A strong NF-κB p65 responsive cis-regulatory sequence from Arabidopsis thaliana interacts with WRKY40

Area of Science:

• Plant molecular biology
• Immunology
• Bioinformatics

Background:

• Transcription factors play crucial roles in innate immunity in both mammals and plants.
• Microbe-associated molecular patterns (MAMPs) trigger immune responses through specific sequence recognition.

Purpose of the Study:

• To investigate the interaction of mouse NF-κB p65 with MAMP-responsive sequences in Arabidopsis thaliana.
• To identify and characterize novel MAMP-responsive elements and their binding factors in plants.

Main Methods:

• Yeast one-hybrid screening to identify interacting proteins.
• Reporter gene assays in plant cells to measure transcriptional activation.
• Bioinformatic analysis to predict transcription factor binding sites.

Main Results:

• A specific sequence from the Arabidopsis thaliana gene At1g76960 strongly activated NF-κB p65 dependent reporter gene expression in plant cells.
• Three putative NF-κB p65 binding sites within this sequence were essential for activation and binding.
• The MAMP responsivity of this sequence was enhanced by introducing a GCC-box.
• Arabidopsis thaliana WRKY40, a transcriptional repressor, was identified and binds to the TTTTCTA sequence, similar to known WRKY binding motifs.

Conclusions:

• Mammalian NF-κB and plant WRKY transcription factors exhibit similar binding site recognition mechanisms.
• Conserved sequence recognition pathways in innate immunity exist between mammals and plants.
• The identified Arabidopsis thaliana sequence represents a novel MAMP-responsive element with implications for understanding plant immunity.