Terpenoids are important compounds associated with the pest and herbivore resistance mechanisms of plants; consequently, it is essential to identify and explore terpene synthase (TPS) genes in maize. In the present study, we identified 31 TPS genes based on a pan-genome of 26 high-quality maize genomes containing 20 core genes (present in all 26 lines), seven dispensable genes (present in 2 to 23 lines), three near-core genes (present in 24 to 25 lines), and one private gene (present in only 1 line). Evaluation of ka/ks values of TPS in 26 varieties revealed that TPS25 was subjected to positive selection in some varieties. Six ZmTPS had ka/ks values less than 1, indicating that they were subjected to purifying selection. In 26 genomes, significant differences were observed in ZmTPS25 expression between genes affected by structural variation (SV) and those not affected by SV. In some varieties, SV altered the conserved structural domains resulting in a considerable number of atypical genes. The analysis of RNA-seq data of maize Ostrinia furnacalis feeding revealed 10 differentially expressed ZmTPS, 9 of which were core genes. However, many atypical genes for these responsive genes were identified in several genomes. These findings provide a novel resource for functional studies of ZmTPS.

The response of Spodoptera frugiperda genes toward insecticides is crucial for guiding insecticide use. The regulation of the S. frugiperda genes via long noncoding RNAs (lncRNAs) under insecticide treatment should be investigated. In this study, 452 differentially expressed lncRNAs were identified by analyzing RNA-sequencing data of S. frugiperda under 23 pesticide treatments. We found 59 and 43 differentially expressed lncRNAs that could regulate detoxification-related cytochrome P450 and UDP-glucuronosyltransferase genes, respectively. Furthermore, the target genes of differentially expressed lncRNAs were enriched in Pfam, including chitin bind 4 and gene ontology terms such as structural constituent of the cuticle, revealing their potential mechanism of action on the growth inhibition of S. frugiperda larvae. Insecticide-specific expression of lncRNAs highlights the properties and commonalities of different insecticide-induced lncRNA regulatory mechanisms. To conclude, the results of this study provide new insights and perspectives on the use of 23 insecticides via lncRNA regulation of mRNAs.