Physiological and Proteomic Insights Into Red and Blue Light-Mediated Enhancement of in vitro Growth in Scrophularia kakudensis—A Potential Medicinal Plant

Abstract

The current study has determined the effect of red and blue lights on the enhancement of growth, antioxidant property, phytochemical contents, and expression of proteins in Scrophularia kakudensis. In vitro-grown shoot tip explants of S. kakudensis were cultured on the plant growth regulator-free Murashige and Skoog (MS) medium and cultured under the conventional cool white fluorescent lamp (control), blue light-emitting diodes (LED) light, or red LED light. After 4 weeks, growth, stomatal ultrastructure, total phenols and flavonoids, activities of antioxidant enzymes, and protein expressions were determined. Interestingly, blue or red LED treatment increased the shoot length, shoot diameter, root length, and biomass on comparison with the control. In addition, the LED treatments enhanced the contents of phytochemicals in the extracts. The red LED treatment significantly elicited the accumulation of flavonoids in comparison with the control. In accordance with the secondary metabolites, the LED treatments modulated the activities of antioxidant enzymes. Moreover, the proteomic insights using two-dimensional gel electrophoresis system revealed the proteins involved in transcription and translation, carbohydrate mechanism, post-translational modification, and stress responses. Taken together, the incorporation of blue or red LED during in vitro propagation of S. kakudensis can be a beneficial way to increase the plant quality and medicinal values of S. kakudensis.

Combinations of Blue and Red LEDs Increase the Morphophysiological Performance and Furanocoumarin Production of Brosimum gaudichaudii Trécul in vitro

“…In fact, stem elongation is usually associated with blue light (Kong et al, 2018 , 2019 ), while red light has been identified as responsible for inducing decreases in the concentration of indo-3-acetic acid (IAA; Liu et al, 2014 ). Even so, red light can also induce stem elongation (Claypool and Lieth, 2020 ; Manivannan et al, 2021 ), and it is important to consider that the sensitivity to different wavelengths varies from species to species and with the experimental conditions (Liu et al, 2014 ), although the mechanisms involved in these differential responses are not yet fully understood (Demotes-Mainard et al, 2016 ). Regarding leaves, both the total leaf area and the specific leaf area were higher in seedlings grown under red light.…”

“…Stimulating the production of secondary metabolites by different light conditions in vitro is one of the simplest methods to increase the production of bioactive compounds of medicinal and economic importance (Kubica et al, 2020 ; Manivannan et al, 2021 ). The effects of different light spectra on the accumulation of secondary metabolites were evaluated in B. gaudichaudii with satisfactory results, showing that higher amounts of psoralen were produced in leaves of seedlings grown under the B/R 1:1 light, followed by plants exposed to B/R 3:1 and then to blue light, while the highest concentrations of bergapten were observed under blue or B/R 3:1 light ( Figure 8 ).…”

Light and Plant Growth Regulators on In Vitro Proliferation

“…BL is mostly considered to be able to increase leaf growth, photosynthetic pigment synthesis, chloroplast development and stomatal opening, soluble proteins and carbohydrates and dry matter content and to inhibit stem and root elongation, while RL enhances stem growth and carbohydrate accumulation [ 41 , 50 , 87 , 158 ]. In Scrophularia kakudensis , BL imposed a stressful environment that resulted in the activation of several proteins related to stress tolerance, photosynthesis, gene regulation, post-translational modification and secondary metabolism [ 169 ]. The improvement in the leaf characteristics induced by the addition of BL to RL seem to indicate a better quality of micropropagated plantlets, which in turn may also improve acclimation [ 2 , 170 ].…”

Linkages between stomatal density and minor leaf vein density across different altitudes and growth forms

“…A stable linkage between stomata and vein suggests that maintaining water dynamic stability is more important for shrubs and herbs. Different from strategy for rapid growth in trees, shrubs and herbs may prefer to maintain a balance of water supply and demand within the leaves, thus providing a stable growth environment, indicating a conservative strategy ( Brodribb and Jordan, 2011 ; Manivannan et al., 2021 ). Moreover, SD and VLA of herbs showed a significant coordination in each altitudinal gradient, but insignificant altitudinal trends in both shrubs and trees ( Supplementary Table S3 ).…”