Effect of molybdenum on secondary metabolic process of glycyrrhizic acid in Glycyrrhiza uralensis Fisch.

Abstract A pot experiment was conducted to investigate into effects of molybdenum (Mo) on the secondary metabolic process of glycyrrhizic acid (GA). One-year-old seedlings were grown in pots with washed vermiculite and sand. Hoagland nutrition solution was irrigated with four concentrations: 0, 0.52, 5.2 and 10.4 mg L −1 . The accumulations of GA and its biosynthetic precursors ( β -amyrin and squalene) and then expression of the key synthase ( β -amyrin synthase, β -AS) were studied on 35, 70 and 105 d. In the early stage, that was on the 35 and 70 d, the contents of squalene and GA, and the expression of β - AS gene under 0.52 and 5.2 mg L −1 Mo treatments were significantly higher than that under 0 and 10.4 mg L −1 Mo. There was a contrary result of β -amyrin. However, the content of squalene under 0 mg L −1 Mo was the highest on 105 d. Thus, it suggested an appropriate concentration of Mo could promote the accumulation of GA, by affecting the biosynthetic process of GA at a certain time. Practically, the time and amount of application of Mo on Glycyrrhiza uralensis should be the noted.