Molecular characterization of cytokinin-responsive histidine kinases in maize. Differential ligand preferences and response to cis-zeatin

Keiko Yonekura-Sakakibara, Mikiko Kojima, Tomoyuki Yamaya, Hitoshi Sakakibara

Research output: Contribution to journalArticlepeer-review

156 Citations (Scopus)

Abstract

Genes for cytokinin-responsive His-protein kinases (ZmHK1, ZmHK2, and ZmHK3a) were isolated from maize (Zea mays). Heterologous expression of each of the ZmHKs in Escherichia coli having the ΔrcsC and cps::lacZ genetic background conferred cytokinin-inducibility of lacZ expression on the bacteria. In the recombinant E. coli system, ZmHK1 and ZmHK3a were more sensitive to free-base cytokinins than to the corresponding nucleosides; isopentenyladenine was most effective for ZmHK1, while ZmHK2 tended to be most sensitive to trans-zeatin and the riboside. In contrast to a known cytokinin receptor of Arabidopsis (AHK4/CRE1/WOL), all ZmHKs responded to cis-zeatin (cZ), which generally is believed to be inactive or only weakly active. In cultured maize cells, expression of ZmRR1, a cytokinin-inducible response regulator, was induced by cZ as well as by trans-zeatin. These results strongly suggest that maize cytokinin receptors differ in ligand preference, and that cZ is an active cytokinin at least in maize.

Original languageEnglish
Pages (from-to)1654-1661
Number of pages8
JournalPlant physiology
Volume134
Issue number4
DOIs
Publication statusPublished - 2004 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

Fingerprint

Dive into the research topics of 'Molecular characterization of cytokinin-responsive histidine kinases in maize. Differential ligand preferences and response to cis-zeatin'. Together they form a unique fingerprint.

Cite this