Cytokinin treatment on aerial parts of seedlings

In Arabidopsis thaliana, the immediate early response of plants to cytokinin is formulated as the multistep AHK-AHP-ARR phosphorelay signaling circuitry, which is initiated by the cytokinin-receptor histidine protein kinases. In the hope of finding components (or genes) that function downstream of the cytokinin-mediated His-Asp phosphorelay signaling circuitry, we carried out genome-wide microarray analyses. To this end, we focused on a pair of highly homologous ARR10 and ARR12 genes by constructing an arr10 arr12 double null mutant. The mutant alleles used in this study were arr10-5 and arr12-1. arr10-5 is the SALK_098604 T-DNA insertion line, whose mutation was determined to be located in the fifth exon of the ARR10 coding sequence. Arr12-1 is the SALK_054752 T-DNA insertion line, whose mutation was determined to be located in the third exon of the ARR12 coding sequence. The resulting mutant exhibits a characteristic phenotype with regard to the cytokinin-mediated His-Asp phosphorelay. Here we, therefore, compared response to cytokinin in wild type with that in arr10 arr12 double mutant. In this study, wild type and the arr10 arr12 double mutant grown vertically on MS agar plates for 2 weeks were treated with 20uM t-zeatin or 0.02% DMSO (solvent for t-zetion solution) for 1h. These treated plant samples were divided into three portions, from which RNA samples were prepared separately from aerial parts of seedlings with use of RNeasy Plant Mini Kit (Qiagen, Valencia, CA, U.S.A.). The Quality of RNAs prepared was analyzed by Bioanalyzer 2100 (Agilent Technologies). These RNA samples were processed as recommended by the Affymetrix instruction (Affymetrix GeneChip Expression Analysis Technical Manual, Affymetrix). These dataset will provide us with bases for understanding the early response to cytokinin on aerial parts of seedlings in Arabidopsis thaliana.

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Yokoyama A, Yamashino T, Amano Y, Tajima Y, Imamura A, Sakakibara H, Mizuno T