Abstract: 【Objective】 To clone the small subunit encoding gene for adenosine diphosphate glucose pyrophosphorylase （AGPase） in Lilium brownii var. Viridulum （LbAGPS1）,and analyze its expression pattern,which could provide theoretical basis for promoting starch synthesis,accumulation and expansion of lily bulbs by regulating the expression of this gene.【Method】The gene LbAGPS1 was cloned from young leaves of tissue culture seedlings of L. brownii var. Viridulum by homologous cloning technique,and bioinformatic analysis and subcellular localization were performed.The expression difference of LbAGPS1 gene in leaf,scale and bulb base disc of L. brownii var. Viridulum was analyzed by fluorescence quantitative PCR. 【Result】 The results showed that the LbAGPS1 gene contained a complete open reading frame （ORF） of 1569 bp,encoding a hydrophilic protein consisting of 522 amino acids,the secondary structures consisted of α-helix（23.56%）,β-fold（20.12%）,random coil（50.38%） and β-turn（5.94%）.The LbAGPS1 protein had the characteristic structure of glucose-1-phosphate adenylate transferase and belonged to the cl33437 family protein.It had PLN02241,GlgC conserved domains,9 oligomer interface features and 10 ligand binding sites.The phylogenetic tree indicated that the LbAGPS1 protein was closely related to the small subunits of AGPase protein in Asian lily.Subcellular localization analysis showed that LbAGPS1 protein was located in chloroplasts of tobacco leaves.Real-time fluorescence quantitative PCR analysis showed that the LbAGPS1 gene was mainly expressed in the bulbs of L. brownii var. Viridulum,and the expression level was significantly higher than that in the leaves and bulb base discs.The relative expression level was the highest in the inner scales of the bulbs,followed by the middle and outer scales. 【Conclusion】 The protein encoded by LbAGPS1 gene contains the PLN02241 and GlgC conserved domains and characteristic sites of the cl33437 family.It is mainly expressed during the development of scales in bulbs and has obvious tissue expression specificity.