Unraveling the Role of Cuticular Protein 3-like (HvCP3L) in the Chitin Pathway through RNAi and Methoxyfenozide Stress Response in Heortia vitessoides Moore.

Simple Summary: The insect epidermis covers multiple parts of the insect body, fulfilling both structural and protective roles. Primarily composed of chitin and epidermal proteins, the insect epidermis displays considerable diversity among insects. The CPR family, the largest and most diverse group of cuticular protein (CP) genes identified to date, plays crucial roles in insect development, including body length regulation and cuticle formation. Steroid hormones, such as ecdysteroids, regulate the expression of epidermal proteins. In addition, the insecticide Methoxyfenozide mimics the action of 20E, thereby affecting insect growth. Our study on Heortia vitessoides Moore elucidates the role of HvCP3L and offers novel insights into pest management strategies for Aquilaria sinensis (Lour.) Spreng. Cuticle proteins (CPs) constitute a multifunctional family; however, the physiological role of Cuticle Protein 3-like (CP3L) in Heortia vitessoides Moore remains largely unclear. In this study, we cloned the HvCP3L gene from the transcriptional library of Heortia vitessoides Moore. RT-qPCR results revealed that HvCP3L exhibited high expression levels during the larval stage of Heortia vitessoides Moore, particularly at the L5D1 stage, observed in both larval and adult heads. Through RNA interference, we successfully silenced the HvCP3L gene, resulting in a significant reduction in the survival rate of Heortia vitessoides Moore, with the survival rate from larvae to adults plummeting to a mere 17.7%, accompanied by phenotypic abnormalities. Additionally, we observed that the knockdown of HvCP3L led to the inhibition of genes in the chitin pathway. Following exposure to methoxyfenozide stress, the HvCP3L gene exhibited significant overexpression, coinciding with phenotypic abnormalities. These findings underscore the pivotal role of HvCP3L in the growth and development of Heortia vitessoides Moore. [ABSTRACT FROM AUTHOR]