Genome-wide transcriptional profiling in relation to seed storage compounds in tetralocular Brassica rapa

Purpose: To elucidate the physiological and molecular mechanisms underlying seed development, we conducted a genome-wide transcriptional profiling of developing seeds of ‘Sarsyun’ at four different time points (21, 28, 35, and 42 DAF). 34,423 contigs from four different developing seeds (21, 28, 35, and 42 DAF) were analyzed for transcript abundance and changes to the timing of transcript abundance in relation to the accumulation of seed storage products. Most genes involved in seed photosynthesis and carbohydrate metabolism were highly expressed at 21 or 28 DAF and were subsequently downregulated. Expression of genes coding for oleosins and fatty acid synthesis and elongation markedly increased at 28 DAF through 35 DAF, respectively, remaining high thereafter. Expression of major storage protein genes increased at 28 or 35 DAF. Overall, our results showed that dynamic changes to transcript abundance of most genes in relation to seed storage products occurred between 28 and 35 DAF. Overall design: Two independent gene expression analyses (2 replications, total 8 samples, 3 comparisons; 28 DAF vs. 21 DAF , 35 DAF vs. 21 DAF , 42 DAF vs. 21 DAF)

8