Phosphatidic acid mediates salt stress response by regulation of MPK6 in Arabidopsis thaliana.
• Phospholipase D (PLD) hydrolyzes phospholipids to produce phosphatidic acid (PA) and a head group, and is involved in the response to various environmental stresses, including salinity. Here, we determined the roles of PLDα and PA in the mediation of salt (NaCl)-stress signaling through the regulation of mitogen-activated protein kinase (MAPK or MPK) in Arabidopsis thaliana. • NaCl-induced changes in the content and composition of PA were quantitatively profiled by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). A specific PA species (a MAPK 16:0-18:2 PA), which was increased in abundance by exposure to NaCl, bound to a MPK6, according to filter binding and ELISA. The effect of PA on MPK6 activity was tested using in-gel analysis. • 16:0-18:2 PA stimulated the activity of MPK6 immunoprecipitated from Arabidopsis leaf extracts. Treatment with NaCl induced a transient activation of MPK6 in wild-type plant, but the activation was abolished in the pldα1 plant mutant. A plasma membrane Na(+)/H(+) antiporter (SOS1) was identified as a downstream target of MPK6. MPK6 phosphorylated the C-terminal fragment of SOS1. The MPK6 phosphorylation of SOS1 was stimulated by treatment with NaCl, as well as directly by PA. • These results suggest that PA plays a critical role in coupling MAPK cascades in response to salt stress.
Yu
Lijuan
L
College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Nie
Jianing
J
Cao
Chunyan
C
Jin
Yakang
Y
Yan
Min
M
Wang
Fuzheng
F
Liu
Ji
J
Xiao
Yun
Y
Liang
Yongheng
Y
Zhang
Wenhua
W
D017360:Arabidopsis / Q000201:enzymology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002462:Cell Membrane; D017343:Genes, Plant; D048053:Mitogen-Activated Protein Kinase 6 / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010712:Phosphatidic Acids / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism; D010766:Phosphorylation; D018515:Plant Leaves; D055049:Salt Tolerance / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D012965:Sodium Chloride / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D013312:Stress, Physiological
D029681:Arabidopsis Proteins; D010712:Phosphatidic Acids; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride; D048053:Mitogen-Activated Protein Kinase 6; D010739:Phospholipase D