Identification of salivary proteins in the rice leaf folder Cnaphalocrocis medinalis by transcriptome and LC-MS/MS analyses.

Salivary proteins in the oral secretion (OS) of chewing insects play a crucial role in insect-plant interactions during feeding. The rice leaf folder Cnaphalocrocis medinalis, a notorious pest in global rice production, triggers defense responses during feeding, but little is known about its salivary proteins. In this study, we confirmed that C. medinalis releases OS during feeding. By employing transcriptomic analysis and liquid chromatography-tandem mass spectroscopy (LC-MS/MS), we examined the salivary proteins from labial salivary glands and OS from C. medinalis. A total of 14,397 genes were expressed at the RNA level and 229 salivary proteins were identified. Comparative analysis with other 25 arthropod species revealed that 43 proteins were unique to C. medinalis. Expression pattern analysis revealed that most of the selected genes were highly expressed in the gut and the larval stages (4th-5th instar). These findings provide a comprehensive resource for future functional studies of salivary proteins, offering new insights into the molecular mechanisms by which C. medinalis modulates plant defenses and potential applications in pest management.