[Identification of SbNF-YA3 and analysis of its association with grain traits in sorghum]

Sorghum is an important grain crop in arid and saline-alkali areas. Grain size is an important factor limiting the yields of cereal crops. However, the genes regulating the development of grain size in sorghum remain unclear. In this study, the NF-YA transcription factors of sorghum were analyzed. The results revealed that SbNF-YAs exhibited tissue expression specificity, among which SbNF-YA3 was specifically highly expressed during the grain development stage of sorghum. The coding region of SbNF-YA3 contained 747 bases and encoded 248 amino acid residues. This gene had a CBFB-NFYA domain and belonged to the NF-YA gene family. Its promoter region was composed of multiple cis-elements. Drought, salt, high temperature, low temperature, and ABA treatment caused the down-regulated expression of SbNF-YA3. The natural variation analysis of SbNF-YA3 revealed that Hap1 was the main haplotype. SbNF-YA3 (SNP37) was highly significantly correlated with grain length, grain width, and 1 000-grain weight in the three environments of "2022 Dongbai" "2023 Yuncheng" and "2023 Dongbai". SNP37-A was an excellent allelic variation and it was artificially selected during the evolution process. This study reveals the molecular basis by which SbNF-YA3 regulates the grain size of sorghum, providing strong evidence for the development of molecular markers in sorghum breeding, the detection of excellent alleles regulating grain size, and the creation of new high-quality sorghum varieties.