Studies On The Potential Relationship Between The Protein Kinase SIK1 And The Jasmonate Pathway In Arabidopsis

The Hippo pathway is a core signaling pathway in negatively regulating the organ size in animals.In the past fifteen years,extensive studies have been made on the pathway,from the discovery of the core proteins and subsequent establishment of regulatory networks,to the study of its physiological and pathological functions.Our lab had previously identified the Arabidopsis protein kinase SIK1 as a functional orthologue for Hippo,and established the SIK1-MOB1 module as corresponding to the Hpo-Mats module.We also speculated that SIK1 may be involved in the jasmonate(JA)pathway.Here I explored the possible relationship between SIK1 and the JA pathway.I discovered both the seed germination and the primary root elongation of sik1-4 null mutant are hypersensitive to exogenous JA.RNA sequencing and quantitative real-time fluorescence PCR indicated that the transcript levels of JA synthesis and signal genes were mostly downregulated in sik1-4.A polyclonal antibody against SIK1 was successfully raised,with which the protein level of SIK1 was confirmed to be JA-inducible.In order to identify interacting partners for SIK1,the transgenic lines carrying SIK1-GFP were obtained and used for co-immunoprecipitate-mass spectrometry analysis.Finally,to explore the possible genetic interaction between SIK1 and JA pathways,sik1-4 was crossed with various JA synthesis and signaling mutants.In summary,links between SIK1 and JA have been uncovered in this study,whereas the mechanisms still remain to be explored.This study serves as a basis for the future establishment of a complete plant Hippo pathway.