1. An Arabidopsis mutant impaired in intracellular calcium elevation is sensitive to biotic and abiotic stress.
- Author
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Michal Johnson J, Reichelt M, Vadassery J, Gershenzon J, and Oelmüller R
- Subjects
- Abscisic Acid pharmacology, Alternaria chemistry, Alternaria drug effects, Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis growth & development, Arabidopsis Proteins genetics, Cell Wall drug effects, Cell Wall metabolism, Cytoplasm metabolism, Droughts, Genes, Plant, Germination drug effects, Glucosinolates metabolism, Indoles metabolism, Intracellular Space drug effects, Models, Biological, Mycelium chemistry, Mycelium drug effects, Plant Diseases microbiology, Plant Growth Regulators metabolism, Plant Roots metabolism, Plant Roots microbiology, Reactive Oxygen Species metabolism, Seedlings drug effects, Seedlings growth & development, Seedlings physiology, Sodium Chloride pharmacology, Spores, Fungal chemistry, Thiazoles metabolism, Calcium metabolism, Intracellular Space metabolism, Mutation genetics, Stress, Physiological drug effects
- Abstract
Background: Ca2+, a versatile intracellular second messenger in various signaling pathways, initiates many responses involved in growth, defense and tolerance to biotic and abiotic stress. Endogenous and exogenous signals induce cytoplasmic Ca2+ ([Ca2+]cyt) elevation, which are responsible for the appropriate downstream responses., Results: Here we report on an ethyl-methane sulfonate-mediated Arabidopsis mutant that fails to induce [Ca2+]cyt elevation in response to exudate preparations from the pathogenic mibrobes Alternaria brassicae, Rhizoctonia solani, Phytophthora parasitica var. nicotianae and Agrobacterium tumefaciens. The cytoplasmic Ca2+elevation mutant1 (cycam1) is susceptible to infections by A. brassicae, its toxin preparation and sensitive to abiotic stress such as drought and salt. It accumulates high levels of reactive oxygen species and contains elevated salicylic acid, abscisic acid and bioactive jasmonic acid iso-leucine levels. Reactive oxygen species- and phytohormone-related genes are higher in A. brassicae-treated wild-type and mutant seedlings. Depending on the analysed response, the elevated levels of defense-related compounds are either caused by the cycam mutation and are promoted by the pathogen, or they are mainly due to the pathogen infection or application of pathogen-associated molecular patterns. Furthermore, cycam1 shows altered responses to abscisic acid treatments: the hormone inhibits germination and growth of the mutant., Conclusions: We isolated an Arabidopsis mutant which fails to induce [Ca2+]cyt elevation in response to exudate preparations from various microbes. The higher susceptibility of the mutant to pathogen infections correlates with the higher accumulation of defense-related compounds, such as phytohormones, reactive oxygen-species, defense-related mRNA levels and secondary metabolites. Therefore, CYCAM1 couples [Ca2+]cyt elevation to biotic, abiotic and oxidative stress responses.
- Published
- 2014
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