Identification of Carboxylesterase Genes and Function of Three Inducible α-Esterase Genes Involved in Insecticidal Activity of α-Solanine in Phthorimaea operculella

Carboxylesterases (CarEs) play an important role in the detoxification of exogenous toxic compounds in insects. However, the effect of Phthorimaea operculella CarEs (PoCarEs) on the insecticidal activity of α-solanine, a potato-derived secondary metabolite, remains unclear. In this study, we identified 96 PoCarEs. Phylogenetic analysis demonstrated that PoCarEs could be classified into nine clades, with an abundance of α-esterases. Their chromosome distribution and sequence characterization were also performed. Expression profiles of PoCarE genes revealed functional diversities in tissues and larval guts across different developmental stages. PoCarE activity increased following α-solanine exposure and mediated the insecticidal activity of α-solanine. α-solanine exposure increased the expression of Poae2, Poae21, and Poae25, and knockdown of these genes increased the insecticidal activity of α-solanine against larvae. Moreover, homology modeling and molecular docking results suggested that Poae2, Poae21, and Poae25 proteins exhibit effective affinities for α-solanine. These results provide valuable insights into how insects cope with α-solanine toxicity, facilitating the development of an efficient management strategy for this and other pests.