Nanosheet-Facilitated Spray Delivery of dsRNAs Represents a Potential Tool to Control Rhizoctonia solani Infection

Abstract

Rhizoctonia solani is one of the important pathogenic fungi causing several serious crop diseases, such as maize and rice sheath blight. Current methods used to control the disease mainly depend on spraying fungicides because there is no immunity or high resistance available in crops. Spraying double-strand RNA (dsRNA) for induced-gene silencing (SIGS) is a new potentially sustainable and environmentally friendly tool to control plant diseases. Here, we found that fluorescein-labelled EGFP-dsRNA could be absorbed by R. solani in co-incubation. Furthermore, three dsRNAs, each targeting one of pathogenicity-related genes, RsPG1, RsCATA, and RsCRZ1, significantly downregulated the transcript levels of the target genes after co-incubation, leading to a significant reduction in the pathogenicity of the fungus. Only the spray of RsCRZ1 dsRNA, but not RsPG1 or RsCATA dsRNA, affected fungal sclerotium formation. dsRNA stability on leaf surfaces and its efficiency in entering leaf cells were significantly improved when dsRNAs were loaded on layered double hydroxide (LDH) nanosheets. Notably, the RsCRZ1-dsRNA-LDH approach showed stronger and more lasting effects than using RsCRZ1-dsRNA alone in controlling pathogen development. Together, this study provides a new potential method to control crop diseases caused by R. solani.

Double-stranded RNA targeting white mold Sclerotinia sclerotiorum argonaute 2 for disease control via spray-induced gene silencing

“…According to Mitter et al (Mitter et al, 2017), spray-delivered CMV2b-dsRNA-Cy3 was washed off by irrigation and sudden rain, but CMV2b-dsRNA-Cys3-LDH with NPs was still adhered to the leaves and offered better crop protection against the pathogen. Similar observation were reported where the dsRNA-LDH complex showed stronger and more lasting effects in controlling Rhizoctonia solani infection by targeting pathogenicity-related genes by SIGS than using dsRNA alone (Chen et al, 2022). Overall, the NPs loaded dsRNA have been found effective against numerous phytopathogenic fungi e.g., Rhizoctonia solani, Fusarium oxysporum, Sclerotinia sclerotiorum, Sclerotium rolfsii, Colletotrichum spp., etc.…”

“BioClay™”: One Step toward the Sustainable and Novel Plant Protection Method

“…These fungi cause a fusarium crown and root rot disease in tomatoes. Researchers from China found that RsCRZ1-dsRNA-LDH induced stronger RNAi than RsCRZ1-dsRNA to control the growth of Rhizoctonia solani (Chen et al, 2022).…”

A Combinatorial Nanobased Spray-Induced Gene Silencing Technique for Crop Protection and Improvement

“…Talking about nanomaterial-based delivery of dsRNA, the LDH nanosheet is one of the most powerful and efficient processes to spray RNAi on A. thaliana leaves. CMV2b-dsRNA-Cy3 got erased by sudden rain and irrigation, whereas CMV2b-dsRNA-Cys3-LDH was still attached to its leaves, providing better crop protection against the pathogens …”

“…CMV2b-dsRNA-Cy3 got erased by sudden rain and irrigation, whereas CMV2b-dsRNA-Cys3-LDH was still attached to its leaves, providing better crop protection against the pathogens. 62 Sclerotinia sclerotiorum is another pathogen that can be reduced by SIGS application infecting thale cress and oil rape seed plants.…”