Comparative Antennal Transcriptome Analysis of Phenacoccus solenopsis and Expression Profiling of Candidate Odorant Receptor Genes

Insects rely heavily on olfaction to regulate essential behaviors such as host location, oviposition and mating. The invasive cotton mealybug, <i>Phenacoccus solenopsis</i> Tinsley represents a global threat to cotton and numerous cultivated crops. To elucidate the molecular basis of its olfaction mechanisms, we sequenced and assembled antennal transcriptomes from male and female adults using Illumina NovaSeq X Plus technology. Among 13,891 unigenes, 91 chemosensory genes were identified, including 40 odorant receptors, 13 gustatory receptors, 19 ionotropic receptors, 10 odorant-binding proteins, 7 chemosensory proteins, and 2 sensory neuron membrane proteins. Differential expression analysis revealed 6312 genes with significant sex-biased expression between male and female antennae, including 55 chemosensory genes. Phylogenetic analyses further clarified the evolutionary relationships of these chemosensory genes with homologs from other hemipteran species. Notably, validation confirmed that 18 <i>PsolORs</i> were male-biased. This comprehensive transcriptomic study establishes a foundation for further functional characterization of pheromone reception and provides valuable candidate genes for dissecting chemoreception mechanisms in <i>P. solenopsis</i>.