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