Interaction Between Arabidopsis Receptor Protein Kinase Tmk And Fer And Its Genetic And Biochemical Analysis Of ABA Signalling

Previous studies have found that the receptor-like protein kinase Transmembrane Kinase(TMK)plays a vital role in the growth and development of plants.For example,the root becomes shorter,the rosette leaves become smaller,and the fertility is severely reduced.Recent studies have shown that receptor-like protein kinase TMK4 interacts with TAA1(a key enzyme for auxin synthesis)through phosphorylation,thereby negatively regulating the biosynthesis of auxin.This is also the first report on the post-translational regulatory mechanism of auxin.This shows that in order to meet the various needs of the plant growth process,there are multiple mechanisms to regulate the biosynthesis of auxin.Auxin has duality to plant growth,high concentration inhibits growth,low concentration promotes growth.Taking the apical hook of Arabidopsis cotyledon as an example,it was found that high concentrations of auxin can induce the shearing of TMK1 protein,and the sheared TMK1 protein transmits the auxin signal from the outside of the cell to the cytoplasm and nucleus and ultimately regulates the downstream response of auxin.Does TMK protein kinase also respond to other plant hormones besides auxin? How does he participate in regulation? Studies have shown that the receptor-like protein kinase FERONIA(FER)interacts with ABI2 protein phosphatase through phosphorylation,and then participates in the ABA signal pathway.What kind of connection is there between these two receptor-like protein kinases? Based on the above scientific issues,this thesis has carried out a series of studies with the help of physiological and biochemical methods.The specific results include the following aspects:(1)TMK1/4 interacted with the members of PP2 CA included ABI1/2,HAB1/2 by yeast screen.And TMK1/4 interacted with ABI1/2 at PM in Arabidopsis protoplast,through Y2 H,Bi FC,pull-down and Co-IP assays.(2)Through biochemistry analysis that TMK4 phosphorylated ABI2 in vitro and in vivo.The phosphorylation sites were Ser139,Ser140,Ser266.(3)phosphatase activity analysis that TMK4 enhanced the activity of ABI2 by phosphorylation and negatively regulated ABA signaling pathway.And tmk4 mutants were sensitive in respond to ABA at cotyledons green,stomata aperture and root elongation.(4)TMK1/4 interacted with FER at PM in Arabidopsis protoplast,through Y2 H,Bi FC,pull-down and Co-IP assays.And TMK1/4 and FER can phosphorylate each other.(5)Using a variety of biochemical experiments(including Y2 H,Bi FC,Pull-down,Co-IP)proved that: TMK1/4 can interact with FER and can phosphorylate each other.(6)Through genetic analysis found that the fer-4 mutant is similar to the tmk1/4double mutant in growth-related phenotypes included rosette size,plant height and seed fertility.