Thellungiella halophila (T. Halophila) (salt cress) is a close relative of Arabidopsis and a model plant for salt tolerance research. However, the nature of its later flowering causes some difficulties in genetic analysis. The FRIGIDA (FRI) gene plays a key role in the Arabidopsis vealization flowering pathway, whose homolog in T.halophila may also be a key factor in cotrolling flowering time.In order to study the molecular mechanism of vealization responses in T.halophila,a full length cDNA named ThFRI(Thellungiella halophila FRIGIDA)was isolated from the young seedlings of T.halophila by RT-PCR and RACE.The ThTRI cDNA was 2017 bp in length and contained an open reading frame encoding a putative protein of 605 amino acids. The ThFRI showed significant homology to AtFRI(74.5%at the nucleotide level and 63.9% at the amino acid level).To study its function,ThFRI cDNA was transformed into Arabidopsis thaliana,driven by CaMV 35S promoter. Transgenic plants expressing ThFRI is the funtional FRI homolog in T.halophila.The cloning and funtional charac-terization of the FRI homolog of T.halophila will faciliate further study of flowering time control in T.halophila.