Table 3.
Application of external RNAs for plant fungal resistance.
| Target | RNA Treatment | RNA Amount | RNA and Fungal Application | Plant Host | Effect Assessment | Effect Maintenance | Reference |
|---|---|---|---|---|---|---|---|
| CYP51A, CYP51B, and CYP51C genes of Fusarium graminearum | In vitro synthesized CYP3-dsRNA (791 bp); siRNAs produced from dsRNA by RNAse III | 10 μg dsRNA or siRNA per plate with six detached leaves (20 ng/μL in 500 µL of water) | RNA spraying; fungal inoculation 48 hpt | Barley | Inhibition of fungal growth and weaker disease symptoms; suppression of target fungal CYP51 mRNAs | At least for 6 dpi | Koch et al. (2016) [13] |
| DCL1 and DCL2 genes of Botrytis cinerea | In vitro synthesized dsRNA (490 bp); siRNAs produced in vitro from the dsRNA by RNAse III | 20 µL of RNA (20 ng/µL) per each plant specimen | RNA dropped onto the surface of each plant specimen; fungal inoculation or inoculation 1, 3, and 5 dpt | Tomato, strawberry, grape, lettuce, onion, rose, Arabidopsis | Inhibition of fungal growth and weaker disease symptoms; supression of fungal DCL transcripts | At least for 5 dpi | Wang et al. (2016) [14] |
| 59 target genes of Sclerotinia sclerotiorum | In vitro synthesized 20 dsRNAs (200–450 bp) | 10–25 μL of 200–500 ng dsRNA and 0.02–0.03% Silwet L-77 | Foliar RNA application to the leaf surface with Silwet L-77; fungal inoculation after leaf drying | Oilseed rape, Arabidopsis | Of the 59 dsRNAs tested, 20 showed antifungal activity against S. sclerotiorum and B. cinerea and weaker disease symptoms; suppression of fungal target genes | At least for 2–4 dpi | McLoughlin et al. (2018) [15] |
| Myosin 5 gene of Fusarium asiaticum | In vitro synthesized dsRNA (496 bp) | 0.1 pM Myo5 dsRNA | RNA spraying; fungal inoculation 12 hpt | Wheat | Antifungal activity and weaker disease symptoms; reduction of fungal resistance to phenamacril fungicide; suppression of fungal Myo5 transcript levels | Up to 7 dpi (Myo5-dsRNA); Up to 14 dpi (Myo5-dsRNA plus phenamacril) | Song et al. (2018a) [16] |
| β2Tub gene of Fusarium asiaticum | In vitro synthesized dsRNA (489 bp) | 30–40 ng/µL | RNA spraying after leaf wounding with quartz sand; fungal inoculation 12 hpt | Cucumber, soya, barley, wheat | Antifungal activity against F. asiaticum, B. cinerea, Magnaporthe oryzae, and Colletotrichum truncatum and weaker disease symptoms; reduction of F. asiaticum resistance to carbendazim fungicide | Up to 7 dpi (β2Tub–dsRNA); up to 14 dpi (β2Tub-dsRNA plus carbendazim) | Gu et al. (2019) [18] |
CYP51—cytochrome P450 lanosterol C-14 α-demethylase; dpi—days post infection; dpt—days post treatment; hpt—hours post treatment; DCL—Dicer-like protein; β2Tub—β2 –tubulin.