In silico identification of cis-regulatory elements of phosphate transporter genes in rice (Oryza sativa L.)

Promoter sequences of 13 Phosphate Transporter genes of Oryza sativa L. (OsPTs) have been analyzed in silico to identify their cis-regulatory elements (CREs). The DNA sequences of these OsPT genes were mined from NCBI gene databases. MEGABLAST program was used to align these sequences to Rice Genome Database in obtaining their complete sequences. The upstream region (−1 to −400) of the complete gene sequences were analyzed using SIGNALSCAN program provided by PLACE database of cis-regulatory element motives. From this procedure, 153 types of CRE were identified. Four of these CREs were found on all of the OsPT genes: ARR1AT, CAATBOX1, CACTFTPPCA1, and DOFCOREZM. Among these CREs, CACTFTPPCA1 was found with 3 to 15 duplications in each cis-regulatory sequence. In addition, each OsPT gene has typical CREs that can only be found in the respective genes. The total number of these typical CREs is 54, and one of them was a binding site for a bHLH-like protein, CACGTGMOTIF or the G-box. Moreover, several E-boxes which also functioned as a binding site for a bHLH-like protein were identified in all OsPTs except in OsPT1, OsPT6, and OsPT8. There were significant correlations (p < 0.05) between mRNA levels of OsPT1 to OsPT11 in rice root with or without inoculation of Glomus intradices reported by Paszkowskidagger et al. (2002) and the duplication numbers of ARR1AT, CAATBOX1, CACTFTPPCA1, CURECORECR, and WRKY71OS.