Microrhizome induction and curcumin accumulation in Curcuma aromatica Salisb.

Abstract

White turmeric (Curcuma aromatica Salisb.) contains notable secondary metabolites with significant health benefits. However, the efficiency of traditional cultivation of white turmeric is limited by many environmental factors. Therefore, it is of great significance to study the large-scale production of superior-quality microrhizomes for cultivation and secondary metabolite extraction, without relying on natural rhizomes. In this study, the effects of sucrose, plant growth regulators (6-benzyl amino purine - BAP, kinetin - KIN, α-naphthaleneacetic acid - NAA, indole-3-butyric acid - IBA), boric acid (H3BO3), salicylic acid (SA), and yeast extract (YE) on white turmeric microrhizomes induction and growth were examined. The stimulating effects of SA and YE on curcumin accumulation in microrhizomes were also investigated. Microrhizomes were divided into groups of varying diameters (5–10, 10–15, 15–20, and?> 20 mm) and then grown under ex vitro conditions to examine the effect of microrhizome size on germination rate. Our findings suggest that YE is an excellent stimulator of microrhizome growth and may contribute to the replacement of rhizomes with in vitro microrhizomes to produce secondary metabolites. Specifically, microrhizomes induced in medium with 0.5 mg/L YE accumulated 25 times the amount of curcumin that was produced by native rhizomes. Moreover, the optimal medium for microrhizome growth also contained YE (MS medium with 8 g/L agar, 80 g/L sucrose, 11 μM AgNO3, and 0.5 mg/L YE). In addition to the beneficial effects of YE, the stimulating impacts of SA and H3BO3 on the induction and growth of white turmeric microrhizomes were also discovered for the first time. Among all the plant growth regulators tested, NAA primarily stimulated callus formation but had no significant effect on microrhizome growth. Microrhizomes (diameter?> 20 mm) were successfully acclimatized, and the germination rate, germination time, and shoot height were 83.33%, 5.21 weeks, and 45.10 mm, respectively.