MINPP : a conserved salivary effector family diversified by gene duplication promotes insect feeding while activating plant defense

Abstract BACKGROUND Insect salivary proteins play critical roles in modulating plant defenses and facilitating feeding, yet the evolutionary origins and functional mechanisms of most salivary effectors remain poorly understood. This study investigates the evolution and function of multiple inositol polyphosphate phosphatases (MINPPs), the enzymes that specifically expanded in planthopper and bean bug. RESULTS Phylogenetic analysis revealed that MINPP genes have undergone lineage‐specific multiplication in planthoppers, with up to six paralogs per species. Multiplicated MINPPs exhibited pronounced salivary gland‐biased expression, including NlMINPP1b/2b, LsMINPP1b/2b, SfMINPP1b/2b and RpMINPP2b, whereas LsMINPP2c showed ovary‐biased expression. RNAi‐mediated silencing of salivary gland‐biased MINPPs in Nilaparvata lugens , Laodelphax striatellus and Riptortus pedestris consistently reduced honeydew excretion, decreased fecundity and prolonged developmental duration in treated insects, indicating the importance of these genes. However, when secreted into plants, salivary MINPPs appear to trigger host defense responses. In Nicotiana tabacum plants, transient expression of MINPPs activated callose deposition and suppressed whitefly performance, whereas in rice plants, overexpressing LsMINPP2b likewise reduced planthopper fecundity and honeydew excretion. CONCLUSION MINPPs represent a conserved enzyme family that has diversified through gene duplication to acquire salivary gland‐biased expression in a few insects. However, when secreted into plants, MINPPs potentially activate host defenses and reduce insect performance. These findings provide new insights into the evolutionary diversification of insect salivary effectors and highlight MINPPs as potential molecular targets for developing novel pest control strategies. © 2026 Society of Chemical Industry.