Molecular and functional analysis of phosphoacetylglucosamine mutase (PAGM) and Glucose-6-phosphate isomerase (G6PI) gene in the white-backed planthopper Sogatella furcifera (Hemiptera: Delphacidae).

The white-backed planthopper (Sogatella furcifera) is a devastating piercing-sucking pest endangering rice production. Genes in the chitin synthesis pathway are critical for its molting and development, representing potential targets for targeted control. This study cloned the full-length cDNAs of SfPAGM (KY381946) and SfG6PI (KY695112) from S. furcifera using RACE-PCR, and systematically explored their molecular characteristics and physiological functions via bioinformatics analysis, qPCR-based spatiotemporal expression detection, and RNAi verification. SfPAGM (ORF 1632 bp, encoding 543 amino acids) and SfG6PI (ORF 1662 bp, encoding 553 amino acids) shared 88% and 89% identity with homologs in Nilaparvata lugens, respectively, showing evolutionary conservation in Delphacidae. Both genes were ubiquitously expressed across the life cycle, with peak expression in newly molted instars and emergent adults, and were most highly expressed in the epidermis but lowest in the head. RNAi results showed that SfPAGM dsRNA reduced gene expression by 84% at 72 h, leading to 37.3% mortality in 5 days with molting defects (e.g., old cuticle cracking, wing malformation). SfG6PI dsRNA suppressed expression to 58.8% of the control, resulting in 41.3% mortality (5-day survival rate 58.7%) with lethal phenotypes like double-layered cuticle and wing shrinkage. This study confirms the indispensable roles of SfPAGM and SfG6PI in S. furcifera’s molting and growth, providing insights into insect chitin synthesis mechanisms and a theoretical basis for RNAi-based targeted control technologies.