Flowering time gene'CONSTANS''homologs in wheat: isolation and functional analysis in trasgenic rice.

摘要

The control of flowering by photoperiod is an important adaptive characteristic in plants. The CONSTANS gene of Arabidopsis, a long-day plant, has an important role in the regulation of flowering by photoperiod. Recently, a major QTL controlling heading date in response to photoperiod, Hdl gene, was isolated from rice, a short-day plant. Hdl gene was an ortholog of CONSTANS. In this study, we isolated three kinds of Hdl homolog from wheat, a facultative long-day plant. They harbored two conserved regions: two zinc finger B-boxes and CCT domain like HdllCO. They were homoeologous genes located on the long arm of homoeologous chromosome group 6 of hexaploid wheat, and were named TaHdl. For functional analysis, one of the TaHdl genomic clone was introduced to a rice mL[Hdl/Hd2], which shows no photoperiod response. The transgenic rice plants with the TaHdl-1 gene were promoted for heading under the short-day condition and delayed under the long-day condition. The results confirmed that the product ofthe TaHdl-1 gene fulfills the same function as that of Hdl in rice.