Phosphatidic acid mediates salt stress response by regulation of MPK6 in Arabidopsis thaliana

Abstract

• 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.

Quantitative expression analysis of drought responsive genes in clones of Hevea with varying levels of drought tolerance

“…MAPK signaling triggers expression of a cascade of genes that are involved in cellular protection, desiccation tolerance, ROS scavenging enzymes and DNA damage repair by activating corresponding transcription factors (Neill et al 2002a, b;Hung et al 2005;Desikan et al 2000). Involvement of MAPKs in abiotic stress adaptation has been widely reported in many plant species (Yu et al 2010;Ning et al 2010 The transcript abundance of Nuclear Factor Y subunit A (NFYA) was found more in RRIM 600 and RRII 105 while it was moderate in RRII 208. But it got slightly down regulated in RRII 414.…”

MAPK cascades and major abiotic stresses

“…Recently, Hoang et al (2012) have reported that the MAP kinase MPK6 activates, and interacts with, MYB41 and results in enhanced salt tolerance in Arabidopsis. In addition, the regulation of MPK6 by the phosphatidic acid (PA) under salt stress suggests that MPK6 and PA may function in the same signaling pathway in response to salt stress (Yu et al 2010).…”

SALT-RESPONSIVE ERF1 Regulates Reactive Oxygen Species-Dependent Signaling during the Initial Response to Salt Stress in Rice

“…Moreover, the mkk2 mutant exhibits a salt-sensitive phenotype (Teige et al, 2004). A downstream target of MPK6 is the Na + /H + antiporter Salt Overly Sensitive1 (SOS1), a major regulator of ion homeostasis under salt stress (Shi et al, 1999;Yu et al, 2010). Furthermore, deregulated expression of MAPK genes alters the expression of salt stress-related TFs (KishiKaboshi et al, 2010;Kong et al, 2011).…”