Inulin content and expression of related genes in different tissues and cell suspension culture of Taraxacum kok-saghyz

The roots of Taraxacum kok-saghyz L.E. Rodin are rich in the storage carbohydrate inulin, which is known as a probiotic compound in human health. In this study, the relative expression of the inulin biosynthesis pathway genes (1-SST, 1-FFT, and 1-FEHI) was investigated in the roots, leaves, and cell suspension cultures. Also, the effect of 1-naphthaleneacetic acid (NAA) and methyl-jasmonate (MeJA) and the combination of both (MeJA/NAA) on T. kok-saghyz cell suspension culture is studied for the first time. The results showed a higher relative expression of the inulin biosynthesis genes in roots compared to leaves at both rosette and flowering stages. In addition, the relative expression of 1-SST and 1-FFT genes in the cell suspension was significantly reduced, while the 1-FEHI gene was upregulated compared to the roots. Regarding the results, low concentrations of NAA and MeJA were factors that strongly affected the expression of the 1-FFT gene, while the 1-SST gene showed high expression in low concentration NAA and its combination with MeJA. However, the relative expression of the 1-FEHI gene was significantly reduced in all treatments compared to the control. HPLC analysis results showed that the suspension culture treated with a low concentration of NAA had a higher amount of inulin than the control culture, which could be resulted due to the increased expression of 1-SST and 1-FFT genes. Results show that the low concentration NAA elicitation is a useful method for the enhancement of inulin production in cell suspension culture of T. kok-saghyz.