Reduction in Gonad Development and Sperm Motility in Male Brown Planthopper Nilaparvata lugens via RNAi-Mediated Knockdown of tramtrack

The brown planthopper <i>Nilaparvata lugens</i>, a major rice pest, threatens global food security through rapid reproduction. This study investigates the role of the <i>tramtrack</i> (<i>ttk</i>) gene in male reproductive development and spermatogenesis using RNA interference (RNAi). Gene expression analysis revealed higher <i>ttk</i> levels in testes. RNAi-mediated knockdown of <i>ttk</i> in fourth-instar male nymphs reduced its expression by up to 80%, leading to severely impaired gonad development. Testes, vas deferens, and accessory glands in treated males exhibited 8-89% volume reductions compared to controls, accompanied by a 51-69% decline in sperm count and 60-85% reduction in sperm motility. Consequently, eggs fertilized by treated males showed a 73% decrease in hatching rates, with arrested embryonic development. These findings demonstrate <i>ttk</i>'s critical role in spermatogenesis and gonad maturation in <i>N. lugens</i>, highlighting its potential as an RNAi target for sustainable pest control strategies.