Daminozide enhances the vigor and steviol glycoside yield of stevia (Stevia rebaudiana Bert.) propagated in temporary immersion bioreactors

Abstract

Stevia (Stevia rebaudiana Bertoni) contains sweet compound widely used as natural sweetener, steviol glycoside (SG). SG is a diterpenoid secondary metabolite synthesized from ent-kaurenoic acid, the same precursor of Gibberellin (GA). Therefore, in this study, a GA inhibitor, Daminozide (0, 10, 20 ppm) was used to block ent-kaurenoic acid conversion towards GA synthesis in attempt to increase SG content of stevia propagated in Temporary Immersion Bioreactor (TIB). Daminozide in 10 mg/L was observed to be the optimum concentration which increased biomass weight and SG content (stevioside and rebaudioside A) up to 40%. The treatment also increased transcripts accumulation of genes enrolled in SG biosynthesis, such as SrKA13H, SrUGT85C2, and SrUGT76G1, indicating SG pathway become more active due to the inhibition of GA pathway. Furthermore, the inhibition of GA was also indicated by the upregulated expression of GA biosynthesis gene (GA3ox) as the result of feedback regulation, and the downregulated expression of GA catabolism gene (GA2ox2) as the result of feed-forward regulation caused by inhibitor treatment. Key MessageThis study reports data regarding the in uence of inhibition to the late-stage of GA biosynthesis by chemical treatment in modulating SG yield from stevia in vitro culture; SG and GA pathways are related.

Modern Approaches to In Vitro Clonal Banana Production: Next-Generation Tissue Culture Systems

“…increased from 2 to 10 times compared to solid culture using the Bioreactor system. Saptari et al [31] obtained up to a 40% increase in rates of viability and steviol glycoside yield in the bioreactor system in the stevia plant. In this study, using bioreactors, the wet weight data increased by 23% in the 'Grande Naine' variety and 61% in the 'Azman' variety compared to the solid culture method.…”

Critical Review on Key Approaches to Enhance Synthesis and Production of Steviol Glycosides: A Blueprint for Zero-Calorie Sweetener

“…Moreover, the mass production of adventitious root for SvGls synthesis under the influence of nutrient supplements [53] and application of melatonin (MEL) [61] as a plant growth supplement and stress inducer (under saline conditions) are unique and very advantageous approaches for bulk production of SvGls. Additionally, the reverse strategy to inhibit the GA synthesis [62] may be a promising approach to enhance SvGls levels. However, further work in this area will establish the optimum growth condition for growing the stevia plants under several stress conditions.…”