Silencing of the AV2 gene by antisense RNA protects transgenic plants against a bipartite begomovirus

Abstract

Whitefly-transmitted geminiviruses (genus Begomovirus) are phytopathogens that cause heavy losses to crops worldwide. Efforts to engineer resistance against these viruses are focused mainly on silencing of complementary-sense virus genes involved in virus replication. Here we have targeted a virion-sense gene (AV2) to develop resistance against Tomato leaf curl New Delhi virus, a bipartite begomovirus prevalent throughout the Indian subcontinent. We show that tobacco plants transformed with an antisense construct targeting this gene are resistant to the virus. Following challenged with the virus, transgenic plants remained symptomless, although viral DNA could be detected in some plants by PCR. This is the first report of transgenic resistance against a bipartite begomovirus obtained by targeting a virion-sense gene. The relatively conserved nature of the gene suggests that the technology may be useful to develop broad-spectrum resistance which is required because of the fact that plants are often infected with multiple begomoviruses in the field.

Resistance to Sri Lankan Cassava Mosaic Virus (SLCMV) in Genetically Engineered Cassava cv. KU50 through RNA Silencing

“…We show that resistance was acquired by RNA silencing through the production of transgene-specific siRNA. The present study and work reported elsewhere [ 40 , 41 ] suggests that AV1 / AV2 could be targeted to confer resistance to geminiviruses.…”

“…Furthermore, the AV2 protein of tomato leaf curl virus (ToLCV) and tomato yellow leaf curl virus (TYLCV) is shown to act as a potent suppressor of gene silencing activity. Silencing of AV2 gene of ToLCV by antisense RNA [ 40 ] and AV1/AV2 genes of ToLCV by artificial micro RNA [ 41 ] resulted to increased resistance to the virus in transgenic tobacco and tomato, respectively. Moreover, SLCMV DNA A has been reported to have properties of a monopartite begomovirus, which in the absence of DNA B, can induce upward leaf roll and vein swelling symptoms similar to those produced by monopatrtite begomovirus [ 10 ], indicating that the AV2 protein maybe involved in cell-to-cell movement.…”

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

“…Moreover, V2 encoded by CLCuMV is a very strong suppressor of gene silencing [10]. Tobacco plants were developed harboring an antisense construct targeting the AV2 gene of Tomato leaf curl New Delhi Virus (ToLCNDV) [47]. Upon challenging with virus-infectious clones of ToLCNDV, transgenic plants remained asymptomatic, although viral DNA could be detected by PCR.…”

Mechanically Untying a Protein Slipknot: Multiple Pathways Revealed by Force Spectroscopy and Steered Molecular Dynamics Simulations

“…Due to its structural importance and its role in the folding of knotted proteins, we combined single molecule force spectroscopy and steered molecular dynamics (SMD) simulations to investigate the unfolding mechanism of the slipknotted protein AFV3-109. AFV3-109 is a protein from Acidianus Filamentous Virus 3 with unknown biological function, although structural analysis of AFV3-109 suggests that it could interact with nucleic acids 20 . Among the known slipknotted proteins, AFV3-109 has a relatively simple structure.…”

“…As shown in Fig. 1, the core of AFV3-109 is a β-sheet with five β-strands connected by helices and loops 20 . A clear slipknot conformation is present in AFV3-109 with a knotting loop (colored in yellow, Fig.…”