Genome-Wide Identification of the RR Gene Family and Its Expression Analysis in Response to TDZ Induction in .

The cytokinin response regulator (RR) gene is essential for cytokinin signal transduction, which plays a crucial role in plant growth and development. Here, we applied bioinformatics to 's genome to identify its RR gene family and systematically analyzed their gene characteristics, phylogenetic evolution, chromosomal localization, collinearity analysis, promoter cis-elements, and expression patterns. Overall, 33 genes were distinguished and classified into three types. All these genes harbored motif 5 (YEVTTVNSGLEALELLRENKB), the most conserved one, along with the plant-conserved domain (REC domain), and could be mapped to 10 chromosomes with four gene pairs of segmental replication events but no tandem replication events; 13 genes showed collinearity with genes. Promoter analysis revealed multiple hormone-related -elements in the RR genes. After a TDZ (thidiazuron) treatment, 13 genes had higher expression levels than the control, whose magnitude of change depended on the developmental stage of leaves' adventitious buds. The expression levels of , , , and agreed with the average number of adventitious buds post-TDZ treatment. We speculate that these four genes could figure prominently in bud regeneration from leaves in vitro. This study provides detailed knowledge of for research on cytokinin signaling and functioning in .