Cytokinin perception in potato: new features of canonical players.

Sergey N Lomin,Dmitry V Arkhipov,Ekaterina M Savelieva,Oksana O Kolachevskaya,Irina A Getman,Dmitry I Osolodkin,Georgy A Romanov,Yulia A Myakushina

doi:10.1093/jxb/ery199

Abstract

Potato is the most economically important non-cereal food crop. Tuber formation in potato is regulated by phytohormones, cytokinins (CKs) in particular. The present work studied CK signal perception in potato. The sequenced potato genome of doubled monoploid Phureja was used for bioinformatic analysis and as a tool for identification of putative CK receptors from autotetraploid potato cv. Désirée. All basic elements of multistep phosphorelay required for CK signal transduction were identified in the Phureja genome, including three genes orthologous to three CK receptor genes (AHK 2-4) of Arabidopsis. As distinct from Phureja, autotetraploid potato contains at least two allelic isoforms of each receptor type. Putative receptor genes from Désirée plants were cloned, sequenced and expressed, and the main characteristics of encoded proteins were determined, in particular their consensus motifs, modelled structure, ligand-binding properties, and ability to transmit CK signals. In all studied aspects the predicted sensor histidine kinases met the requirements for genuine CK receptors. Expression of potato CK receptors was found to be organ-specific and sensitive to growth conditions, particularly to sucrose content. Our results provide a solid basis for further in-depth study of CK signaling system and biotechnological improvement of potato.

Highlights

Potato is a widespread practically important crop, its tuber formation is controlled by phytohormones
Potato has everything necessary for CK signaling via the multistep phosphorelay (MSP) pathway
The search for protein sequences and encoding genes involved in CK signaling was performed on the basis of the duplicated potato monoploid Phureja genome (Potato Genome Sequencing Consortium, 2011)

Summary

Introduction

Potato is a widespread practically important crop, its tuber formation is controlled by phytohormones (reviewed in Aksenova et al, 2012, 2014). Previous studies have shown that cytokinins (CKs) and auxins can accelerate and enhance potato tuber formation (Aksenova et al, 2000; Romanov et al, 2000; Roumeliotis et al, 2012; Kolachevskaya et al, 2015, 2017; Wang et al, 2018). In non-tuberizing plants (tobacco, tomato), increased doses of active CKs stimulate morphogenesis, in many aspects resembling tuber formation (Guivarc'h et al, 2002; Eviatar-Ribak et al, 2013). Elevated doses of CKs affect the overall architectonics of potato plants, suppressing the root development (Aksenova et al, 2000). All the above indicates the important role of CKs in both the formation of tubers and the general development and resistance of potato plants

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Conclusion