Putative Allele of D10 Gene Alters Rice Tiller Response to Nitrogen

The number of tillers in rice significantly affects final yield, making it a key trait for breeding and nitrogen-efficient cultivation. By investigating agronomic characteristics, we analyzed phenotypic differences between the wild-type P47-1 and the mutant <i>p47dt1</i>, performing genetic analysis and gene mapping through population construction and BSA sequencing. The <i>p47dt1</i> mutant, exhibiting dwarfism and multiple tillering, is controlled by a single gene, <i>P47DT1</i>, which is tightly linked to <i>D10</i>. A single base mutation (T to G) on chromosome 1 alters methionine to arginine, supporting <i>D10</i> as the candidate gene for <i>p47dt1</i>. To investigate nitrogen response in tillering, KY131 (nitrogen-inefficient) and KY131<i>^OsTCP19</i>^-H (nitrogen-efficient) materials differing in <i>TCP19</i> expression levels were analyzed. Promoter analysis of <i>D10</i> identified TCP19 as a nitrogen-responsive transcription factor, suggesting <i>D10</i>'s potential role in a TCP19-mediated nitrogen response pathway. Further analysis of P47-1, p47dt1, KY131, and KY131<i>^OsTCP19</i>^-H under different nitrogen concentrations revealed <i>p47dt1</i>'s distinct tiller response to nitrogen, altered nitrogen content in stems and leaves, and changes in <i>TCP19</i> expression. Additionally, <i>D10</i> and <i>TCP19</i> expression levels were lower in KY131<i>^OsTCP19</i>^-H than KY131 under identical conditions. In summary, <i>P47DT1</i>/<i>D10</i> appears to modulate nitrogen response and distribution in rice, affecting tiller response, possibly under TCP19's regulatory influence.