Double-Stranded RNA Targeting Dicer-Like Genes Compromises the Pathogenicity of Plasmopara viticola on Grapevine

Abstract

Downy mildew caused by Plasmopara viticola is one of the most devastating diseases of grapevine, attacking all green parts of the plant. The damage is severe when the infection at flowering stage is left uncontrolled. P. viticola management consumes a significant amount of classical pesticides applied in vineyards, requiring efficient and environmentally safe disease management options. Spray-induced gene silencing (SIGS), through the application of exogenous double-stranded RNA (dsRNA), has shown promising results for the management of diseases in crops. Here, we developed and tested the potential of dsRNA targeting P. viticola Dicer-like (DCL) genes for SIGS-based crop protection strategy. The exogenous application of PvDCL1/2 dsRNA, a chimera of PvDCL1 and PvDCL2, highly affected the virulence of P. viticola. The reduced expression level of PvDCL1 and PvDCL2 transcripts in infected leaves, treated with PvDCL1/2 dsRNA, was an indication of an active RNA interference mechanism inside the pathogen to compromise its virulence. Besides the protective property, the PvDCL1/2 dsRNA also exhibited a curative role by reducing the disease progress rate of already established infection. Our data provide a promising future for PvDCL1/2 dsRNA as a new generation of RNA-based resistant plants or RNA-based agrochemical for the management of downy mildew disease in grapevine.

Small RNA-based plant protection against diseases

“…They reported that antisense sRNAs targeting the Hpa-CesA3 gene in Emoy2 and Cala2 isolates inhibited spore germination and thus infection of Arabidopsis , while sense sRNAs had no obvious effect on Hpa pathogenicity. When Haile et al (2021) used dsRNA targeting the DCL1 and DCL2 genes in grapevine downy mildew pathogen Plasmopara viticola , they observed reduction in the expression level of these genes as well as in the disease progress rate in the already established infection. Similar SIGS studies with dsRNA against the late blight pathogen P. infestans has been carried out by Kalyandurg et al (2021) .…”

Artificial nanovesicles for dsRNA delivery in spray induced gene silencing for crop protection

“…Studies in other organismal interactions have demonstrated other microbes/pathogens, including plant fungal pathogens Fusarium oxysporum 18 and Verticillium dahliae 7 , an oomycete pathogen H. arabidopsidis 16 , an animal fungal pathogen Beauveria bassiana of mosqiuito 17 , a bacterial pathogen 19 and even symbiotic microbes, such as ectomycorrhizal fungus Pisolithus microcarpus 20 and Rhizobium (Bradyrhizobium japonicum) 21 , also utilize host Argonaute proteins for crosskingdom RNAi. The biogenesis of these pathogen sRNAs involved in cross-kingdom RNAi are also largely dependent on pathogen DCL proteins [7][8]10,15,[22][23][24][25][26] . These studies demonstrate crosskingdom RNAi is a conserved mechanism across different species, including plant and animal hosts.…”

Editorial: Advances and Challenges of RNAi Based Technologies for Plants—Volume 2

“…Grape breeding programs aiming at the introgression of resistance traits from wild species to cultivated varieties have the limit to lose trait specificity of clones identified in important vine cultivars. Target sequences coding for Dicer and Dicer-like ( DCL) proteins have been identified as crucial genes for the pathogenicity of B. cinerea and P. viticola and used in SIGS approaches to control these two severe pathogens (Wang et al, 2016 ; Capriotti et al, 2020 ; Haile et al, 2021 ). A SIGS approach against the oomycete P. viticola was shown to work effectively both as preventive and therapeutic treatment (Haile et al, 2021 ).…”

“…Target sequences coding for Dicer and Dicer-like ( DCL) proteins have been identified as crucial genes for the pathogenicity of B. cinerea and P. viticola and used in SIGS approaches to control these two severe pathogens (Wang et al, 2016 ; Capriotti et al, 2020 ; Haile et al, 2021 ). A SIGS approach against the oomycete P. viticola was shown to work effectively both as preventive and therapeutic treatment (Haile et al, 2021 ). A different approach for downy mildew control is presented by Marcianò et al ( 2021 ) who silenced a grapevine susceptibility gene by exogenous dsRNA application, resulting in reduced disease severity after artificial P. viticola inoculation.…”