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We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 μmol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors.
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http://dx.doi.org/10.1016/j.plaphy.2015.01.008 | DOI Listing |
Pestic Biochem Physiol
November 2025
School of Life Sciences, Chongqing University, Chongqing 401331, China; Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China; Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing, China. Electronic add
Metarhizium acridum is a typical filamentous fungus that has been widely used to control grasshoppers, locusts, and crickets. Genetic engineering is a common strategy to enhance its virulence, conidiation, and stress tolerance. Here, we report that the M.
View Article and Find Full Text PDFPhysiol Mol Biol Plants
July 2025
Department of Plant Breeding, Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute (NSTRI), Karaj, Iran.
The medicinal plant is known for its rich secondary metabolite content, which plays a critical role in its therapeutic properties. This study investigates the impact of UV-B radiation on the biosynthesis of secondary metabolites, including phenolic compounds, flavonoids, terpenes, carotenoids, and lycopene, as well as the expression of key biosynthetic genes (, , , , and ) in . Plants were exposed to UV-B radiation for 1 and 2 h, and metabolite content and gene expression were measured at intervals of 3, 6, 9, and 12 h post-exposure.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Department of Immunology, University of Oldenburg, Oldenburg 26129, Germany.
Environmental stimuli, including the exposure to ultraviolet (UV)-B light, are known to play a role in the modulation of immune-mediated mechanisms in multiple sclerosis (MS). In experimental autoimmune encephalomyelitis (EAE), we have shown that UV-B irradiation ameliorates disease outcome by regulatory T cells (Treg) expansion. Moreover, the UV-B-mediated induction of Treg numbers was also observed in MS.
View Article and Find Full Text PDFPhysiol Plant
September 2025
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
Climate-driven abiotic stresses, responsible for approximately 50% of global crop yield losses, are putting agriculture under increasing pressure, demanding smarter ways to strengthen plants' natural defenses beyond genetic modification. Hydrogen peroxide (HO), long recognized as a key signaling molecule, plays a powerful role in helping plants cope with environmental stress. This review deciphers the mechanistic basis of HO-mediated capacity enhancement under diverse stresses (drought, salinity, heavy metals, heat, cold) while also addressing climate-intensified challenges like waterlogging and ultraviolet (UV) radiation.
View Article and Find Full Text PDFPlants (Basel)
August 2025
Institute for Interdisciplinary Research, Faculty of Food Engineering, Tourism and Environmental Protection, "Aurel Vlaicu" University of Arad, 2 Elena Dragoi St., 310330 Arad, Romania.
Tomato fruit () is a valuable agricultural crop worldwide due to its nutritional value and culinary applications, making it one of the most widely consumed vegetables in the human diet. However, excessive solar UV-B radiation represents a significant factor in decreasing productivity, marketable yields, and fruit quality in tomato crops by causing damage to both DNA and the photosynthetic system, as well as chlorophyll degradation. The application of silicon nanoparticles has been shown to increase tolerance to abiotic stressors, including enhanced UV-B radiation.
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