The AHK4 gene involved in the cytokinin-signaling pathway as a direct receptor molecule in Arabidopsis thaliana.
We previously identified a set of structurally related genes, AHK2, 3 and 4, each encoding a sensor histidine kinase in Arabidopsis thaliana. To determine the relevant biological functions, we identified a loss-of-function mutation of the AHK4 gene. The mutant exhibited the cytokinin-resistant phenotype not only in inhibition of root growth by cytokinin but also in greening and shoot induction of calli. Moreover, AHK4 expressed in budding yeast showed histidine kinase activity in a manner dependent on the presence of cytokinin. These results strongly suggested that AHK4 is involved in the cytokinin-signaling pathway, as a direct receptor molecule, in Arabidopsis.
Ueguchi
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Bioscience Center, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan. cueguchi@agr.nagoya-u.ac.jp
Sato
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Kato
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Tabata
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D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins; D002734:Chlorophyll / Q000378:metabolism; D002874:Chromosome Mapping; D003583:Cytokinins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005816:Genetic Complementation Test; D000071677:Histidine Kinase; D016296:Mutagenesis; D010641:Phenotype; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000254:growth & development; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D003583:Cytokinins; D002734:Chlorophyll; D011494:Protein Kinases; D000071677:Histidine Kinase; C000605492:AHK2 protein, Arabidopsis