title: AtCPK1 calcium-dependent protein kinase mediates pathogen resistance in Arabidopsis.
abstract: In mammals, lipid bodies play a key role during pathological and infectious diseases. However, our knowledge on the function of plant lipid bodies, apart from their role as the major site of lipid storage in seed tissues, remains limited. Here, we provide evidence that a calcium-dependent protein kinase (CPK) mediates pathogen resistance in Arabidopsis. AtCPK1 expression is rapidly induced by fungal elicitors. Loss-of-function mutants of AtCPK1 exhibit higher susceptibility to pathogen infection compared to wild-type plants. Conversely, over-expression of AtCPK1 leads to accumulation of salicylic acid (SA) and constitutive expression of SA-regulated defence and disease resistance genes, which, in turn, results in broad-spectrum protection against pathogen infection. Expression studies in mutants affected in SA-mediated defence responses revealed an interlocked feedback loop governing AtCPK1 expression and components of the SA-dependent signalling pathway. Moreover, we demonstrate the dual localization of AtCPK1 in lipid bodies and peroxisomes. Overall, our findings identify AtCPK1 as a component of the innate immune system of Arabidopsis plants.
authors.affiliation: Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB, Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Coca
authors.forename: Blanca
authors.initials: B
authors.lastname: San Segundo
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005658:Fungi / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D020869:Gene Expression Profiling; D017343:Genes, Plant; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D059467:Transcriptome; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; D011494:Protein Kinases; D020156:Salicylic Acid; C490306:ATCDPK1 protein, Arabidopsis; D017871:Calcium-Calmodulin-Dependent Protein Kinases