In the present study, different elicitors, viz., polyethylene glycol (PEG), alginate (ALG), chitosan (CHI), salicylic acid (SA), and yeast extract (YE), were used in in vitro shoot cultures of Stevia rebaudiana for 4 wk to decipher their effect on growth, biomass yield, and accumulation of steviol glycosides (SG), especially rebaudiosides. The highest leaf number (16.33), root number (4.67), and shoot length (3.80 cm) were observed in media supplemented with 0.5 mg/L YE, whereas maximum shoot number (2.44) and root length (1.89 cm) were recorded in 1.5 mg/L CHI and 1.0 mg/L PEG respectively. Elicitation by 1.0 mg/L YE resulted in enhanced biomass production with a maximum fresh weight of leaves (114.01 mg/plantlet), stem (90.27 mg/plantlet), and shoots (204.28 mg/plantlet). SG content was quantified through ultra-high-performance liquid chromatography (UHPLC). Stevioside (ST) content was increased by 5-fold (0.77 mg/g leaf DW) in 2.0 mg/L ALG and rebaudioside A (RA) by 7-fold (1.9 mg/g leaf DW) in 0.5 mg/L ALG. Enhancement of SG is mainly regulated by a key gene, UGT85C2, which was further validated through qRT-PCR and in silico promoter analysis. Also, cis-regulatory elements governing transcriptional regulation linked with the biosynthesis of SG were identified in key genes. The study unveils ALG as a promising elicitor to produce quality biomass with enhanced metabolite profile in S. rebaudiana.

在本研究中，不同的引发剂，例如聚乙二醇（PEG），藻酸盐（ALG），壳聚糖（CHI），水杨酸（SA）和酵母提取物（YE），被用于甜叶菊的体外芽培养。连续4周分析其对甜菊糖苷（SG）尤其是莱鲍迪苷的生长，生物量产量和积累的影响。在添加0.5 mg / L YE的培养基中，观察到最高的叶数（16.33），根数（4.67）和枝长（3.80 cm），而记录的最大枝数（2.44）和根长（1.89 cm） 1.5 mg / L CHI和1.0 mg / L PEG。以1.0 mg / L的YE进行诱导会提高生物量的产量，最大的鲜重是叶片（114.01 mg /株），茎（90.27 mg /株）和枝条（204.28 mg /株）。SG含量通过超高效液相色谱（UHPLC）进行定量。在2.0 mg / L ALG中，甜菊糖苷（ST）含量增加了5倍（0.77 mg / g叶DW），在0.5 mg / L ALG中，莱鲍迪苷A（RA）的含量增加了7倍（1.9 mg / g叶DW）。UGT85C2，已通过qRT-PCR和计算机启动子分析进一步验证。同样，在关键基因中鉴定出了与SG的生物合成有关的，控制转录调控的顺式调控元件。这项研究揭示了ALG是一种很有希望的诱因，它可以在瑞氏链球菌中生产具有增强的代谢产物的高质量生物质。