Polycistronic Artificial microRNA-Mediated Resistance to Cucumber Green Mottle Mosaic Virus in Cucumber.

Barbara Baker,Chaoqiong Liang,Shuo Miao,Laixin Luo,Jianqiang Li

doi:10.3390/ijms222212237

Abstract

Cucumber green mottle mosaic virus (CGMMV), as a typical seed-borne virus, causes costly and devastating diseases in the vegetable trade worldwide. Genetic sources for resistance to CGMMV in cucurbits are limited, and environmentally safe approaches for curbing the accumulation and spread of seed-transmitted viruses and cultivating completely resistant plants are needed. Here, we describe the design and application of RNA interference-based technologies, containing artificial microRNA (amiRNA) and synthetic trans-acting small interfering RNA (syn-tasiRNA), against conserved regions of different strains of the CGMMV genome. We used a rapid transient sensor system to identify effective anti-CGMMV amiRNAs. A virus seed transmission assay was developed, showing that the externally added polycistronic amiRNA and syn-tasiRNA can successfully block the accumulation of CGMMV in cucumber, but different virulent strains exhibited distinct influences on the expression of amiRNA due to the activity of the RNA-silencing suppressor. We also established stable transgenic cucumber plants expressing polycistronic amiRNA, which conferred disease resistance against CGMMV, and no sequence mutation was observed in CGMMV. This study demonstrates that RNA interference-based technologies can effectively prevent the occurrence and accumulation of CGMMV. The results provide a basis to establish and fine-tune approaches to prevent and treat seed-based transmission viral infections.

Highlights

Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
To determine whether the polycistronic artificial microRNA (amiRNA) construct can decrease the transmission and pathogenicity of Cucumber green mottle mosaic virus (CGMMV) transmitted by seeds or whether the resistance effect of amiR246 would be affected by virus accumulation, we evaluated the effectiveness of amiR246 in protoplasts of CGMMV-infected cucumber
To determine whether the polycistronic amiRNA construct can decrease the transmission and pathogenicity of CGMMV transmitted by seeds or whether the re‐

Summary

Introduction

Seed-based transmission of viruses via contaminated seed coats or seed embryos and the infection of germinating seedlings represents a major challenge to plant breeding for many crops, including cucurbits. Due to the lack of effective chemicals for virus disease control, many researchers have focused on understanding the interaction mechanisms between viruses and hosts in order to develop potential resistant materials or breed resistant cultivars [1,2]. Cucumber plants can be protected from highly infectious strains via cross-protection, diseases can still emerge due to interactions with other viruses, mixed infections, or recombination [11], and effective biological measures are still needed for disease prevention and control

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Methods

Conclusion