Knockdown of two trehalose‐6‐phosphate synthases severely affects chitin metabolism gene expression in the brown planthopper Nilaparvata lugens

BACKGROUND RNA interference combined with digital gene expression (DGE) analysis can be used to study gene function. Trehalose‐6‐phosphate synthase (TPS) plays a key role in the synthesis of trehalose and insect development. RESULTS DGE analysis revealed that the expression of nine or four chitinase genes was reduced significantly 48 h after NlTPS1 and NlTPS2 knockdown by RNAi, respectively. Additionally, abnormal phenotypes were noted, and approximately 30% of insects died. HK and G6PI2 expression decreased significantly whereas GFAT, GNPNA and UAP expression increased significantly 72 h after NlTPS1 and NlTPS2 knockdown. PGM1 expression decreased significantly after TPS2 knockdown, whereas PGM2 expression increased significantly and the expression of three CHS genes decreased 48 h after TPS1 knockdown. The mRNA expression of all 12 chitin degradation genes decreased 48 h after NlTPS1 and NlTPS2 treatment, and Cht2, Cht3, Cht6, Cht7, Cht10 and ENGase levels remained significantly decreased up to 72 h after NlTPS1 and NlTPS2 knockdown. CONCLUSIONS These results demonstrate that silencing of TPS genes can lead to increased moulting deformities and mortality rates owing to the misregulation of genes involved in chitin metabolism, and TPS genes are potential pest control targets in the future. © 2016 Society of Chemical Industry