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Rice is one of the plants proven to possess antioxidant, anti-inflammatory, anti-proliferative, and whitening properties, making it one of the most beneficial plants in this regard. This study aimed to introduce a novel natural cosmetic and pharmaceutical product based on rice callus as a source of active ingredients that can inhibit skin melanoma cell (B16F10) proliferation and brighten the skin. The 2,4-D hormone at concentrations of 1 µg/mL and 1.5 µg/mL was used to induce rice callus formation. Rice callus extracts were then prepared using aqueous and ethanolic solvents, with a concentration of 1 mg/mL used for characterization tests. To determine the optimal hormone concentration, the phenols/flavonoids, antioxidant activity, proteins, and carbohydrates in the extracts were measured. The optimal concentration of the hormone was found to be 1 µg/mL. Finally, the anti-melanocyte and skin-whitening activity of the extracts was assessed through measurements of their cytotoxicity and inhibition of melanin synthesis-related enzymes. Cellular cytotoxicity measurements revealed that the ethanolic extract induced more cytotoxicity than the aqueous extract, with IC50 values of 566.3 µg/mL for the ethanolic extract and 1327 µg/mL for the aqueous extract. Skin-whitening-related tests demonstrated that the extracts were 1.7 times more effective than arbutin in inhibiting factors that cause hyperpigmentation. The aqueous extract achieved 85% inhibition of melanin biosynthesis at a concentration of 3200 µg/mL, compared to 68% for the ethanolic extract and 50% for arbutin. Based on these findings, rice callus extract can be introduced as a new, effective substance for skin-lightening and anti-melanocyte products in cosmeceutical and pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Simple Summary: Climate change is currently threatening agriculture all around the world, resulting in a lack of water and restricting the growth of plants, especially rice. Rice production decreases with the increase in temperature. An improvement in fundamental knowledge is necessary to comprehend plant adaptation mechanisms as responses to heat stress. Physiological and anatomical responses of Khao Dawk Mali 105 (KDML105) rice to artificial heat stress were studied. Our findings offer useful data for projects aimed at improving heat stress tolerance in rice to enhance long-term global food security. Global warming is a serious problem, with significant negative impacts on agricultural productivity. To better understand plant anatomical adaptation mechanisms as responses to heat stress, improved basic knowledge is required. This research studied the physiological and anatomical responses of Khao Dawk Mali 105 (KDML105) to artificial heat stress. Dehusked seeds were sterilized and cultured on Murashige and Skoog (MS) medium, supplemented with 3 mg/L 2,4-Dichlorophenoxyacetic acid (2,4-D) for callus induction. The cultures were maintained at 25 °C and 35 °C for 4 weeks, while the other culture was treated with heat shock at 42 °C for 1 week before further incubation at 25 °C for 3 weeks. Results revealed that elevated temperatures (35 °C and 42 °C) adversely impacted seedling growth. Plant height, root length, leaf number per plant, fresh and dry weight, chlorophyll a, chlorophyll b and total chlorophyll content decreased after heat stress treatment, while malondialdehyde (MDA) and electrolyte leakage percentage significantly increased, compared to the control. Heat stress induced ROS accumulation, leading to lipid peroxidation and membrane instability. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) results also confirmed negative correlations between MDA, electrolyte leakage and other parameters. MDA content and electrolyte leakage are effective indicators of heat stress in rice. Surface anatomical responses of rice seedlings to heat stress were studied but significant alterations were not observed, and heat stress had no significant negative effects on KDML105 calli. Size and mass of calli increased because heat stress stimulated gene expression that induced thermotolerance. Our results provide useful information for rice breeding and heat stress tolerance programs to benefit long-term global food security. [ABSTRACT FROM AUTHOR]

Highlights: [•] We expressed a recombinant major capsid protein (rMCP) of rock bream iridovirus in rice callus. [•] Fish immunized orally with rMCP underwent successful induction of antibodies and were protected against viral challenge. [•] Transgenic single-cell cultures offer advantages over whole-plant systems with high level containment. [•] Plant-based oral administration protocol could be used as an effective (less labor and stress) means of accomplishing practical vaccine trials. [Copyright &y& Elsevier]

Ultrasound acts as an alternative stress on cells or tissues. In this study it is aimed to investigate the effect of ultrasonic stimulation on the growth and proliferation of Oryza sativa Nipponbare cells (rice callus) in suspension culture. After the samples were stimulated by ultrasound at 28 kHz, we measured their growth and proliferation by using a colorimetric MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay as well as fresh weights of the cells. Growth curves were obtained by fresh weights in the suspension culture after ultrasonic agitation for different time from 2 to 120 s. In MTT method, the optical density was determined at 570 nm in the cell suspension on 10 days after the ultrasonic agitation. Up to 5 s agitation OD570 increased; it decreased for more prolonged stimulation. We found that ultrasonic stimulation could promote the growth and proliferation of O. sativa Nipponbare cells in suspension culture with the optimal stimulation of 5 s, while with longer agitation, its growth and proliferation was inhibited. The mechanism may be that the ultrasound activated or destroyed the cellular structure, such as cell membrane, cytoskeleton and mitochondria in which many enzymes and ion channels are affected. In addition, the enhancement of cell wall and cell membrane fluidity might be one of the factors to promote the cell growth in 5-s ultrasonic stimulation. [Copyright &y& Elsevier]

Background: β-carotene (provitamin A) is an important target for biofortification of crops as a potential solution to the problem of vitamin A deficiency that is prevalent in developing countries. A previous report showed that dominant expression of splicing variants in the Orange (Or) gene causes β-carotene accumulation in cauliflower curd. In this study, we focused on a putative orthologue of the cauliflower or gene in rice, Osor, and attempt to accumulate β-carotene in rice callus by modification of the Osor gene via genome editing using CRISPR/Cas9. Findings: CRISPR/Cas9 vectors for the Osor gene were constructed and transformed into rice calli. Some transformed calli showed orange color due to β-carotene hyper-accumulation. Molecular analyses suggest that orange-colored calli are due to an abundance of in-frame aberrant Osor transcripts, whereas out-of-frame mutations were not associated with orange color. Conclusions: We demonstrate that directed gene modification of the Osor gene via CRISPR/Cas9-mediated genome editing results in β-carotene fortification in rice calli. To date, golden rice, which accumulates β-carotene in rice endosperm, has been developed by conventional transgenic approaches. Our results suggest an alternative approach to enhancing β-carotene accumulation in crops. [ABSTRACT FROM AUTHOR]