Functional Studies on the Integument Structure and Fatty Acid Synthesis of Brown Planthopper by NlFAD3

Fatty acid desaturase (FAD) serves as a pivotal enzyme in the lipid synthesis pathway, regulating fatty acid unsaturation levels in insects through catalytic activity. While FAR, another crucial enzyme in the same pathway, has been demonstrated to influence the integument architecture of the brown planthopper (BPH), the functional role of FAD in this biological process remains insufficiently explored. In the present investigation, we systematically identified 10 NlFAD family genes through bioinformatics analysis and subsequently characterized their expression patterns using real-time quantitative polymerase chain reaction (RT-qPCR). Through integrated approaches combining RNA interference (RNAi), transmission electron microscopy (TEM), and targeted fatty acid metabolomics, we elucidated the regulatory effects of NlFAD silencing on both integument ultrastructure and fatty acid biosynthesis in BPH. Key findings revealed that NlFAD3 knockdown induced: Silencing of NlFAD3 resulted in a significant increase in the mortality rate of BPH, the highest percentage of moulting deaths, the phenomenon of significant disruption of its integument structure, and a significant increase in the content of BPH stearic acid. This study provides a new research idea for the search of effective target genes to realize the effective control of BPH.