Aspartic proteases gene family in rice: Gene structure and expression, predicted protein features and phylogenetic relation

Abstract

Aspartic proteases constitute a large family in eukaryotes, which play fundamental roles in protein processing, maturation and degradation. In this study, we identified 96 OsAP genes in rice ( Oryza sativa L.), the model plant for monocots, by a reiterative database search. The analysis of the complete set of OsAP genes is presented, including chromosomal location, phylogenetic relationships, classification and gene structure. Moreover, a comprehensive expression analysis of OsAP family genes was performed using 24 tissues during the plant life cycle of two rice cultivars. Sixty-six OsAP genes were found to be expressed in at least one of the examined developmental stages, which were divided into 3 classes based on their transcript levels. OsAP genes were also found to be differentially up- or down-regulated in rice seedlings in response to treatments with phytohormones, as well as in plumules/radicles under light/dark conditions. The comprehensive annotation and expression profiling undertaken in this research add to our understanding of OsAP family genes in rice growth and development. Our results also provide a basis for selection of candidate genes for functional validation in future studies.