Expression analysis of D-type cyclin in potato (Solanum tuberosum L.) under different culture conditions

Key message Taken together, this study suggests that potato D-type cyclin genes are expressed differentially between in vitro and planta caused by intrinsic differences in physiology and gene action at the cellular and whole organism levels. Abstract Cyclin performs a pivotal role in control of the cell cycle by forming a complex with cyclin-dependent kinases (CDKs). In this study, the potato cyclin D3 genes (StCycD3.1, StCycD3.2, and StCycD3.3) were isolated and analyzed. A sequence analysis showed that the potato cyclin D3 genes shared high levels of sequence homology with tomato cyclin D3 genes. The potato cyclin D3 genes revealed organ-specific expression; StCycD3.1 was strongly expressed in above-ground organs, whereas StCycD3.2 was strongly expressed in underground organs. The expression patterns of the potato cyclin D3 genes were analyzed under a variety of environmental conditions such as different carbon sources and hormones. Glucose (as a carbon source) and zeatin (as a hormone) were effective single factors for increasing potato cyclin D3 expression. Sucrose and zeatin were the most effective combination for high-level induction of the genes. Time-course-based gene expression patterns were evaluated in treatments of leaf explants with combinations of different light conditions and hormones. The potato cyclin D3 genes were expressed abundantly in the presence of hormones during the late stage of long-term dark conditions. The gene expression patterns were also monitored in entire potato plants under different light conditions. The gene expression levels were consistently low under the different light regimes but potato cyclin D3 genes were up-regulated during a shift in illumination from dark to light.