Recently, I have been doing experiments on plant stress response, involving salicylic acid (SA), jasmonic acid (JA), and methyl jasmonate (MeJA). I want to use inhibitors to specifically block their effects, so as to more clearly distinguish the specific functions of different hormones in the pathways.
But after reading some literature, I feel that there are not many reports on specific inhibitors for these hormones. I tried two of them myself, but the results were not ideal. For example, those targeting SA synthesis or signal transduction, or those that can effectively inhibit the effects of JA/MeJA!
Yan Yan Zhao Currently identified jasmonic acid (JA) signaling inhibitors mainly include lyn3 and SHAM.
Lyn3 binds tightly to the COI1 protein, interfering with the interaction between COI1 and JAZ proteins, thereby suppressing downstream responses of the JA signaling pathway, such as the transcription of JA-responsive genes. In tea plants, lyn3 reduces the accumulation of JA and JA-Ile, inhibits the expression of flavonoid biosynthesis genes (e.g., CsPAL, CsC4H), decreases the levels of defensive flavonoids such as (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), and ultimately lowers the resistance of tea plants to the tea geometrid (Ectropis grisescens).
SHAM primarily acts by blocking the biosynthesis pathway of JA, for example by inhibiting key enzymes like lipoxygenase, thereby reducing JA production. In contrast, lyn3 does not affect the expression of genes related to JA biosynthesis but directly disrupts the COI1-JAZ interaction.
Thus, these two inhibitors regulate the JA pathway through fundamentally different mechanisms (Ref.: PMID 35043181).
Regarding salicylic acid (SA) signaling inhibitors, PAMD and its derivative compounds are the main ones identified. PAMD significantly suppresses SA-induced expression of pathogenesis-related (PR) genes such as PR1, PR2, and PR5, blocks the SA-mediated systemic acquired resistance (SAR) pathway, and increases plant susceptibility to pathogens like Colletotrichum higginsianum (Ref.: PMID 26236918)
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