βcarotene isomerase (D27) is the first enzyme involved in strigolactones biosynthesis. In this study, the cDNAs encoding βcarotene isomerase (TaD27) were cloned from wheat cultivar Chinese Spring by RTPCR. Further, their expression in different tissues and under low phosphate stress were analysed by Realtime Quantitative PCR. The result showed that: (1) Two TaD27 cDNAs were cloned, which was maped on the long arms of 7A and 7D chromosome, respectively (named TaD277AL and TaD277DL). In addition, we found another locus located on chromosome 7BL encoding the third homolog (TaD277BL) by sequence analysis. (2) Each of the three TaD27s contains 7 exons composing an ORF of 828 bp (7AL), 840 bp(7BL) or 843 bp (7DL), respectively and encodes a protein containing a chloroplast transit peptide at Nterminal. Phylogenetic analyses indicated that D27s in plants clustered into three independent clades. TaD27s share a high level of identity with orthologs in other monocots such as Oryza sativa and Zea mays, as a result, they are clustered in the same clade. (3) The expression level of TaD27 is relatively high in leaves, sheaths and stems, lower in young panicles, and lowest in roots. Under low phosphate stress the expression of TaD27 in roots is down regulated to the bottom in 6-12 h firstly, and then it rises to the normal level after 96 h. On the contrary, the expression of TaD27 in leaves is up regulated in early stage and the peak is at 6h, then it continuously drops to a relatively low point at 96 h.