Identification of AHK2- and AHK3-like cytokinin receptors in Brassica napus reveals two subfamilies of AHK2 orthologues
Language English Country Great Britain, England Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
25336686
DOI
10.1093/jxb/eru422
PII: eru422
Knihovny.cz E-resources
- Keywords
- CHASE-containing His kinase, E. coli-based live-cell competitive receptor assay, JBnB library, gene structure, modular protein architecture, phylogenetic analysis,
- MeSH
- Brassica napus genetics metabolism MeSH
- Phylogeny MeSH
- Histidine Kinase MeSH
- Molecular Sequence Data MeSH
- Protein Kinases genetics metabolism MeSH
- Arabidopsis Proteins MeSH
- Gene Expression Regulation, Plant * MeSH
- Plant Proteins chemistry genetics metabolism MeSH
- Amino Acid Sequence MeSH
- Sequence Alignment MeSH
- Signal Transduction MeSH
- Protein Structure, Tertiary MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- AHK2 protein, Arabidopsis MeSH Browser
- AHK3 protein, Arabidopsis MeSH Browser
- Histidine Kinase MeSH
- Protein Kinases MeSH
- Arabidopsis Proteins MeSH
- Plant Proteins MeSH
Cytokinin (CK) signalling is known to play key roles in the regulation of plant growth and development, crop yields, and tolerance to both abiotic stress and pathogen defences, but the mechanisms involved are poorly characterized in dicotyledonous crops. Here the identification and functional characterization of sensor histidine kinases homologous to Arabidopsis CK receptors AHK2 and AHK3 in winter oilseed rape are presented. Five CHASE-containing His kinases were identified in Brassica napus var. Tapidor (BnCHK1-BnCHK5) by heterologous hybridization of its genomic library with gene-specific probes from Arabidopsis. The identified bacterial artificial chromosome (BAC) clones were fingerprinted and representative clones in five distinct groups were sequenced. Using a bioinformatic approach and cDNA cloning, the precise gene and putative protein domain structures were determined. Based on phylogenetic analysis, four AHK2 (BnCHK1-BnCHK4) homologues and one AHK3 (BnCHK5) homologue were defined. It is further suggested that BnCHK1 and BnCHK3, and BnCHK5 are orthologues of AHK2 and AHK3, originally from the B. rapa A genome, respectively. BnCHK1, BnCHK3, and BnCHK5 displayed high affinity for trans-zeatin (1-3nM) in a live-cell competitive receptor assay, but not with other plant hormones (indole acetic acid, GA3, and abscisic acid), confirming the prediction that they are genuine CK receptors. It is shown that BnCHK1 and BnCHK3, and BnCHK5 display distinct preferences for various CK bases and metabolites, characteristic of their AHK counterparts, AHK2 and AHK3, respectively. Interestingly, the AHK2 homologues could be divided into two subfamilies (BnCHK1/BnCK2 and BnCHK3/BnCHK4) that differ in putative transmembrane domain topology and CK binding specificity, thus implying potential functional divergence.
References provided by Crossref.org
Role of Cytokinins in Senescence, Antioxidant Defence and Photosynthesis
GENBANK
KF621024, KF621025, KF621026, KF621027, KF621028, KF621029, KF621030, KF621031, KF621032, KF621033
