Open AccessThe Protein Kinase CK2 Mediates Cross-Talk between Auxin- and Salicylic Acid-Signaling Pathways in the Regulation of PINOID Transcription
Author(s) -
Laia Armengot,
Eleonora Caldarella,
María Mar Marquès-Bueno,
M. Carmen Martínez
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0157168
Subject(s) - arabidopsis , microbiology and biotechnology , auxin , transcription factor , biology , transcription (linguistics) , transcriptional regulation , arabidopsis thaliana , protein kinase a , kinase , regulation of gene expression , biochemistry , gene , mutant , linguistics , philosophy
The protein kinase CK2 is a ubiquitous and highly conserved enzyme, the activity of which is vital for eukaryotic cells. We recently demonstrated that CK2 modulates salicylic acid (SA) homeostasis in Arabidopsis thaliana , and that functional interplay between CK2 and SA sustains transcriptional expression of PIN-FORMED ( PIN ) genes. In this work, we show that CK2 also plays a key role in the transcriptional regulation of PINOID ( PID ), an AGC protein kinase that modulates the apical/basal localization of auxin-efflux transporters. We show that PID transcription is up-regulated by auxin and by SA and that CK2 is involved in both pathways. On the one hand, CK2 activity is required for proteosome-dependent degradation of AXR3, a member of the AUX/IAA family of auxin transcriptional repressors that must be degraded to activate auxin-responsive gene expression. On the other hand, the role of CK2 in SA homeostasis and, indirectly, in SA-driven PID transcription, was confirmed by using Arabidopsis NahG transgenic plants, which cannot accumulate SA. In conclusion, our results evidence a role for CK2 as a functional link in the negative cross-talk between auxin- and SA-signaling.