The 30th International Conference on Arabidopsis Research (ICAR 2019)

665 / 2019-04-30 13:21:35

Transcriptional co-regulation of MYB46 and WRKY33 by ANGUSTIFOLIA modulates Arabidopsis resistance towards biotrophic and necrotrophic pathogens

ANGUSTIFOLIA, biotrophic pathogen, necrotrophic pathogen, transcriptional regulation

Plenary track > Systems Biology

The primary role of ANGUSTIFOLIA (AN), designated as C-TERMINAL BINDING PROTEIN (CtBP), is the transcriptional co-repression of tumor suppressor and pro-apoptotic genes in mammals. However, the nuclear function of AN remains unstudied in plants. Here, we demonstrated that AN can accumulate in the nucleus and functions as a transcriptional repressor. By interacting with another nuclear protein TYROSYL-DNA PHOSPHODIESTERASE1 (TDP1), AN imposes transcriptional repression on MYB46 which encodes a key transcription factor regulating phenylpropanoid biosynthesis, while releasing the TDP1-imposed transcriptional repression on WRKY33 which encodes a transcription factor regulating the ethylene/jasmonic acid (ET/JA) signaling pathway. Consistent with these molecular and biochemical results, genetic analyses of Arabidopsis mutants and transgenic plants demonstrated that AN regulates the expressions of WRKY33, MYB46, as well as their downstream genes involved in salicylic acid (SA) and ET/JA signaling pathways and that AN alters plant defense capability against biotrophic and necrotrophic pathogens. Collectively, these findings suggest that AN functions as a transcriptional repressor to co-regulate the expression of MYB46 and WRKY33 to modulate plant defenses against biotrophic and necrotrophic pathogens.