no discernible signs of virus infection.

Amplicon-Based RNA Interference Targeting V2 Gene of Cotton Leaf Curl Kokhran Virus-Burewala Strain Can Provide Resistance in Transgenic Cotton Plants

“…According to Ali et al [43], effective resistance in plants against monopartite begomoviruses can be obtained by applying a miRNA approach. [15, 41–44]. …”

Engineering geminivirus resistance in Jatropha curcus

“…Single target gene approaches have first been used. For example, sequences targeting the AC1 gene (which encodes the multifunctional Rep protein), the coat protein gene and AC4 gene have been shown to confer geminivirus resistance in tomato, bean and tobacco plants [ 14 - 16 , 30 - 32 ]. In the case of the Chickpea chlorotic dwarf Pakistan virus (CpCDPKV), a member of Mastrevirus (also a member of the Geminiviridae family) a multi-target approach was adopted.…”

Tropical Food Legumes

“…Of these, only genetically engineered common bean resistant to BGMV has been commercialized in Brazil (Tollefson, 2011). RNAi-based approaches are being exploited to develop virus resistance in chickpeas (Nahid, Amin, Briddon, & Mansoor, 2011). Despite the progress in genomics of legumes (Sharma, Upadhyaya, Varshney, & Gowda, 2013;Varshney, Mohan et al, 2013;Varshney, Song, et al, 2013) and availability of tools for transforming the plants, incorporation of resistance to economically important legume viruses by genetic engineering is yet to be accomplished on a commercial scale.…”