水稻抽穗期基因OsFD1的遗传多样性及单倍型分析

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Abstract：Rice （Oryza sativa L.），a globaly-important staple food crop，exhibits heading date characteristics that directly determine its regional adaptabilityand yield potential. While OsFD1 isrecognized as a keyregulatorof rice heading date，its genetic diversity and functional variations remain insufficiently investigated.This study performed resequencing analysis of the OsFD1 gene in 192 Asian cultivated rice accessions and 58 wild rice samples，integrating the heading date records to elucidate the gene's functional significance. Our analysis identified 1 InDel and 18 SNPs across the coding and promoter regions of OsFDI ， defining 7 exon haplotypes （Chap，coding region haplotype）and 6 promoter haplotypes （Phap，promoter region haplotype）.Functional assessment revealed that five coding region variants（21292259 bp，CCT deletion; 21292352 bp， C⟶A ；21292370 bp， ΔTC ； 21292477 bp， GA ；21292634 bp， ΔTC ）significantlyassociated with heading date in cultivated rice.Notably，the CCT deletion （21292259 bp） disrupts hydrogen bond during the formation of FACHd3a . Promoter analysis uncovered a T⟶A variation at 21289993 bp in Aus varieties，which eliminates a GATA-motif regulatory element，while japonica rice retained the intact GATA-motif， potentially explaining observed subspecies-specific heading date differences.No unique variations were found in the coding region of OsFDl in wild rice，suggesting that functional OsFDl polymorphisms arose and became gradually fixed during domestication and subsequent breeding.Additionall，new variations in cultivated rice contributed to heading date diversity. These findings demonstrate that natural variations and haplotype diversity of OsFD1 underpin rice's photoperiod adaptation and climatic resilience，reflecting adaptive evolution.The identified variants offer potential targets for molecular breeding.Further studies onthe function and regulatory mechanisms of OsFD1 will facilitate precise regulation of heading date and advance rice variety improvement.

Key words： rice;heading date; OsFDI ; haplotype

水稻（OryzasativaL.）是最重要的谷物之一，为全球超过一半的人口提供主食。（剩余19050字）