Fagopyrum esculentum(buckwheat,Polygonaceae) is a multi-food-use pseudocereal with healing benefits and is growing on arid areas.(1)Based on homology and RACE method,a RD21 orthologous gene from buckwheat was isolated and identified.The RD21 homologous gene from F.esculentum transcript was 1 750 bp and contained a 1 407 bp ORF(Open Reading Frame,ORF) encoding 468 amino acids.(2)Protein sequence alignment and phylogenetic analyses grouped FeRD21 into PLCPs subfamily members which carry a C-terminal granulin domain.(3)The protease of FeRD21 was highly conserved and harbored the conservation sites of catalytic residues Cys¹⁶⁸-His³⁰⁴-Asn³²⁴.(4)Expression analysis suggested that FeRD21 was up-regulated by salt,dehydration,ABA,and senescent treatments,which showed a different way in response to stresses with RD21 in Arabidopsis.Our results indicated that FeRD21 might be involved the stress-responsive pathways in F.esculentum.