1-MCP Triggering Coffee Anthesis and Its Effects on Binding Affinity and Gene Expression of Different Ethylene Receptors

Ethylene is a pivotal regulator of coffee anthesis, and 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, offers a potential to manage flowering in coffee plants. This study aimed to identify the effect of 1-MCP on gene expression of ethylene receptors, and compare the interaction in silico between 1-MCP and different ethylene receptors to understand what could be associated with coffee anthesis promotion by this molecule. The study involved phenotypic characterization, ethylene quantification, RNA expression profiling, phylogenetic analysis, homology modeling, and molecular docking. Results revealed that 1-MCP accelerated floral bud development to anthesis within 12 days, contrasting with water treated floral buds which exhibited progress just after a rainfall event. Moreover, 1-MCP application notably increased ethylene levels in both leaves and floral buds. Gene expression analysis indicated that 1-MCP modulates ethylene related gene expression differently in leaves and floral buds. Decreasing the expression of signaling genes in floral buds (CaERS1-like, ETR2-like, ETR4-like and EIN4-like), increasing it in leaves (ETR1-like, ETR2-like, ETR4-like and CaCTR1-like); and increasing the expression of CaACO3-like (biosynthesis related gene) in floral buds. Molecular docking studies suggested that ethylene may exhibit a higher affinity for receptors with lower interaction energy with 1-MCP. In conclusion, 1-MCP could be a promising tool to promote anthesis in coffee trees by modulating ethylene related processes, as the interaction between 1-MCP and ethylene receptors may influence ethylene sensitivity through different modulation of gene expression in leaves and floral buds.