Oberemok, V. | Search bioRxiv

bioRxiv2024

Antisense DNA acaricide targeting pre-rRNA of two-spotted spider mite Tetranychus urticae as efficacy-enhancing agent of fungus Metarhizium robertsii

Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most dangerous pests in the world and one of the most pesticide-resistant species ever. Complex biological preparations are of great interest for the acaricide market because they do not poison ecosystems and do not bioaccumulate in food products, simultaneously, pests more slowly develop resistance to complex preparations. In this study we applied complex bioformulation composed of 11-mer antisense oligonucleotide (oligonucleotide acaricide or DNA acaricide) Tur-3 and fungus Metarhizium robertsii for T. urticae control. We discovered that joint contact application of DNA acaricide and fungus M. robertsii significantly attenuates reproduction rate of the mite. Our results indicate that DNA acaricide Tur-3 and fungus M. robertsii act synergistically and lead to a significant 7-times elevated mortality rate and 5-times reduced fecundity of the mite. Oligonucleotide acaricide Tur-3 causes 2,5-fold re-duction of expression of the target pre-rRNA of T. urticae and suppresses the activity of key players of detoxifying enzymes of its defense system (phenoloxidase, esterase, glutathione-S-transferase), on average, by 2-3 times. Oligonucleotide acaricide Tur-3 interferes with protein biosynthesis causing decrease in production of defense system enzymes of the pest. Obviously, attenuation of defense system enhances fungal infection or/and fungus produces a variety of enzymes that degrade and destroy the integument structure of the pest, aiding the penetration of oligonucleotide acaricide Tur-3. This research article is the first evidence of successful application of oligonucleotide acaricide together with fungus M. robertsii for efficient T. urticae control. Combined application of oligonucleotide acaricides based on conservative antisense sequences of rDNA of pests and fungi is a potent and selective approach for eco-friendly plant protection.

molecular biology↗

bioRxiv2024

Oligonucleotide insecticides (contact unmodified antisense DNA biotechnology) and RNA biocontrols (double-stranded RNA technology): newly born fraternal twins in plant protection

Recent advances in molecular genetics, nucleic acid synthesis, and bioinformatics have pro-vided novel opportunities for plant protection against insect pests. Currently, both DNA and RNA serve as active insecticidal ingredients, transcending their traditional role as carriers of genetic information. This novel activity is achieved through two fundamentally distinct mechanisms: DNA containment (DNAc), employing oligonucleotide insecticides based on contact unmodified antisense DNA biotechnology (CUADb), also known as genetic zipper technology, and RNA interference (RNAi), employing RNA biocontrols based on double-stranded RNA (dsRNA) technology. The investigation of the molecular mechanism underlying the antisense activity of nucleic acids emerged in the early 1960s. While the antisense function of RNA in gene silencing through interference (RNAi) has been documented in the late1990s as an antiviral immune response in nematodes, the CUADb antisense approach initially emerged as a powerful strategy for pest control against lepidopterans in 2008. CUADb approach relies on disrupting rRNA biogenesis and ribosome production, a process entirely distinct from RNAi. The efficacy of these approaches appears to be species dependent: while CUADb demonstrates optimal activity against Sternorrhyncha (e.g., aphids, mealybugs, psyllids, scale insects), thrips, and mites, RNAi strategy shows a strong insecticidal potential against beetles from the Tenebrionidae and Chrysomelidae families. Here, we will review the differences between the two technologies, their mechanism of action and the current challenges facing their adoption.

molecular biology↗