Large-scale analysis of expressed genes from the leaf of oilseed rape (Brassica napus L.)

While the number of leaf-specific expressed genes is estimated to be approximately 6,000, an overview of gene diversity and expression patterns in the leaf of oilseed rape (Brassica napus L.) has not yet been reported. In an effort to understand gene expression patterns and to identify new genes, we generated 754 expressed sequence tags (ESTs) from the leaf of B. napus. By comparing them to public databases, we showed that 204 of the ESTs (27.1%) have sequence homology to known genes, with 52 of them (6.9%) matching to genes not previously studied in B. napus. The most abundant transcripts were found to be involved in photosynthesis and energy metabolism. When compared with maize leaf ESTs and rice leaf ESTs, the pattern of gene expression was different depending on the developmental stages of the leaf.