Host plants expressing pxy-miR-34-5p demonstrate high efficacy against multiple lepidopterous pests

Lepidopteran pests are destructive pests and have evolved significant resistance to many insecticides. Alternative green control strategies are urgently needed. Our previous research had revealed that overexpression or knockdown of a Plutella xylostella microRNA, pxy-miR-34-5p, could lead to high mortality and severe developmental defects in multiple lepidopteran pests, thus has great potential in lepidopteran pests control. Here, pxy-miR-34-5p was successfully expressed in cruciferous plants, Arabidopsis thaliana and Brassica campestris. Feeding on leaves of transgenic miR-34-5p rape significantly reduced the expression of ecdysone receptor gene PxEcR of P. xylostella by 56.8–70.2%. Bioassays results demonstrated that compared to that of the larvae fed on wild type Arabidopsis, the accumulated mortalities of P. xylostella fed on transgenic miR-34-5p Arabidopsis were significantly increased by 34.9%–52.0%. After feeding on transgenic miR-34-5p rape leaves for four to six days, the highest accumulated corrected mortalities of P. xylostella, Spodoptera frugiperda and Spodoptera exigua larvae reached 100.0%, 94.1%, and 100.0%, respectively. These results indicated that insect microRNAs can be used to control multiple target pests by constructing transgenic crops, which lays an important foundation for the further development of miRNA-based green pest control strategies.