Krüppel-homologue 1regulates the development ofTuta absolutaand its cascade regulation pattern in the juvenile hormone signalling pathway

Abstract

Tomato leaf miner,Tuta absoluta(Meyrick), is one of the most destructive quarantine pests globally. It has been confirmed thatKrüppel-homologue 1(kr-h1) plays a key role in the regulation of juvenile hormone (JH). However, it is unclear howkr-h1regulates the synthesis of JH and its cascade regulation pattern in tomato leaf miner. Here, we obtained the six JH signalling genes (kr-h1,Methoprene-tolerant,Forkhead box O,Juvenile acid methyltransferase,Juvenile hormone esteraseandFatty acid synthase 2), and applied RNA interference to explore the role ofkr-h1and the seven genes (plusVitellogenin) regulation relationship inT. absoluta. Bioinformatics analysis revealed the structural characteristics of kr-h1 protein and JH receptor Met, which contained eight C2H2 zinc finger structures and three typical domains of the bHLH-PAS family, respectively. The expression levels ofMetandVgwere upregulated after RNAi ofkr-h1gene, while the gene levels ofJHAMTandFAS2were downregulated. Furthermore, topical application of JH analogue to second instar larvae could induce the expression ofkr-h1and inhibit the expression ofMet. Our study reveals the mechanism by whichkr-h1regulates JH pathway genes, which could be applied to control the growth of tomato leaf miners.