Arabidopsis thaliana natural variation reveals connections between UV radiation stress and plant pathogen-like defense responses

• Published in: Plant physiology and biochemistry 2015-08, Vol.93, p.34-43
• Main Authors: Piofczyk, Thomas, Jeena, Ganga, Pecinka, Ales
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - biosynthesis; Arabidopsis Proteins - genetics; Gene Expression Regulation, Plant - radiation effects; Genome-wide association studies; Mutation; Natural variation; Radiation Tolerance - genetics; Radiation Tolerance - radiation effects; RNA-sequencing; Stress, Physiological - genetics; Stress, Physiological - radiation effects; Ultraviolet Rays; UV radiation
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2015.01.011

UV radiation is a ubiquitous component of solar radiation that affects plant growth and development. Here we studied growth related traits of 345 Arabidopsis thaliana accessions in response to UV radiation stress. We analyzed the genetic basis of this natural variation by genome-wide association studies, which suggested a specific candidate genomic region. RNA-sequencing of three sensitive and three resistant accessions combined with mutant analysis revealed five large effect genes. Mutations in PHE AMMONIA LYASE 1 (PAL1) and putative kinase At1g76360 rendered Arabidopsis hypersensitive to UV stress, while loss of function from putative methyltransferase At4g22530, NOVEL PLANT SNARE 12 (NPSN12) and defense gene ACTIVATED DISEASE RESISTANCE 2 (ADR2) conferred higher UV stress resistance. Three sensitive accessions showed strong ADR2 transcriptional activation, accumulation of salicylic acid (SA) and dwarf growth upon UV stress, while these phenotypes were much less affected in resistant plants. The phenotype of sensitive accessions resembles autoimmune reactions due to overexpression of defense related genes, and suggests that natural variation in response to UV radiation stress is driven by pathogen-like responses in Arabidopsis. •Extensive variation to UV radiation stress exists among Arabidopsis accessions.•Our analysis revealed five genes causing altered UV sensitivity.•Natural variation to UV stress provides links to plant pathogen defense.