MED18 interaction with distinct transcription factors regulates multiple plant functions.
Mediator is an evolutionarily conserved transcriptional regulatory complex. Mechanisms of Mediator function are poorly understood. Here we show that Arabidopsis MED18 is a multifunctional protein regulating plant immunity, flowering time and responses to hormones through interactions with distinct transcription factors. MED18 interacts with YIN YANG1 to suppress disease susceptibility genes glutaredoxins GRX480, GRXS13 and thioredoxin TRX-h5. Consequently, yy1 and med18 mutants exhibit deregulated expression of these genes and enhanced susceptibility to fungal infection. In addition, MED18 interacts with ABA INSENSITIVE 4 and SUPPRESSOR OF FRIGIDA4 to regulate abscisic acid responses and flowering time, respectively. MED18 associates with the promoter, coding and terminator regions of target genes suggesting its function in transcription initiation, elongation and termination. Notably, RNA polymerase II occupancy and histone H3 lysine tri-methylation of target genes are affected in the med18 mutant, reinforcing MED18 function in different mechanisms of transcriptional control. Overall, MED18 conveys distinct cues to engender transcription underpinning plant responses.
Department of Botany and Plant Pathology, Purdue University, 915 W State Street, West Lafayette, Indiana 47907, USA.
Zhibing
Z
Lai
1] Department of Botany and Plant Pathology, Purdue University, 915 W State Street, West Lafayette, Indiana 47907, USA [2].
Craig M
CM
Schluttenhofer
Bioinformatics Core, Cyber Center, Discovery Park, Purdue University, 155 South Grant Street, West Lafayette, Indiana 47907, USA.
Ketaki
K
Bhide
Bioinformatics Core, Cyber Center, Discovery Park, Purdue University, 155 South Grant Street, West Lafayette, Indiana 47907, USA.
Jacob
J
Shreve
Bioinformatics Core, Cyber Center, Discovery Park, Purdue University, 155 South Grant Street, West Lafayette, Indiana 47907, USA.
Jyothi
J
Thimmapuram
Division of Applied Life Sciences (BK 21 program), Gyeongsang National University, Jinju 660-701, Korea.
Sang Yeol
SY
Lee
Division of Applied Life Sciences (BK 21 program), Gyeongsang National University, Jinju 660-701, Korea.
Dae-Jin
DJ
Yun
Department of Botany and Plant Pathology, Purdue University, 915 W State Street, West Lafayette, Indiana 47907, USA.
Tesfaye
T
Mengiste
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D056892:Mediator Complex / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000502:physiology; D010937:Plant Growth Regulators / Q000502:physiology*; D057865:Plant Immunity / Q000502:physiology*; D012319:RNA Polymerase II / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*; D050986:YY1 Transcription Factor / Q000502:physiology
C470421:ABI4 protein, Arabidopsis; D029681:Arabidopsis Proteins; C582268:MED18 protein, Arabidopsis; D056892:Mediator Complex; D026901:Membrane Transport Proteins; C510826:PTR3 protein, Arabidopsis; D010937:Plant Growth Regulators; C517314:SUF4 protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; D050986:YY1 Transcription Factor; D012319:RNA Polymerase II