Graphene oxide enhances aphid resistance in sorghum via the miR319-SbTCP7-SbLOX3 Pathway.

The aphid (Melanaphis sacchari) has emerged as a formidable pest, devastating sorghum plants and highlighting the need for sustainable management strategies. Graphene oxide (GO), as a novel material, has garnered attention for its use in crop cultivation and management, but its effects on biotic stresses remain elusive. Here, we used 10 mg/L GO to spray aphid-stressed sorghum seedlings four times in total. GO exposure reduced 50% H2O2 from the reactive oxygen species (ROS) burst induced by the aphid. Further analysis revealed that GO within the cells acts as a nanozyme, mimicking and enhancing the catalytic activity of the ROS-scavenging system to maintain ROS homeostasis, protecting normal plant growth and development under aphid stress. Moreover, the moderate increase in H2O2 in GO-treated, aphid-infected seedlings blocked the biogenesis of miR319, leading to the induction of its target gene SbTCP7, which in turn activated the transcription of SbLOX3, a rate-limiting enzyme in jasmonic acid (JA) biosynthesis. Subsequent molecular and genetic assays confirmed that the miR319-SbTCP7 module enhances JA metabolism, promoting the accumulation of JA and its active derivative jasmonic acid-isoleucine (JA-Ile) to combat aphids. Our results suggest that GO, as a potential nanozyme, enhances the aphid resistance of sorghum through the miR319-SbTCP7 module to regulate JA synthesis, indicating a novel cultivation strategy for improving pest management via nanomaterials. This frontier research has opened new avenues for crop protection against invasive pests like aphids.