Overexpression of TaMADS1, a SEPALLATA-like gene in wheat, causes early flowering and the abnormal development of floral organs in Arabidopsis.

The MADS box genes are essential for floral development of Arabidopsis because they regulate flowering time and the development of floral organs. In this study, a MADS box gene, TaMADS1, was isolated and characterized from wheat (Triticum aestivum L.). The analysis of amino acid sequences and phylogenetic tree suggested that the TaMADS1 gene might be a SEPALLATA (SEP)-like gene. RNA hybridization indicated that the TaMADS1 transcripts began to accumulate in spikelets, and then, in floret primordia and floral organ primordia in wheat. In the later stage of floret development, the TaMADS1 transcripts accumulated in four whorls of young floral organs. The ectopic expression of TaMADS1 in Arabidopsis caused early flowering and altered the development of all floral organs. Further studies demonstrated that the early flowering phenotype in transgenic plants could be correlated with the upregulation of some flowering time genes and flower meristem identity genes. Our results suggest that TaMADS1 could be a putative SEP-like gene, and has diverse roles in flower development.