Potent and selective 'genetic zipper' method for plant protection: innovative DNA psyllidicides against Trioza alacris Flor based on short unmodified antisense oligonucleotides targeting rRNA of the pest

Abstract

Chemical insecticides increased the chemical burden on natural ecosystems posing environmental health risk factor. The urgent need for a more sustainable and ecological approach has produced many innovative ideas, including eco-friendly genetic zipper method (or CUAD platform) based on contact oligonucleotide insecticides. Oligonucleotide insecticides have enjoyed success recently on many sternorrhynchans showing highly adaptable structure for distinct insect pest species and selective mode of action. In this article, we describe the efficiency of the oligonucleotide insecticides (briefly, olinscides or DNA insecticides) Alacris-11 and Laura-11, as well as their combined use in mixture (1:1), designed for control of bay sucker (Trioza alacris Flor), an important psyllid pest of noble laurel (Laurus nobilis L.). These olinscides are based on short unmodified antisense DNA oligonucleotides that target ITS2 between 5.8S rRNA and 28S rRNA in pre-rRNA (Laura-11) and 28S rRNA region in mature 28S rRNA and pre-rRNA (Alacris-11). The maximum pest mortality, observed on 14th day of the experiment, comprised 95.01 {+/-} 4.42 % for Alacris-11, 97.16 {+/-} 2.48 % for Laura-11, and 98.72 {+/-} 1.14 % for their mixture (1:1). The control oligonucleotide CTGA-11 did not cause any significant mortality (9.38 {+/-} 0.57 %), emphasizing selectivity in the action of oligonucleotide insecticides. The results show potent and specific nature of oligonucleotide insecticides for pest control and opens up new frontiers in control of economically important psyllids in agriculture and forestry, including Asian citrus psyllid (Diaphorina citri Kuwayama) and many others. Scientists can easily adopt genetic zipper method for plethora of insect pests because DNA is a programmable molecule and provides game-changing characteristics for plant projection.