ARABIDOPSIS-THALIANA ECP-63 ENCODING A LEA PROTEIN IS LOCATED IN CHROMOSOME-4

DCECP63 is a carrot embryogenic cell protein. To perform its genetic a nalysis, we isolated an Arabidopsis thaliana (At) ECP63 cDNA. The cDNA encoded a polypeptide oi 449 amino acids (aa). Its deduced aa sequenc e showed extensive similarity with DCECP63, DCDC8 and BPBP8 which are embryonic proteins isolated from carrot and birch, respectively. The a a sequence contained eight well-conserved tyrosine phosphorylation sit es and 16 repeals of 11 aa. Southern analysis showed that the AtECP63 gene might belong to a small multigene family. The AtECP63 transcripts accumulated specifically in mature seeds, and exogenous abscisic acid (ABA) induced its expression in immature siliques, but not in vegetat ive tissues. These results suggested that the AtECP63 gene encoding a putative phosphotyrosine protein belonging to late embryogenesis abund ant (LEA) protein in group 3 might be involved in maturation and desic cation tolerance of seeds. Restriction fragment length polymorphism (R FLP) and cleaved amplified polymorphic sequence (CAPS) mapping showed that AtECP63 gene was present in the South part of chromosome 4.