Arabidopsis MAP kinase 4 regulates salicylic acid- and jasmonic acid/ethylene-dependent responses via EDS1 and PAD4

TY - JOUR

T1 - Arabidopsis MAP kinase 4 regulates salicylic acid- and jasmonic acid/ethylene-dependent responses via EDS1 and PAD4

AU - Brodersen, Klaus Peter

AU - Petersen, Morten

AU - Nielsen, Henrik Bjørn

AU - Zhu, Shijiang

AU - Newman, Mari-Anne

AU - Shokat, Kevan M.

AU - Rietz, Steffen

AU - Parker, Jane

AU - Mundy, John

PY - 2006

Y1 - 2006

N2 - Arabidopsis MPK4 has been implicated in plant defense regulation because mpk4 knockout plants exhibit constitutive activation of salicylic acid (SA)-dependent defenses, but fail to induce jasmonic acid (JA) defense marker genes in response to JA. We show here that mpk4 mutants are also defective in defense gene induction in response to ethylene (ET), and that they are more susceptible than wild-type (WT) to Alternaria brassicicola that induces the ET/JA defense pathway(s). Both SA-repressing and ET/JA-(co)activating functions depend on MPK4 kinase activity and involve the defense regulators EDS1 and PAD4, as mutations in these genes suppress de-repression of the SA pathway and suppress the block of the ET/JA pathway in mpk4. EDS1/PAD4 thus affect SA-ET/JA signal antagonism as activators of SA but as repressors of ET/JA defenses, and MPK4 negatively regulates both of these functions. We also show that the MPK4-EDS1/PAD4 branch of ET defense signaling is independent of the ERF1 transcription factor, and use comparative microarray analysis of ctr1, ctr1/mpk4, mpk4 and WT to show that MPK4 is required for induction of a small subset of ET-regulated genes. The regulation of some, but not all, of these genes involves EDS1 and PAD4.

AB - Arabidopsis MPK4 has been implicated in plant defense regulation because mpk4 knockout plants exhibit constitutive activation of salicylic acid (SA)-dependent defenses, but fail to induce jasmonic acid (JA) defense marker genes in response to JA. We show here that mpk4 mutants are also defective in defense gene induction in response to ethylene (ET), and that they are more susceptible than wild-type (WT) to Alternaria brassicicola that induces the ET/JA defense pathway(s). Both SA-repressing and ET/JA-(co)activating functions depend on MPK4 kinase activity and involve the defense regulators EDS1 and PAD4, as mutations in these genes suppress de-repression of the SA pathway and suppress the block of the ET/JA pathway in mpk4. EDS1/PAD4 thus affect SA-ET/JA signal antagonism as activators of SA but as repressors of ET/JA defenses, and MPK4 negatively regulates both of these functions. We also show that the MPK4-EDS1/PAD4 branch of ET defense signaling is independent of the ERF1 transcription factor, and use comparative microarray analysis of ctr1, ctr1/mpk4, mpk4 and WT to show that MPK4 is required for induction of a small subset of ET-regulated genes. The regulation of some, but not all, of these genes involves EDS1 and PAD4.

KW - Former LIFE faculty

KW - hormone interactions, MAP kinase, pathogen responses

U2 - 10.1111/j.1365-313X.2006.02806.x

DO - 10.1111/j.1365-313X.2006.02806.x

M3 - Journal article

C2 - 16813576

SN - 0960-7412

VL - 47

SP - 532

EP - 546

JO - Plant Journal

JF - Plant Journal

IS - 4

ER -