Rice blast-induced jasmonic acid signal transduction affects rice resistance against brown planthopper by regulating the flavonoid biosynthesis pathway

The complex interactions among plants, herbivorous insects, and microbes form an iron triangle in nature, and even a minor alteration in any of these components can trigger a chain of interconnected reactions. In our study on the interaction between rice plants, brown planthopper (BPH), and rice blast fungus, we discovered that the resistance of rice treated with rice blast to BPH was significantly increased. Transcriptomic and mass spectrometric results showed that rice blast fungus treatment induced the contents of eriodictyol, naringenin, quercetin, as well as the expression of most genes in the flavonoid biosynthesis pathway except OsF3'H . Correspondingly, OsF3′H knockout lines enhanced rice resistance to BPH. OsMYC2 is a core transcription factor in the jasmonic acid (JA) signaling pathway and rice blast fungus induced the expression of OsMYC2 , OsMYC2 knockout lines reduced rice resistance to BPH. Furthermore, a series of experiments demonstrated that OsMYC2 has a transcriptional repressive effect on OsF3'H . Overall, we revealed the phenomena and reasons behind the increased resistance to BPH after treating rice with rice blast fungus in terms of histological data, experimental phenotypes, and gene expression, respectively. This will deepen our understanding of the interactions among rice, rice fungus and BPH, and provide theoretical support for ecological management.