Host-induced gene silencing of PcCesA3 and PcOSBP1 confers resistance to Phytophthora capsici in Nicotiana benthamiana through NbDCL3 and NbDCL4 processed small interfering RNAs

Functionalized Carbon Dot‐Delivered RNA Nano Fungicides as Superior Tools to Control Phytophthora Pathogens through Plant RdRP1 Mediated Spray‐Induced Gene Silencing

“…We have proven that HIGS could induce efficacious gene silencing in Phytophthora through transcriptional level regulation. [17] Surprisingly, the case in SIGS was quite different. The effect of dsRNA molecules on target genes was first examined by qRT-PCR analysis.…”

“…To investigate the mechanism of SIGS and explore how to induce translation inhibition in Phytophthora, siRNAs generation in plant cells after dsRNA or dsRNA-CDs spraying were analyzed. Interestingly, unlike only 21-/24-nt siRNAs were generated in HIGS vectors-expressing plants, [17] signals corresponding to a variety of lengths (20-nt to 30-nt) of siRNAs targeting CesA3 or OSBP1 arose in dsCes3-or dsOSBP-2-sprayed plants. These signals grew stronger in plants treated with dsCes3-CDs or dsOSBP-2-CDs, whereas there was no signal in control plants (Figure 7G,H).…”

“…We further discovered that various lengths of siRNAs were generated via SIGS, which differs significantly from HIGS, where mainly 21-or 24-nt siRNAs are involved in gene silencing. [17,54] The illustration and utilization of the specific protein(s) involved in dsRNA processing and generation of siRNAs of various lengths could strongly benefit the further development of SIGS to control plant diseases caused by other pathogens. However, thanks to the diverse lengths of siRNAs in SIGS and the AGO protein binding bias in sRNA length, [55] whether or not any other proteins are involved in the last step of SIGS, i.e., the direct partner of siRNAs to bind mRNA and induce the unique translation inhibition in Phytophthora, remains to be further studied.…”

“…Western Blot: P. capsici strains CF1 or OG1 were inoculated after the spraying of relevant dsRNAs. Western blotting was performed according to the previous protocol [17] to identify the relative expression levels of the target proteins. Anti-3×FLAG or anti-GFP was used as the primary antibody, and β-tubulin was used as the internal control protein.…”

“…[16] CesA3 and OSBP1 were both found to be indispensable in Phytophthora since their knockout by CRISPR-Cas9 caused inevitable lethality (unpublished data in our laboratory), and they are efficient targets for P. capsici control through HIGS. [17] Thus, SIGS targeting of CesA3 and OSBP1 has great potential for the efficient control of Phytophthora.…”