Impact of spermidine- derived phenolamides treatment on the symbiotic microbiota composition of Nilaparvata lugens and Spodoptera frugiperda

16S RNA sequencing showed that Nilaparvata lugens and Spodoptera frugiperda fed on spd-PAs-enrich plants disrupted the symbiotic microbial composition, increasing the abundance of Acinetobacter. Acinetobacter, which is capable of metabolizing spd-PAs, and its increased abundance in Nilaparvata lugens is associated with higher mortality. Additionally, spd-PAs exhibited strong antifungal activity against YLS. Collectively, our findings reveal that spd-PAs function both as direct insecticidal compounds and as disruptors ofNilaparvata lugens and Spodoptera frugiperda symbiotic microbiota, offering new insights into plant-herbivore-microbe interactions and potential strategies for developing pest-resistant crops.