Exposure to ultraviolet B radiation (UV-B) stress can have serious effects on the growth and development of plants. Germin-like proteins (GLPs) may be involved in different abiotic and biotic stress responses in different plants, but little is known about the role of GLPs in UV-B stress response and acclimation in plants. In the present study, knockout of GLP 8–14 (OsGLP1) using the CRISPR/Cas9 system resulted in mutant rice (Oryza sativa L.) plants (herein called glp1) that exhibited UV-B-dependent formation of lesion mimic in leaves. Moreover, glp1 grown under solar radiation (including UV-B) showed decreased plant height and increased leaf angle, but we observed no significant differences in phenotypes between wild-type (WT) plants and glp1 grown under artificial light lacking UV-B. Fv/Fm, Y (II) and the expression of many genes, based on RNA-seq analysis, related to photosynthesis were also only reduced in glp1, but not in WT, after transfer from a growth cabinet illuminated with artificial white light lacking UV-B to growth under natural sunlight. The genes-associated with flavonoid metabolism as well as UV resistance locus 8 (OsUVR8), phytochrome interacting factor-like 15-like (OsPIF3), pyridoxal 5′-phosphate synthase subunit PDX1.2 (OsPDX1.2), deoxyribodipyrimidine photolyase (OsPHR), and deoxyribodipyrimidine photolyase family protein-like (OsPHRL) exhibited lower expression levels, while higher expression levels of mitogen-activated protein kinase 5-like (OsMPK3), mitogen-activated protein kinase 13-like (OsMPK13), and transcription factor MYB4-like (OsMYB4) were observed in glp1 than in WT after transfer from a growth cabinet illuminated with artificial white light to growth under natural sunlight. Therefore, mutations in OsGLP1 resulted in rice plants more sensitive to UV-B and reduced expression of some genes for UV-B protection, suggesting that OsGLP1 is involved in acclimation to UV-B radiation.
The public is already aware that nitrate pollution caused by nutrient runoff from farms is harmful to aquatic life and human health, and there is an urgent need for a product/technology to solve this problem. A biochar adsorbent was synthesized and used to remove nitrate ions from aqueous media based on spent mushroom compost (SMC), pre-treated with iron (III) chloride hexahydrate and pyrolyzed at 600 °C. The surface properties and morphology of SMCB/Fe were investigated using Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The effect of main parameters such as the adsorbent dosages, pH of the solutions, contact times, and ion concentrations on the efficiency of nitrate removal was investigated. The validity of the experimental method was examined by the isothermal adsorption and kinetic adsorption models. The nitrate sorption kinetics were found to follow the pseudo-second-order model, with a higher determination coefficient (0.99) than the pseudo-first-order (0.86). The results showed that the maximum percentage of nitrate adsorption was achieved at equilibrium pH 5–7, after 120 min of contact time, and with an adsorbent dose of 2 g L−1. The highest nitrate adsorption capacity of the modified adsorbent was 19.88 mg g−1.