Isolation and structural analysis of a gene coding for a novel type of aspartic proteinase from buckwheat seed (Fagopyrum esculentum Moench)

A novel type of aspartic proteinase gene was isolated from the cDNA library of developing buckwheat seeds. This cDNA, FeAPL1, encoded an AP-like protein lacking the plant-specific insert (PSI) domain characteristic of typical plant aspartic proteinases. In addition the corresponding genomic fragment was isolated. It is demonstrated that this gene does not contain introns. Since bioinformatics analysis of the Arabidopsis genome showed that most potential AP genes are intronless and PSI-less, it appears that "atypical" is an inappropriate word for that class of AP. Isolation of this specific buckwheat gene among the small group of those isolated from other plant species provides a new perspective on the diversity of AP family members in plants.