Two Arabidopsis microarrays were used to analyze the differential expression of genes during seed development of a high-oil content Brassica napus cultivar, H105, planted in Nanjing (altitude: 8.9 m) and Lhasa (altitude: 3 658 m). The oil contents of H105 were (46.04±1.42)% in Nanjing and (53.09±1.35)% in Lhasa. We isolated the seeds 30 days after flowering at periods
preceding and including the major accumulation of storage oil. Transcript levels of 421 genes were altered two-fold or higher for H105 planted in Lhasa than in Nanjing. Of these, 192 showed up-regulated expression and 229 down-regulated expression. These differentially expressed genes were involved in different processes and had different functions, including metabolism, transportation, binding, transcription, structure, development, and signal transduction. Some key genes with differential expression, such as chlorophyll a-b binding protein, sucrose synthase, pyruvate kinase, 6-phosphogluconate dehydrogenase, ATP-citrate lyase, citrate synthase, isocitrate dehydrogenase, FAD6 and FAD7, relate to photosynthesis, sugar metabolism and fatty acid synthesis. These results reveal the expression profile of correlated genes in B. napus planted in two areas, and combined with results from others, suggest that the improvement of photosynthesis and sugar metabolism perhaps can increase lipid biosynthesis.