Abstract:To explore the relationship between lipid biosynthesis and relevant gene expression in sea buckthorn seeds, we harvested the developing seeds of the line ‘Xin’e 3’ with high oil content and the line ‘Suiji 1’ with low oil content as experimental materials on June 25, July 6, 17, 28, August 8 and 19. These two lines had closed genetic relationship. The oil content in seeds was determined by the method of chloroform methanol, and the expression profiles of GPD1, DGAT1 and DGAT2 genes involved in lipid biosynthesis were tested using real time quantitative PCR. The results showed that: (1) the oil content in the seeds of ‘Xin’e 3’ was higher than that in ‘Suiji 1’ except for July 17. The rapid accumulations of seed lipid of these two lines were during July 6 to 28, and the increasing rates in ‘Xin’e 3’ were higher than that in ‘Suiji 1’; (2) the high expression of GPD1 gene occurred in the period of rapid lipid accumulation, which may speed up lipid biosynthesis in ‘Xin’e 3’ seeds through promoting the biosynthesis of glycerol 3 phosphate. The expression levels of DGAT1 and DGAT2 genes in line ‘Xin’e 3’ were higher than that in line ‘Suiji 1’ during lipid accumulation. Thus, GPD1, DGAT1 and DGAT2 genes may be associated with the high accumulation of lipid in ‘Xin’e 3’ seeds. These results provided scientific bases for validating the function of genes encoding for rate limiting enzymes involved in sea buckthorn lipid biosynthesis and accumulation.