Isolation, Characterization and Promoter Analysis of Cell Wall Invertase Gene SoCIN1 from Sugarcane (Saccharum spp.)

Cell wall invertase (CIN) plays an important role in carbohydrate partitioning and regulation of sink-source interaction. In this study, a full length cDNA encoding CIN gene was cloned by RT-PCR and RACE-PCR from sugarcane. The open reading frame of 1731 bp encodes a protein of 577 amino acids with a predicted molecular mass of 141.04 kDa and theoretical PI of 4.67. A size of 4,537 bp DNA encoding SoCIN1 was isolated, which contains seven exons and six introns. Using genome walking approach, a promoter sequence of 974 bp of SoCIN1 was isolated, and prediction with PlantCARE and PLACE software revealed that it has several key cis-regulatory elements known to be involved in various biotic and abiotic plant stresses. Relative expression in specific tissues was done using qRT-PCR, and the results demonstrated that SoCIN1 expression level was higher in the immature leaves and maturing leaves than the matured leaves and internodes at elongation stage and processing maturing stage. The conditions of 15 % PEG and 6 °C could have a similar function for inducing the expression of SoCIN gene in leaves, while 15 % PEG, 100 mM NaCl and 6 °C could induce the expression of SoCIN gene in roots.