Papain-like and legumain-like proteases in rice: genome-wide identification, comprehensive gene feature characterization and expression analysis.

Background: Papain-like and legumain-like proteases are proteolytic enzymes which play key roles in plant development, senescence and defense. The activities of proteases in both families could be inhibited by a group of small proteins called cystatin. Cystatin family genes have been well characterized both in tobacco and rice, suggesting their potential roles in seed development.

Genome-wide identification and characterization of cystatin family genes in rice (Oryza sativa L.).

11 Cystatin genes in rice were identified, and their expression patterns were comprehensively analyzed, which reveals multiple roles in both seed development and plant response to environmental variations. Cystatin is a group of small proteins and known to inhibit the activities of cysteine proteases in the papain C1A and legumain C13 peptidase families in plants. Cystatin family genes have only been well characterized recently in a few plant species such as Hordeum vulgare and Nicotiana tabacum, which show their critical roles in programmed cell death and responses to biotic stresses.