EST database for early flower development in California poppy (Eschscholzia californica Cham., Papaveraceae) tags over 6000 genes from a basal eudicot

The Floral Genome Project (FGP) selected California poppy (Eschscholzia californica Cham. ssp. Californica) to help identify new florally-expressed genes related to floral diversity in basal eudicots. A large, non-normalized cDNA library was constructed from premeiotic and meiotic floral buds and sequenced to generate a database of 9079 high quality Expressed Sequence Tags (ESTs). These sequences clustered into 5713 unigenes, including 1414 contigs and 4299 singletons. Homologs of genes regulating many aspects of flower development were identified, including those for organ identity and development, cell and tissue differentiation, cell cycle control, and secondary metabolism. Over 5% of the transcriptome consisted of homologs to known floral gene families. Most are the first representatives of their respective gene families in basal eudicots and their conservation suggests they are important for floral development and/or function. App. 10% of the transcripts encoded transcription factors and other regulatory genes, including nine genes from the seven major lineages of the important MADS-box family of developmental regulators. Homologs of alkaloid pathway genes were also recovered, providing opportunities to explore adaptive evolution in secondary products. Furthermore, comparison of the poppy ESTs with the Arabidopsis genome provided support for putative Arabidopsis genes that previously lacked annotation. Finally, over 1800 unique sequences had no observable homology in the public databases. The California poppy EST database and library will help bridge our understanding of flower initiation and development among higher eudicot and monocot model plants and provide new opportunities for comparative analysis of gene families across angiosperm species.