AtCRK5 Protein Kinase Exhibits a Regulatory Role in Hypocotyl Hook Development during Skotomorphogenesis

Abu Baba, Imran and Andrási, Norbert and Valkai, Ildiko and Gorcsa, Teréz and Koczka, Lilla and Darula, Zsuzsanna and Medzihradszky F., Katalin and Szabados, László and Fehér, Attila and Rigó, Gábor and Cséplő, Ágnes (2019) AtCRK5 Protein Kinase Exhibits a Regulatory Role in Hypocotyl Hook Development during Skotomorphogenesis. INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 20 (14). ISSN 1661-6596


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Seedling establishment following germination requires the fine tuning of plant hormone levels including that of auxin. Directional movement of auxin has a central role in the associated processes, among others, in hypocotyl hook development. Regulated auxin transport is ensured by several transporters (PINs, AUX1, ABCB) and their tight cooperation. Here we describe the regulatory role of the Arabidopsis thaliana CRK5 protein kinase during hypocotyl hook formation/opening influencing auxin transport and the auxin-ethylene-GA hormonal crosstalk. It was found that the Atcrk5-1 mutant exhibits an impaired hypocotyl hook establishment phenotype resulting only in limited bending in the dark. The Atcrk5-1 mutant proved to be deficient in the maintenance of local auxin accumulation at the concave side of the hypocotyl hook as demonstrated by decreased fluorescence of the auxin sensor DR5::GFP. Abundance of the polar auxin transport (PAT) proteins PIN3, PIN7, and AUX1 were also decreased in the Atcrk5-1 hypocotyl hook. The AtCRK5 protein kinase was reported to regulate PIN2 protein activity by phosphorylation during the root gravitropic response. Here it is shown that AtCRK5 can also phosphorylate in vitro the hydrophilic loops of PIN3. We propose that AtCRK5 may regulate hypocotyl hook formation in Arabidopsis thaliana through the phosphorylation of polar auxin transport (PAT) proteins, the fine tuning of auxin transport, and consequently the coordination of auxin-ethylene-GA levels.

Item Type: Article
Additional Information: Funding Agency and Grant Number: Tempus Public Foundation, Hungary; Biological Doctoral School University of Szeged, Hungary; OTKA PD project [115502, PD128055]; OTKA [124828, NN118089]; Hungarian Ministry for National Economy [GINOP-2.3.2-15-2016-00001] Funding text: This research was supported by the Tempus Public Foundation, Hungary and the Biological Doctoral School University of Szeged, Hungary for A.I.B., by OTKA PD project No. 115502 and No. PD128055 for G.R., by OTKA grant No. 124828 for I.V., A.C. and A.F., by OTKA grant No. NN118089 for G.R., A.C., L.S., by the Hungarian Ministry for National Economy GINOP-2.3.2-15-2016-00001 for A.I.B., A.C., G.R., I.V., N.A., A.F., Z.D., K.F.M., L.S. Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Szeged, 6720, Hungary Agricultural Biotechnology Institute, Szent-Györgyi Albert u. 4, Gödöllő, H-2100, Hungary Developmental and Cell Biology of Plants, CEITEC Masaryk University, Brno, 62500, Czech Republic Department of Plant Biology, University of Szeged, 52. Közép fasor, Szeged, H-6726, Hungary Export Date: 3 October 2019 Correspondence Address: Rigó, G.; Institute of Plant Biology, Biological Research Centre, Hungarian Academy of SciencesHungary; email:
Uncontrolled Keywords: ETHYLENE; Arabidopsis thaliana; Skotomorphogenesis; Ca2+/calmodulin-dependent kinase-related kinases (CRKs), polar auxin transport (PAT) proteins; GA3; auxin gradient;
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3015 Molecular biology / molekuláris biológia
Q Science / természettudomány > QK Botany / növénytan
Depositing User: MTMT SWORD
Date Deposited: 21 Nov 2019 12:36
Last Modified: 21 Nov 2019 12:36

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