Interfering with calcineurin induces mortality and imposes substantial fitness costs in Helicoverpa armigera

Calcineurin (CaN), a Ca²⁺-dependent serine/threonine protein phosphatase belonging to the protein phosphatase 2B (PP2B) family, plays diverse regulatory roles in various physiological and biochemical pathways in vivo.

To investigate its potential as a key target gene for RNA interference (RNAi)-based pesticide development, this study conducted CaN RNAi on 4^th instar Helicoverpa armigera and statistically analyzed their mortality, body weight, pupation rate, eclosion rate and other life indicators.

The results showed that injection of CaN dsRNA significantly reduced both CaN gene expression and the enzymatic activity of CaN protein. Following knocking down CaN expression, about 60.81% mortality was observed among the fourth-instar larvae. Moreover, the body weight of surviving larvae showed a significant reduction starting 24 h after CaN dsRNA administration. The developmental durations from 4^th instar larva to pupa and from pupa to adult eclosion were significantly prolonged. Both pupation and eclosion rates were markedly decreased, with the final eclosion rate dropping to only 3.75%.

These findings demonstrate that CaN is essential for the growth and development of H. armigera and highlight its potential as a promising RNAi target for pest control strategies.