Modifications of Sphingolipid Content Affect Tolerance to Hemibiotrophic and Necrotrophic Pathogens by Modulating Plant Defense Responses in Arabidopsis

• Published in: Plant physiology (Bethesda) 2015-11, Vol.169 (3), p.2255-2274
• Main Authors: Magnin-Robert, Maryline, Le Bourse, Doriane, Markham, Jonathan, Dorey, Stéphan, Clément, Christophe, Baillieul, Fabienne, Dhondt-Cordelier, Sandrine
• Format: Article
• Language: English
• Subjects: American culture; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - microbiology; Arabidopsis - physiology; Biology; Botrytis; Botrytis - physiology; Cell Death; Cyclopentanes - metabolism; Infections; Isoleucine - analogs & derivatives; Isoleucine - metabolism; Leaves; Life Sciences; Mutation; Oxylipins - metabolism; Pathogens; Plant cells; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Growth Regulators - metabolism; Plants; Pseudomonas syringae - physiology; Reactive Oxygen Species - metabolism; Salicylic Acid - metabolism; Signal Transduction; SIGNALING AND RESPONSE; Sphingolipids; Sphingolipids - metabolism; Sphingosine - analogs & derivatives; Sphingosine - metabolism
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.15.01126

Sphingolipids are emerging as second messengers in programmed cell death and plant defense mechanisms. However, their role in plant defense is far from being understood, especially against necrotrophic pathogens. Sphingolipidomics and plant defense responses during pathogenic infection were evaluated in the mutant of long-chain base phosphate (LCB-P) lyase, encoded by thedihydrosphingosine-1-phosphate lyase1(AtDPL1) gene and regulating long-chain base/LCB-P homeostasis.Atdpl1mutants exhibit tolerance to the necrotrophic fungusBotrytis cinereabut susceptibility to the hemibiotrophic bacteriumPseudomonas syringaepvtomato(Pst). Here, a direct comparison of sphingolipid profiles in Arabidopsis (Arabidopsis thaliana) during infection with pathogens differing in lifestyles is described. In contrast to long-chain bases (dihydrosphingosine [d18:0] and 4,8-sphingadienine [d18:2]), hydroxyceramide and LCB-P (phytosphingosine-1-phosphate [t18:0-P] and 4-hydroxy-8-sphingenine-1-phosphate [t18:1-P]) levels are higher inAtdpl1-1than in wild-type plants in response toB. cinerea. FollowingPstinfection, t18:0-P accumulates more strongly inAtdpl1-1than in wild-type plants.Moreover, d18:0 and t18:0-P appear as key players inPst- andB. cinerea-induced cell death and reactive oxygen species accumulation. Salicylic acid levels are similar in both types of plants, independent of the pathogen. In addition, salicylic acid-dependent gene expression is similar in both types ofB. cinerea-infected plants but is repressed inAtdpl1-1after treatment withPst. Infection with both pathogens triggers higher jasmonic acid, jasmonoyl-isoleucine accumulation, and jasmonic acid-dependent gene expression inAtdpl1-1mutants. Our results demonstrate that sphingolipids play an important role in plant defense, especially toward necrotrophic pathogens, and highlight a novel connection between the jasmonate signaling pathway, cell death, and sphingolipids.