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To explore the role of glutathione S-transferase gene (GST) in the accumulation of anthocyanin in Brassica juncea, one GST gene related to the anthocyanidin accumulation was cloned from near-isogenic lines of B. juncea with purple stalk and green stalk, and named as BjGSTF12. In this study, the bioinformatics characteristics of BjGSTF12 encoding protein and promoter were analyzed, the expression level of BjGSTF12 and the relationship with total anthocyanidin content were analyzed in B. juncea lines with purple stalk and green stalk. The results were as follow: (1) BjGSTF12 genes from B. juncea were successfully cloned, whose the full length of BjGSTF12 in genome and cDNA was 808 bp and 651 bp, encoding a protein of 216 amino acids. The BjGSTF12 contained the typical domains of GST proteins, namely GST_N and GST_C. However, their sequences of BjGSTF12 did not exhibit any differences between the two lines of B. juncea. (2) BjGSTF12 was closely related to AtGSTF12 in Arabidopsis, and both belonged to the φ subfamily of GST family. (3) The BjGSTF12 promoter sequences were cloned from two Brassica juncea strains of green stalk and purple stalk, and they exhibited four base mutations/insertions. However, the types and numbers of cis-acting elements did not show obvious differences between the two strains, including nine MYB transcription factor binding sites, one hormone response element, and three abiotic corresponding elements. (4) The total anthocyanidin content in B. juncea of purple stalk was significantly higher than that in green stalk ones, and the expression levels of BjGSTF12 in two lines were found to be similar to the total anthocyanidin content in both lines. (5) Protein interaction network analysis revealed that BjGSTF12 may interact with the key enzymes of anthocyanidin biosynthesis, glycosylation modification, and transporter proteins. In summary, BjGSTF12 is likely to play a key role in the accumulation of anthocyanidin in B. juncea by regulating its biosynthesis, modification, and transportation through interactions with other proteins. This study provides a theoretical reference for further study on the function of GST and the mechanism of anthocyanidin accumulation in B. juncea.

To further explore the possibility of the electrochemical reduction of NaBO2 into NaBH4, the electrochemical reduction of NaBO2 into NaBH4 was fulfilled with pulse voltage using the Eu-Co-Ni-B coating electrode. A simple electroless plating technique was used to prepare the Eu-Co-Ni-B coating electrode. It has been proved that NaBO2 was converted into NaBH4 by electrochemical analysis method. The results showed that the method of detection and quantitative analysis of NaBH4 with gold electrode was feasible (R2=0.98). When the reverse pulse voltage was + 0.5 V, the forward pulse voltage was −1.5 V, the reverse pulse duration was 2 s and the forward pulse duration was 2 s, the concentration of NaBH4 reaches a maximum of 1.25 × 10−4 mol/L. With the continuous increase of electrolytic time, the concentration of NaBH4 shows a trend of increasing first and then decreasing. When the electrolytic time was 2 h, the maximum concentration of NaBH4 reaches 1.61 × 10−4 mol/L. [ABSTRACT FROM AUTHOR]

Compared with sole nitrogen (N), the nutrition mixture of ammonium (NH4+) and nitrate (NO3–) is known to better improve crop yield and quality. However, the mechanism underlying this improvement remains unclear. In the present study, we analyzed the changes in nutrient solution composition, content of different N forms in plant tissues and exudates, and expression of plasma membrane (PM) H+-ATPase genes (HAs) under different NH4+/NO3– ratios (0/100, 10/90, 25/75, 50/50 as control, T1, T2, and T3) in flowering Chinese cabbage. We observed that compared with the control, T1 and T2 increased the economical yield of flowering Chinese cabbage by 1.26- and 1.54-fold, respectively, whereas T3 significantly reduced plant yield. Compared with the control, T1–T3 significantly reduced the NO3– content and increased the NH4+, amino acid, and soluble protein contents of flowering Chinese cabbage to varying extents. T2 significantly increased the N use efficiency (NUE), whereas T3 significantly decreased it to only being 70.25% of that of the control. Owing to the difference in N absorption and utilization among seedlings, the pH value of the nutrient solution differed under different NH4+/NO3– ratios. At harvest, the pH value of T2 was 5.8; in the control and T1, it was approximately 8.0, and in T3 it was only 3.6. We speculated that appropriate NH4+/NO3– ratios may improve N absorption and assimilation and thus promote the growth of flowering Chinese cabbage, owing to the suitable pH value. On the contrary, addition of excessive NH4+ may induce rhizosphere acidification and ammonia toxicity, causing plant growth inhibition. We further analyzed the transcription of PM H+-ATPase genes (HAs). HA1 and HA7 transcription in roots was significantly down-regulated by the addition of the mixture of NH4+ and NO3–, whereas the transcription of HA2 , HA9 in roots and HA7 , HA8 , and HA10 in leaves was sharply up-regulated by the addition of the mixture; the transcription of HA3 was mainly enhanced by the highest ratio of NH4+/NO3–. Our results provide valuable information about the effects of treatments with different NH4+/NO3– ratios on plant growth and N uptake and utilization. [ABSTRACT FROM AUTHOR]

To investigate the effect of ChCl-urea eutectic solvent on the content of electrodeposited alloy film and improve the corrosion resistance of binary magnesium alloy, the Eu-Mg-Co alloy film was prepared by constant potential electrolysis in a 353 K ChCl-urea eutectic solvent to optimize the composition and corrosion resistance of Mg alloy. Cyclic voltammetry was used to study the electrochemical behavior of ChCl-urea and the addition of metal elements. The cyclic voltammetry curve on the Pt electrode shows that Co(II) + 2e→Co(0) was a one-step irreversible reaction, and the transfer coefficient α of Co(II) on the Pt electrode and the diffusion coefficient D0 were calculated. The rare earth element Eu and the metal Mg had a relatively low deposition potential, and it was difficult to separately deposit a single element alloy film, but a co-deposition could be induced by Co(II) to obtain a multi-alloy film. The electrodeposition was performed by potentiostatic chronoamperometry in different potentials and different compositions. The alloy film was analyzed and characterized by EDS analysis and SEM. The alloy film was subjected to Tafel test, and the self-corrosion current and potential of the alloy film in NaCl solution were obtained by extrapolation. The results show that the transfer coefficient of Co(II) on the Pt electrode was α=0.093, and the diffusion coefficient D0 was 1.177 x 10-5 cm²/s. The EDS results show that the Eu content was the highest in the alloy film when the deposition potential was --1.18 V and the plating solution ratio was 0.04 mol/L CoCl2+0.04 mol/L MgCl2 + 0.03 mol/L Eu(NO3)3. Eu-Mg-Co had good corrosion resistance. The Eu-Mg-Co alloy film with fine and uniform coating grain was obtained. The corrosion resistance of the ternary alloy film with rare earth Eu element was better than that of Co-Mg binary alloy film. [ABSTRACT FROM AUTHOR]

An asymmetric organocatalytic quadruple cascade reaction was developed for the stable and sterically hindered 2-hydroxychalcones and substituted cinnamaldehydes. This process proceeded through an oxa-Michael-Michael-Michael-aldol condensation to afford highly functionalized tetrahydro-6 H-benzo[ c]chromene derivatives with high diastereoselectivity and enantioselectivity (>99 % ee). The structure of adduct 4g with five stereocenters was unambiguously confirmed by single-crystal X-ray diffraction, and valuable mass spectrometry data provided direct support for the proposed reaction mechanism. [ABSTRACT FROM AUTHOR]

An organophosphane catalyst derived from L-proline was shown to be a very effective catalyst for asymmetric Michael addition reactions of various chalcones to cyclic ketones including both cyclohexanone and cyclopentanone. The corresponding adducts could be obtained in high yields (up to 91 %) and with excellent enantioselectivities (up to 99 % ee) and diastereomeric ratios (up to >99:1). A possible catalytic mechanism, based on 31P NMR and ESI-MS observations, for this organophosphane-catalyzed Michael addition has been proposed. [ABSTRACT FROM AUTHOR]

Compared with sole nitrogen (N), the nutrition mixture of ammonium (NH 4 + ) and nitrate (NO 3 - ) is known to better improve crop yield and quality. However, the mechanism underlying this improvement remains unclear. In the present study, we analyzed the changes in nutrient solution composition, content of different N forms in plant tissues and exudates, and expression of plasma membrane (PM) H + -ATPase genes ( HAs ) under different NH 4 + /NO 3 - ratios (0/100, 10/90, 25/75, 50/50 as control, T1, T2, and T3) in flowering Chinese cabbage. We observed that compared with the control, T1 and T2 increased the economical yield of flowering Chinese cabbage by 1.26- and 1.54-fold, respectively, whereas T3 significantly reduced plant yield. Compared with the control, T1-T3 significantly reduced the NO 3 - content and increased the NH 4 + , amino acid, and soluble protein contents of flowering Chinese cabbage to varying extents. T2 significantly increased the N use efficiency (NUE), whereas T3 significantly decreased it to only being 70.25% of that of the control. Owing to the difference in N absorption and utilization among seedlings, the pH value of the nutrient solution differed under different NH 4 + /NO 3 - ratios. At harvest, the pH value of T2 was 5.8; in the control and T1, it was approximately 8.0, and in T3 it was only 3.6. We speculated that appropriate NH 4 + /NO 3 - ratios may improve N absorption and assimilation and thus promote the growth of flowering Chinese cabbage, owing to the suitable pH value. On the contrary, addition of excessive NH 4 + may induce rhizosphere acidification and ammonia toxicity, causing plant growth inhibition. We further analyzed the transcription of PM H + -ATPase genes ( HAs ). HA1 and HA7 transcription in roots was significantly down-regulated by the addition of the mixture of NH 4 + and NO 3 - , whereas the transcription of HA2 , HA9 in roots and HA7 , HA8 , and HA10 in leaves was sharply up-regulated by the addition of the mixture; the transcription of HA3 was mainly enhanced by the highest ratio of NH 4 + /NO 3 - . Our results provide valuable information about the effects of treatments with different NH 4 + /NO 3 - ratios on plant growth and N uptake and utilization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhu, Qi, Hao, Liu, Sun, Chen and Song.)