Analysis of expressed sequence tags of flower buds in Lotus japonicus

In order to study gene expression in a reproductive organ, we constructed a cDNA library of mature flower buds in Lotus japonicus, and characterized e xpressed sequence tags (ESTs) of 842 clones randomly selected. The EST sequ ences were clustered into 718 non-redundant groups. From BLAST and FASTA se arch analyses of both protein and DNA databases, 58.5% of the EST groups sh owed significant sequence similarities to known genes. Several genes encodi ng these EST clones were identified as pollen-specific genes, such as pecti n methylesterase, ascorbate oxidase, and polygalacturonase, and as homologo us genes involved in pollen-pistil interaction. Comparison of these EST seq uences with those derived from the whole plant of L, japonicus, revealed th at 64.8% of EST sequences from the flower buds were not found in EST sequen ces of the whole plant. Taken together, the EST data from flower buds gener ated in this study is useful in dissecting gene expression in floral organ of L. japonicus.