Light regulated expression of sensor histidine kinase CKI1 controls cytokinin related development Journal Article

Author(s): Dobisova, Tereza; Hrdinova, Vendula; Cuesta Moliner, Candela; Michlickova, Sarka; Urbankova, Ivana; Hejatkova, Romana; Žádníková, Petra; Pernisová, Markéta; Benková, Eva; Hejátko, Jan
Article Title: Light regulated expression of sensor histidine kinase CKI1 controls cytokinin related development
Affiliation IST Austria
Abstract: In plants, the multistep phosphorelay (MSP) pathway mediates a range of regulatory processes, including those activated by cytokinins. The crosstalk between cytokinin response and light is known for a long time. However, the molecular mechanism underlying the interactionbetween light and cytokinin signaling remains elusive. In the screen for upstream regulators we identified a LONG PALE HYPOCOTYL (LPH) gene whose activity is indispensable for spatiotemporally correct expression of CYTOKININ INDEPENDENT-1 (CKI1), encoding the constitutively active sensor histidine kinase that activates MSP signaling. lph is a new allele of HEME OXYGENASE 1 (HY1) which encodes the key protein in the biosynthesis of phytochromobilin, a cofactor of photoconvertiblephytochromes. Our analysis confirmed the light-dependent regulation oftheCKI1 expression pattern. We show that CKI1 expression is under the control of phytochrome A (phyA), functioning as a dual (both positive and negative) regulator of CKI1 expression, presumably via the phyA-regulated transcription factors PHYTOCHROME INTERACTING FACTOR 3 (PIF3) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1). Changes in CKI1 expression observed in lph/hy1-7 and phy mutants correlatewithmisregulation of MSP signaling, changedcytokinin sensitivity and developmental aberrations,previously shown to be associated with cytokinin and/or CKI1 action. Besides that, we demonstrate novel role of phyA-dependent CKI1 expression in the hypocotyl elongation and hook development during skotomorphogenesis. Based on these results, we propose that the light-dependent regulation of CKI1 provides a plausible mechanistic link underlying the well-known interaction between light- and cytokinin-controlled plant development.
Journal Title: Plant Physiology
Volume: 174
Issue 1
ISSN: 1532-2548
Publisher: American Society of Plant Biologists  
Date Published: 2017-05-17
Start Page: 387
End Page: 404
Copyright Statement: 2017 American Society of Plant Biologists. All rights reserved.
DOI: 10.1104/pp.16.01964
Notes: This research has been financially supported by the Ministry of Education, Youth and 69 Sports of the Czech Republic under the project CEITEC 2020 (LQ1601) and 70 LM2015062 Czech-BioImaging and the Czech Science Foundation (projects 15-122000S and 13-39982S). Corresponding author: Jan Hejatko, We thank Dr. Enrique Lopéz Juéz (Royal Holloway University of London) for providing the hy1.62 and hy1-100 mutant lines, Pablo Cerdán for providing us with the double phyA phyB and hextuple phyA-E/ft mutant lines, and Bruno Mueller for the TCSn:GFP line and TCS:LUC construct. We also thank Hana Zimová for her valuable help and technical assistance, and Dr. Stephen Hunt (Qubit Systems, Canada) for careful reading of the manuscript, his revisions, and valuable comments.
Open access: no