DsLCYB Directionally Modulated β-Carotene of the Green Alga Dunaliella salina under Red Light Stress

Abstract

Carotenoids' is a general term for a class of valuable, natural fat-soluble pigments that are distributed widely in bacteria, fungi, algae [1][2][3][4], and photosynthetic plants. In humans, however, carotenoids can only be obtained from food. Studies to elucidate the regulation of carotenoid composition in model species and accumulate target components are critical because carotenoids have important physiological functions, including an antioxidant role, immune regulation, and prevention of cardiovascular disease, certain types of cancer, eye-related diseases, and light-induced skin damage [5].Carotenoids are divided into two major classes: xanthophylls, which contain oxygen, and carotenes, which mainly consist of hydrocarbons and no oxygen. β-Carotene, the most important and effective vitamin A precursor among the carotenes, plays a vital role in human health, protecting against age-related degenerative diseases, cardiovascular disease, vitamin A deficiency (VAD), and certain cancers [6,7]. β-Carotene is catalyzed directly by β-carotene hydroxylase (BCH) to generate β-cryptoxanthin, an antioxidant that may help prevent free radical damage to biomolecules including lipids, proteins, and nucleic acids [8,9]. Studies in animal models and humans have also shown that β-cryptoxanthin derived from food has better in vitro bioavailability than α-carotene and βcarotene. Zeaxanthin, a direct product of cryptoxanthin, is a new type of oil-soluble natural pigment, which often coexists with lutein, β-carotene, and β-cryptoxanthin in nature to form a carotenoid mixture. Zeaxanthin prevents the oxidation of lipids and vitamins in food and prolongs the preservation period of food, making it an ideal natural food preservative [10,11]. Recognition of the importance of the rich variety and functional diversity of carotenoids has resulted in increased demand and focus on how to improve the production of natural carotenoids.The accumulation of certain metabolites often affects the composition of the carotenoid biosynthesis pathway. The cyclization reaction of lycopene converts lycopene into α-carotene and β-carotene and is an essential reaction for the production of β-carotene, which has important physiological functions in algae [12,13]. The lycopene β cyclase (LCYB) gene is related directly to the production of β-carotene, and therefore it is necessary to study this enzyme. It has been reported that modification of the LCYB gene affects the accumulation of its metabolites and the response to abiotic stress in some photosynthetic plants. For example, in transgenic sweet potatoes, IbLCYB2 was shown to enhance abiotic stress tolerance and carotenoid content, including α-carotene, β-carotene, lutein, βcryptoxanthin, and zeaxanthin [14]. Heterologous overexpression of DcLCYB1 in carrots was reported to increase Carotenoids, which are natural pigments found abundantly in wide-ranging species, have diverse functions and high industrial potential. The carotenoid biosynthesis pathway is very complex and has multiple branches, while the ac...

Regulation of a novel DsGATA1 from Dunaliella salina on the synthesis of carotenoids under red light

“…The interfering fragment was obtained by chemical synthesis. The overexpressed and silenced sequences of DsGATA1 were digested with Xho I and Kpn I and inserted into the transgenic vector PGreen0029 (Figure S1 a) by the method of Lan (Lan et al 2022); the sequences were in Table S2. And the RNA of the overexpressed, wild-type, and interference strains was extracted for qRT-PCR to determine the expression of their DsGATA1 genes.…”

“…The growth curves of D. salina were plotted by taking 3 mL of algal solution every day and measuring the absorbance value at a wavelength of 654 nm with a spectrophotometer (Lan et al 2022).…”