Identification of Potential RNAi Targets for Cotton Mealybug (Phenacoccus solenopsis Tinsley) Management

Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), commonly known as the cotton mealybug, is a highly invasive pest worldwide, particularly in tropical and subtropical regions. Despite posing a significant economic threat to various agricultural crops, a promising, environmentally friendly control strategy against this pest is lacking. Furthermore, the molecular aspects of this insect pest remain understudied. This pioneering study provides the first proteome data for four different developmental stages of the cotton mealybug. A comparative analysis of differential protein expression (DEPs) among six groups revealed the highest number of DEPs (550 up-regulated and 1118 down-regulated) when comparing the egg and first nymphal stages to the second nymphal instar (fold change ≥ 2, P < 0.05). From the generated proteomics data, potential target genes were identified for cotton mealybug management. These genes were further evaluated for RNAi-based pest control and optimization of the dsRNA delivery system in cotton mealybug. Notably, RNAi-based pest management analysis revealed that dsRNA of the Ferritin-like precursor (Psfer) gene (TRINITY_DN17055_c1_g1_i1) induced significant mortality (~ 69%), followed by dsRNA of the probable cytochrome P450 6a14-like (Psp450 6a14) gene (TRINITY_DN47081_c0_g1) and odorant-binding protein 2 precursor (Psobp) gene (TRINITY_DN11547_c0_g1). This investigation proposes a potential alternative, eco-friendly strategy for managing cotton mealybug populations and related pests. Furthermore, this study provides valuable insights into the proteome of the cotton mealybug and Hemiptera, offering avenues for proteome-based identification of RNAi targets for pest management and crop improvement.