LED-Induced Carotenoid Synthesis and Related Gene Expression in Brassica Microgreens

Abstract

In this study, various ratios of combined red, blue, and amber light-emitting diodes (rbaLEDs) were investigated for their effect on the expression of carotenoid biosynthetic genes and carotenoid accumulation in eight Brassica microgreens. Total and individual (β-carotene, lutein, α-carotene, neoxanthin, and violaxanthin) carotenoids were increased 20–44 and 10–55%, respectively, under dose-dependent increasing amber–blue light and decreasing red in most microgreens. Lipophilic 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power antioxidant activities were significantly increased under higher amber and blue light fractions, while oxygen radical absorbance capacity was generally decreased. Under rbaLED in mizuna (B. rapa) microgreens, the lycopene epsilon cyclase (LYCε) expression was 10–15-fold higher, which resulted in downstream accumulation of α-carotene and lutein. Lycopene beta cyclase (LYCβ) was not significantly changed, suggesting that β-carotene, violaxanthin and neoxanthin were mainly controlled by upstream phytoene synthase and branch-point LYCε. Increased beta-ring carotenoid hydroxylase (CHXβ) expression was also consistent with lutein accumulation. This study demonstrated for the first time that amber LED was involved in the regulatory mechanism of carotenoid biosynthesis, thus a potential novel approach to production of antioxidant-rich microgreens.

Manipulation of the Phytochemical Profile of Tenderstem® Broccoli Florets by Short Duration, Pre-Harvest LED Lighting

“…Genes that regulate carotenoid biosynthesis pathways have been shown to be partially influenced by light. However, the transcriptional regulation of carotenoid biosynthetic genes varies between species [ 25 ]; therefore, different species and cultivars respond independently to changes in light quality [ 7 , 8 ]. The results of this current study are consistent with the findings of Kopsell et al (2013, 2014) [ 10 , 11 ], where lutein and β-carotene content in sprouting broccoli responded similarly to light treatments.…”

“…Depending on the phytochemical of interest, careful selection of other environment parameters is integral, e.g., temperature when assessing glucosinolates, and water availability for tocopherols. Numerous studies have focused on the growth of a range of leafy crops, including salad leaves, microgreens and herbs [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. This study is the first to quantify the manipulation of phytochemical levels in a mature glasshouse grown vegetable brassica, using a period of LED lighting prior to harvest.…”

“…Exposure to blue light has been reported to have a beneficial effect on carotenoid, total phenolics [ 4 ] and GLS [ 5 , 6 ] in a number of plants, alongside increasing biomass. Although there are some commonalities in responses between plants, an increasing number of studies have shown that the response of plants to light quality is species and cultivar specific [ 7 , 8 ].…”

Bioeffector Pseudomonas fluorescens ZX Elicits Biosynthesis and Accumulation of Functional Ingredients in Citrus Fruit Peel: A Promising Strategy for a More Sustainable Crop

“…Importantly, these components have been demonstrated to be highly inducible. 10,12 Thus, citrus fruit peels could feasibly serve as rich and profitable sources for obtaining bioactive compounds highly valued in the food, health, pharmaceutical, and cosmetic fields, 1 where leveraging of citrus peels as a source of valuable products can contribute to a circular economy. Effective implementation of this proposal calls for efficacious, economical, and environmentally friendly techniques, such as the widely accepted use of BCAs or their derived molecules.…”

Raman Spectroscopy Applications in Grapevine: Metabolic Analysis of Plants Infected by Two Different Viruses

“…Plant extracts were prepared according to Alrifai et al (2021) , with slight modifications. Grapevine leaves were freeze-dried and maintained at −80°C; 25–30 mg of powdered material were extracted in 4 ml of an acetone:ethanol (1:1, v/v) solution and extracts were sonicated in a water bath for 15 min and incubated at room temperature for 4 h, with shaking at 400 rpm (Sky4 Shaking Incubator, Argo Lab).…”