Spectral regulation of growth, secondary metabolism, and iridoid pathway gene expression in in vitro cultures of Valeriana jatamansi
摘要
Precise control of LED light quality and condition serves as an effective tool to facilitate plant growth, enhance photosynthetic efficiency, and increase phytochemical production in controlled in vitro environments. Therefore, in this study, the effect of different LED lights (red, blue, warm white (yellow hue), and cool white, serving as a control) on the growth, physiological responses, biochemical parameters, secondary metabolite accumulation, and gene expression pattern of in vitro raised Valeriana jatamansi was systematically examined. MS medium supplemented with 1 mg L−1 BAP exhibited the best response for both shoot and root induction. Maximum shoot height (9.71 cm) was observed under blue light, while the highest leaf number (20.22) and root number (15.11) were found under white light. Red light promoted the maximum fresh and dry weight in both leaf and root tissues. Chlorophyll fluorescence measurements showed stable photosynthetic efficiency across all light treatments. However, catalase activity in root and leaf tissues were found highest under white light condition. The accumulation of valtrate was found maximum under white and yellow light in leaf (0.090 mg/g DW) and root tissue (0.167 mg/g DW), respectively. Additionally, qRT-PCR analysis demonstrated a significant upregulation of iridoid biosynthetic pathway genes (GES, G10H, and 7DLS) under both yellow and white light conditions. These findings demonstrated that tailored LED treatment can differentially regulate growth-metabolite-gene expression relationships in V. jatamansi. Notably, this study provides the first integrated report linking LED light quality with iridoid pathway gene regulation and valtrate biosynthesis in this species, highlighting its potential for sustainable in vitro production and conservation-oriented pharmaceutical applications.