Effects of Different Short-Term UV-B Radiation Intensities on Metabolic Characteristics of Porphyra haitanensis

Abstract

The effects of ultraviolet (UV) radiation, particularly UV-B on algae, have become an important issue as human-caused depletion of the protecting ozone layer has been reported. In this study, the effects of different short-term UV-B radiation on the growth, physiology, and metabolism of Porphyra haitanensis were examined. The growth of P. haitanensis decreased, and the bleaching phenomenon occurred in the thalli. The contents of total amino acids, soluble sugar, total protein, and mycosporine-like amino acids (MAAs) increased under different UV-B radiation intensities. The metabolic profiles of P. haitanensis differed between the control and UV-B radiation-treated groups. Most of the differential metabolites in P. haitanensis were significantly upregulated under UV-B exposure. Short-term enhanced UV-B irradiation significantly affected amino acid metabolism, carbohydrate metabolism, glutathione metabolism, and phenylpropane biosynthesis. The contents of phenylalanine, tyrosine, threonine, and serine were increased, suggesting that amino acid metabolism can promote the synthesis of UV-absorbing substances (such as phenols and MAAs) by providing precursor substances. The contents of sucrose, D-glucose-6-phosphate, and beta-D-fructose-6-phosphate were increased, suggesting that carbohydrate metabolism contributes to maintain energy supply for metabolic activity in response to UV-B exposure. Meanwhile, dehydroascorbic acid (DHA) was also significantly upregulated, denoting effective activation of the antioxidant system. To some extent, these results provide metabolic insights into the adaptive response mechanism of P. haitanensis to short-term enhanced UV-B radiation.

UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings

“…Kusano et al [22] also demonstrated that carbon flux was dominant towards the shikimate pathway at the transcriptional level of the genes. Enhanced accumulation of secondary metabolites including lignin and flavonoids was proven as an early response against UVB stress [31][32][33][34][35] and was also observed in some plant species: rye [36], grapes [37], and cistus [38]. Our study carefully affords the probability that lignin and flavonoids feature both defensive and adaptive responses in an excessive UVB environment in terms of the increasing patterns in both younger (day 1) and older (day 5) stages and shows some accordance with previous observations.…”

Photosynthetic Protein-Based Edible Quality Formation in Various Porphyra dentata Harvests Determined by Label-Free Proteomics Analysis

“…Additionally, mycosporine-like amino acid (MAA) proteins unique to Porphyra increase throughout the harvest period and mitigate the effects of UV radiation and oxidative stress, promoting PSII D1 protein synthesis [ 42 ]. Previous research on Porphyra haitanensis reported that UV irradiation significantly increased the proline (Pro), serine (Ser), histidine (His), and alanine (Ala) content which, in turn, could offset stress-related cell damage, remove ROS, protect membrane integrity, enhance metabolic pathways, and increase the total sugar content [ 43 , 44 ]. These findings were consistent with our results (data not published).…”

The Mutational, Epigenetic, and Transcriptional Effects Between Mixed High-Energy Particle Field (CR) and 7Li-Ion Beams (LR) Radiation in Wheat M1 Seedlings

“…The increase of soluble sugar content and the enrichment of “starch and sucrose metabolism” pathway were also reported in rice under gamma rays, cosmic rays, and carbon-ion beams treatments ( Hwang et al, 2014 ), which is consistent with our result. The contents of soluble sugar, such as sucrose and D -glucose-6-phosphate, were increased in Porphyra haitanensis under UV-B exposure ( Fu et al, 2021 ). Combined with these studies, we suggested that the accumulation of soluble sugar and the activation of ROS scavenging processes might be the important processes for plants in response to IR irradiation.…”