Genome-wide identification and expression patterns of uridine diphosphate (UDP)-glycosyltransferase genes in the brown planthopper, Nilaparvata lugens

Uridine diphosphate-glycosyltransferases (UGTs) are responsible for glycosylation by combining various small lipophilic molecules with sugars to produce water-soluble glycosides, which are crucial for the metabolism of plant secondary metabolites and detoxification in insects. This study presents a genome-wide analysis of the UGT gene family in the brown planthopper, Nilaparvata lugens, a destructive insect pest of rice in Asia. Based on the similarity to UGT homologs from other organisms, 20 putative NlUGT genes were identified in N. lugens. Sequence analysis revealed an average amino acid identity of 45.64 %; however, catalytic and sugar-binding residues, along with UGT signature motifs, were highly conserved. Phylogenetic analysis showed that the 20 NlUGTs were clustered into three main groups. The motif numbers ranged from 5 to 10, with motifs 1 and 4 being found in the functional domains of all 20 NlUGT proteins. Tandem and segmental duplication analysis identified one tandem duplication pair (UGT386K7 and UGT386K8) and two pairs of collinearity genes (UGT362C6/UGT386J4 and UGT386C2/UGT386G5) that expanded through segmental duplication within the UGT gene family of N. lugens. Combining the transcriptome and real-time quantitative PCR data showed that gut, antennae, integument, and ovaries were the tissues enriched with NlUGT gene expression. Six NlUGTs were present mainly in the gut, suggesting their putative roles in detoxification. This research provides valuable information on the molecular and genetic basis of NlUGTs, establishing a solid foundation for subsequent functional investigations of UGTs in planthopper, as well as paving the way for identifying potential targets to manage N. lugens effectively.