Yule Liu, Yaru Lv, Jingjing Jian, Linyi Meng, Junxin Yan
Arbuscular mycorrhizal fungi (AMF) colonization influences plant-insect interactions, but the mechanisms underlying JA-mediated AMF-induced resistance remain unclear. Using rose as the experimental material, Rhizophagus intraradices inoculation combined with the jasmonic acid (JA) biosynthesis inhibitor SHAM was applied, integrating physiological measurements, hormone quantification, metabolomics, and insect bioassays to elucidate the role of JA-mediated secondary metabolites in AMF-induced resistance. The results showed that AMF colonization significantly increased JA levels and promoted the accumulation of flavonoid (37.21%) and total phenolic (15.38%), whereas SHAM treatment attenuated these responses. Feeding assays showed that larvae of Lymantria dispar exhibited reduced growth on mycorrhizal plants, while SHAM weakened this suppressive effect, suggesting that JA signaling may be involved in AMF-induced resistance. Metabolomic analysis revealed significant enrichment of flavonoid biosynthesis across treatments. Flavonoids, including naringenin, (-)-epicatechin, and kaempferide, were upregulated by AMF but reduced by SHAM. Correlation analysis showed that the contents of these metabolites were significantly positively correlated with JA levels, and negatively correlated with the growth of L. dispar larvae. Partial least squares structural equation modeling (PLS-SEM) provided statistical support for the hypothesized regulatory pathway, suggesting that AMF-induced resistance of rose against L. dispar may be associated with enhanced flavonoid accumulation in leaves, with JA potentially playing a regulatory role in this process (Goodness-of-fit = 0.79). This study provides a theoretical basis for sustainable pest management through AMF-plant symbiosis.