Search

The NAC transcription factors play an important regulatory role in plant growth and development. In order to explore the impact of NAC6 on carotenoid metabolism in postharvest mango fruit, this study investigated changes in the carotenoid contents as well as the expression of NAC6 and key enzymes involved in carotenoid synthesis and metabolism in the mature peel and pulp of 2 mango varieties, “Tainong” and “Jinhuang”, at commercial maturity, during postharvest storage under constant temperature (20 ℃), constant humidity (85%), and dark conditions. The results showed that both mango varieties contained α-carotene, lutein, β-carotene, β-cryptoxanthin, and zeaxanthin. Throughout the storage process, the expression of NAC6 in both mango varieties showed a continuous upward trend, reaching a peak in the late stage of storage, followed by a slight decline. Correlation analysis showed that NAC6 might induce the gene expression of 1-deoxy-D-xylulose-5-phosphate reductoisomerase, farnesyl pyrophosphate synthase, geranylgeranyl pyrophosphate synthase, phytoene synthase, phytoene desaturase, ζ-carotene desaturase, carotenoid isomerase, β-carotene hydroxylase, and violaxanthin de-epoxidase in mango fruit, while inhibiting the gene expression of lycopene β-cyclase, neoxanthin synthase, and 9-cis-epoxycarotenoid dioxygenase. The expression of NAC6 in the peel and pulp of “Tainong” mango was significantly negatively correlated with the gene expression of carotenoid cleavage dioxygenase (CCD), with correlation coefficients of −0.841 0 and −0.838 3, respectively. NAC6 might delay the degradation of carotenoids by inhibiting the expression of CCD. The results from this research provide an experimental basis for the postharvest storage and preservation of mango fruit as well as its quality control.

The yellow-fleshed loquat is abundant in carotenoids, which determine the fruit's color, provide vitamin A, and offer anti-inflammatory and anti-cancer health benefits. In this research, the impact of abscisic acid (ABA), a plant hormone, on carotenoid metabolism and flesh pigmentation in ripening loquat fruits was determined. Results revealed that ABA treatment enhanced the overall content of carotenoids in loquat fruit, including major components like β-cryptoxanthin, lutein, and β-carotene, linked to the upregulation of most genes in the carotenoid biosynthesis pathway. Furthermore, a transcription factor, EjWRKY6, whose expression was induced by ABA, was identified and was thought to play a role in ABA-induced carotenoid acceleration. Transient overexpression of EjWRKY6 in Nicotiana benthamiana and stable genetic transformation in Nicotiana tabacum with EjWRKY6 indicated that both carotenoid production and genes related to carotenoid biosynthesis could be upregulated in transgenic plants. A dual-luciferase assay proposed a probable transcriptional control between EjWRKY6 and promoters of genes associated with carotenoid production. To sum up, pre-harvest ABA application could lead to carotenoid biosynthesis in loquat fruit through the EjWRKY6-induced carotenoid biosynthesis pathway. [ABSTRACT FROM AUTHOR]

Choosing an appropriate drying method is crucial for producing dried cherry blossoms with desirable quality. This study is designed to assess the effects of seven different drying methods—hot-air drying (HAD), infrared hot-air drying (IHAD), catalytic infrared drying (CID), relative humidity drying (RHD), pulsed vacuum drying (PVD), microwave vacuum drying (MVD), and vacuum freeze drying (VFD)—on drying time and various attributes of cherry blossoms, such as appearance, bioactive compounds, antioxidant activity, α-glucosidase activity, and sensory properties. Our findings revealed that MVD recorded the shortest drying time, followed by PVD, CID, IHAD, RHD, HAD, and VFD. In qualities, VFD-dried petals exhibited superior appearance, bioactive compounds, antioxidant activity, and α-glucosidase inhibitory capability; MVD-dried petals were a close second. Furthermore, the quality of tea infusions prepared from the dried petals was found to be significantly correlated with the quality of the dried petals themselves. Regarding sensory attributes, VFD-dried petals produced tea infusions most similar in flavor and taste to those made with fresh petals and received the highest sensory evaluation scores, followed by MVD, PVD, RHD, CID, IHAD, and HAD. These results could offer a scientific foundation for the mass production of high-quality dried cherry blossoms in the future. [ABSTRACT FROM AUTHOR]

In the face of the fossil energy crisis, hydrogen energy has attracted widespread attention because of its cleanness and efficiency. Therefore, hydrogen production by water electrolysis has become a new research upsurge. This research mainly focused on the synthesis, characterization and application of Pt/Cu alloy catalyst. Pt/Cu alloy was synthesized by solvothermal method. The composition, structure and morphology of Pt/Cu alloy were characterized by XRD, SEM, TEM, EDS, XPS, etc, to explore the relationship between its structure and performance. The catalytic performance of Pt/Cu alloy under different electrolyte were tested by electrochemical test system. In 0. 5 mol/L H2SO4, the initial overpotential of Pt/Cu alloy is 20. 3 mV (at 10 mA ⋅ cm-2) and the Tafel is 37.56 mV ⋅ dec-1. At the same time, the initial overpotential and Tafel of Pt/Cu alloy are 35.0 mV (at 10 mA ⋅ cm-2) and 52. 12 mV ⋅ dec-1 respectively in 1 mol/L phosphate buffered saline (PBS). In addition, the initial overpotential and the Tafel of Pt/Cu alloy are 25. 3 mV (at 10 mA ⋅ cm-2) and 36. 82 mV ⋅ dec-1 respectively in 1 mol/L KOH. It can be found that Pt/Cu alloy exhibits better catalytic performance in acidic electrolyte. Moreover, further experiments show that the Pt/Cu alloy catalyst has high electrocatalytic activity surface area (30. 83 cm²) and good cycle stability in acidic electrolyte. [ABSTRACT FROM AUTHOR]