Spatially Distributed Cytokinins: Metabolism, Signaling, and Transport

Jiangzhe Zhao; Jingqi Wang; Jie Liu; Penghong Zhang; Guzel Kudoyarova; Chang-Jun Liu; Kewei Zhang

doi:10.1016/j.xplc.2024.100936

Spatially Distributed Cytokinins: Metabolism, Signaling, and Transport

Plant Commun. 2024 Apr 30:100936. doi: 10.1016/j.xplc.2024.100936. Online ahead of print.

Authors

Jiangzhe Zhao¹, Jingqi Wang¹, Jie Liu¹, Penghong Zhang¹, Guzel Kudoyarova², Chang-Jun Liu³, Kewei Zhang⁴

Affiliations

¹ Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China.
² Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya 69, Ufa 450054, Russia.
³ Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
⁴ Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, PR China. Electronic address: kwzhang@zjnu.edu.cn.

PMID: 38689499
DOI: 10.1016/j.xplc.2024.100936

Abstract

Cytokinins are a type of mobile phytohormone that regulate plant growth, development, and environmental adaptability. The major cytokinin species include isopentenyl adenine (iP), trans-zeatin (tZ), cis-zeatin (cZ), and dihydrozeatin (DZ). The spatial distributions of different cytokinin species in different organelles, cells, tissues, and organs are primarily shaped by biosynthesis via isopentenyltransferases (IPT), cytochrome P450 monooxygenase, and 5'-ribonucleotide phosphohydrolase, and by conjugation or catabolism via glycosyltransferase or cytokinin oxidase/dehydrogenase (CKX). Cytokinins bind to histidine receptor kinases (HKs) in the endoplasmic reticulum (ER) or plasma membrane (PM) and relay signals to response regulators (RRs) in the nucleus by shuttle proteins known as histidine phosphotransfer proteins (HPs). The movements of cytokinins from sites of biosynthesis to signal perception sites usually require long-distance, intercellular, and intracellular transport. In the past decade, ATP-binding cassette (ABC) transporters, purine permeases (PUP), AZA-GUANINE RESISTANT (AZG) transporters, equilibrative nucleoside transporters (ENT), and Sugars Will Eventually be Exported Transporters (SWEET) have been characterized as involved in cytokinin transport processes. This review begins by introducing the spatial distributions of various cytokinins and the subcellular localizations of the proteins involved in cytokinin metabolism and signaling. Highlights focus on an inventory of the characterized transporters involved in cytokinin compartmentalization, including long-distance, intercellular, and intracellular transport, and the regulation of spatial distributions of cytokinins by environmental cues. Future directions for cytokinin research are also discussed.

Keywords: biosynthesis; cytokinin; environmental changes; signaling transduction; transporter.

Publication types

Review