水稻突变基因DHD9调控抽穗期的信号途径分析OA

[Objective]Heading date,a crucial agronomic trait that determines rice yield and adaptability,is governed by a complex regulatory network.The identification of genes governing heading date is therefore crucial for elucidating the molecular mechanisms underlying the regulation of heading date in rice.[Method]A delayed heading date mutant(dhd9)and its wild type(WT)was used as experimental material to investigate the biological function of the DHD9 gene in the regulation of heading date by integrating analyses of phenotypic traits,expression patterns of key heading date regulatory genes,and the molecular association between DHD9 and the circadian clock system.[Result]Under natural long-day conditions,heading date of dhd9 was delayed by approximately 9 days compared to the WT,while under artificial short-day conditions,the delay extended to about 26 days.Plant height,panicle length,number of primary and secondary branches,grains per panicle,seed setting rate,and yield per plant were all significantly increased in dhd9 compared to WT,except for a significant reduction in effective panicle number.Under both natural long-day and short-day conditions,expression levels of florigen genes Hd3a and RFT1,their downstream gene OsMADS14,and the upstream regulator Ehd1 were significantly downregulated in dhd9 relative to WT,indicating that DHD9 may regulate heading date through the Ehd1-Hd3a/RFT1 flowering pathway.Additionally,significant alterations in expression were observed in core circadian clock genes OsPRR37,OsPRR59,and OsPRR73 in dhd9.[Conclusion]DHD9 is a regulatory factor controlling heading date and yield in rice.It regulates heading date through the Ehd1-RFT1/Hd3a signaling pathway,as well as by influencing the circadian clock system.These findings lay a foundation for elucidating the molecular mechanism by which DHD9 regulates heading date in rice.