Enhancement of root sulfur metabolic pathway by overexpression of OAS-TL3 to increase total soybean seed protein content.

Sulfur is essential for plant growth, and the uptake of sulfate by plant roots is the primary source of plant sulfur. Previous studies have shown that the OAS-TL gene is a key enzyme in the sulfur metabolic pathway and regulates cysteine (Cys) synthase production. However, the interaction mechanism of the glycine max OAS-TL3 Cys synthase (OAS-TL3) gene on soybean root morphology construction and seed protein accumulation is unclear. This study shows that mutant M18 has better root growth and development, higher seed protein content, and higher methionine (Met) content in sulfur-containing amino acids than wild-type JN18. By transcriptome sequencing, the differentially expressed OAS-TL3 gene was targeted in the mutant M18 root line. The relative expression of the OAS-TL3 gene in roots, stems, and leaves during the seedling, flowering, and bulking stages of the OAS-TL3 gene overexpression lines is higher than that of the recipient material. Compared to the recipient material JN74, the enzymatic activities, Cys, and GSH contents of OAS-TL are higher in the sulfur metabolic pathway of seedling roots. The receptor material JN74 is exogenously applied with different concentrations of reduced glutathione. The results demonstrate a positive correlation between reduced glutathione on total root length, projected area, surface area, root volume, total root tip number, total bifurcation number, and total crossing number. The Met and total protein contents of sulfur-containing amino acids in soybean seeds of the OAS-TL3 gene overexpression lines are higher than those of the recipient material JN74, while the gene-edited lines show the opposite results. In conclusion, the OAS-TL3 gene positively regulates soybean root growth, root activity, and the content of Met in the seeds through the OAS-TL-Cys-GSH pathway. It breaks the limitation of other amino acids and facilitates the increase of total seed protein content. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01348-y.

The GmXTH1 gene improves drought stress resistance of soybean seedlings.

In order to study the role of GmXTH1 gene in alleviating drought stress, soybean seeds with GmXTH1 gene were transferred by T4 treated with PEG6000 concentration of 0%, 5%, 10%, and 15% respectively. The germination potential, germination rate, germination index, and other indicators were measured. The results showed that the germination potential, germination rate, and germination index of OEA1 and OEA2 strains overexpressed in T4 generation were significantly higher than those of the control material M18. After 0-day, 7-day, and 15-day drought stress, the analysis of seedling phenotypes and root-shoot of different T4 generation transgenic soybean lines showed that under stress conditions, the growth of GmXTH1 overexpression material was generally better than that of the control material M18. The growth of GmXTH1 interference expression material was generally worse than that of the control material M18, with significant differences in plant phenotypes. The root system of GmXTH1 overexpressed material was significantly developed compared with that of the control material M18. The analysis of physiological and biochemical indexes showed that the relative water content and the activity of antioxidant enzymes (superoxide dismutase and peroxidase) of GmXTH1 transgenic soybean material were significantly higher than those of the control material M18, and the accumulation of malondialdehyde was lower under the same stress conditions at seedling stage. Fluorescence quantitative PCR assay showed that the relative expression of GmXTH1 gene in transgenic soybean was significantly increased after drought stress. The results showed that the overexpression of GmXTH1 could increase the total root length, surface area, total projection area, root volume, average diameter, total cross number, and total root tip number, thereby increasing the water intake and reducing the transpiration of water content in leaves, thus reducing the accumulation of MDA and producing more protective enzymes in a more effective and prompt way, reducing cell membrane damage to improve drought resistance of soybean.

Processing and Characterization of Refractory Quaternary and Quinary High-Entropy Carbide Composite.

Quaternary high-entropy ceramic (HEC) composite was synthesized from HfC, Mo2C, TaC, and TiC in pulsed current processing. A high-entropy solid solution that contained all principal elements along with a minor amount of a Ta-rich phase was observed in the microstructure. The high entropy phase and Ta-rich phase displayed a face-centered cubic (FCC) crystal structure with similar lattice parameters, suggesting that TaC acted as a solvent carbide during phase evolution. The addition of B4C to the quaternary carbide system induced the formation of two high-entropy solid solutions with different elemental compositions. With the increase in the number of principal elements, on the addition of B4C, the crystal structure of the HEC phase transformed from FCC to a hexagonal structure. The study on the effect of starting particle sizes on the phase composition and properties of the HEC composites showed that reducing the size of solute carbide components HfC, Mo2C, and TiC could effectively promote the interdiffusion process, resulting in a higher fraction of a hexagonal structured HEC phase in the material. On the other hand, tuning the particle size of solvent carbide, TaC, showed a negligible effect on the composition of the final product. However, reducing the TaC size from -325 mesh down to <1 µm resulted in an improvement of the nanohardness of the HEC composite from 21 GPa to 23 GPa. These findings suggested the possibility of forming a high-entropy ceramic phase despite the vast difference in the precursor crystal structures, provided a clearer understanding of the phase transformation process which could be applied for the designing of HEC materials.

Identification of the Function of the Pathogenesis-Related Protein GmPR1L in the Resistance of Soybean to Cercospora sojina Hara.

Pathogenesis-related proteins, often used as molecular markers of disease resistance in plants, can enable plants to obtain systemic resistance. In this study, a gene encoding a pathogenesis-related protein was identified via RNA-seq sequencing analysis performed at different stages of soybean seedling development. Because the gene sequence showed the highest similarity with PR1L sequence in soybean, the gene was named GmPR1-9-like (GmPR1L). GmPR1L was either overexpressed or silenced in soybean seedlings through Agrobacterium-mediated transformation to examine the resistance of soybean to infection caused by Cercospora sojina Hara. The results revealed that GmPR1L-overexpressing soybean plants had a smaller lesion area and improved resistance to C. sojina infection, whereas GmPR1L-silenced plants had low resistance to C. sojina infection. Fluorescent real-time PCR indicated that overexpression of GmPR1L induced the expression of genes such as WRKY, PR9, and PR14, which are more likely to be co-expressed during C. sojina infection. Furthermore, the activities of SOD, POD, CAT, and PAL were significantly increased in GmPR1L-overexpressing soybean plants after seven days of infection. The resistance of the GmPR1L-overexpressing lines OEA1 and OEA2 to C. sojina infection was significantly increased from a neutral level in wild-type plants to a moderate level. These findings predominantly reveal the positive role of GmPR1L in inducing resistance to C. sojina infection in soybean, which may facilitate the production of improved disease-resistant soybean cultivars in the future.

A high-entropy B4(HfMo2TaTi)C and SiC ceramic composite.

A multicomponent composite of refractory carbides, B4C, HfC, Mo2C, TaC, TiC and SiC, of rhombohedral, face-centered cubic (FCC) and hexagonal crystal structures is reported to form a single phase B4(HfMo2TaTi)C ceramic with SiC. The independent diffusion of the metal and nonmetal atoms led to a unique hexagonal lattice structure of the B4(HfMo2TaTi)C ceramic with alternating layers of metal atoms and C/B atoms. In addition, the classical differences in the crystal structures and lattice parameters among the utilized carbides were overcome. Electron microscopy, X-ray diffraction and calculations using density functional theory (DFT) confirmed the formation of a single phase B4(HfMo2TaTi)C ceramic with a hexagonal close-packed (HCP) crystal structure. The DFT based crystal structure prediction suggests that the metal atoms of Hf, Mo, Ta and Ti are distributed on the (0001) plane in the HCP lattice, while the carbon/boron atoms form hexagonal 2D grids on the (0002) plane in the HCP unit cell. The nanoindentation of the high-entropy phase showed hardness values of 35 GPa compared to the theoretical hardness value estimated based on the rule of mixtures (23 GPa). The higher hardness was contributed by the solid solution strengthening effect in the multicomponent hexagonal structure. The addition of SiC as the secondary phase in the sintered material tailored the microstructure of the composite and offered oxidation resistance to the high-entropy ceramic composite at high temperatures.

Correction: A high-entropy B4(HfMo2TaTi)C and SiC ceramic composite.

Correction for 'A high-entropy B4(HfMo2TaTi)C and SiC ceramic composite' by Hanzhu Zhang et al., Dalton Trans., 2019, DOI: 10.1039/c8dt04555k.

Aluminium matrix tungsten aluminide and tungsten reinforced composites by solid-state diffusion mechanism.

In-situ processing of tungsten aluminide and tungsten reinforced aluminium matrix composites from elemental tungsten (W) and aluminium (Al) was investigated by thermal analysis and pulsed current processing (PCP). The formation mechanism of tungsten aluminides in 80 at.% Al-20 at.% W system was controlled by atomic diffusion. The particle size of W and Al in the starting powder mixture regulated the phase formation and microstructure. PCP of micron sized elemental Al and W resulted in formation of particulate reinforcements, W, Al4W and Al12W, dispersed in Al matrix. W particles were surrounded by a ~3 µm thick dual-layer structure of Al12W and Al4W. The hardness of Al matrix, containing Al12W reinforcements, was increased by 50% compared to pure Al, from 0.3 GPa to 0.45 GPa and W reinforcements showed a hardness of 4.35 GPa. On PCP of 80 at.% Al-20 at.% W mixture with particle size of W and Al ~70 nm, resulted in formation of Al4W as major phase along with small fractions of Al5W and unreacted W phase. This suggested strongly that the particle size of the starting elemental Al and W could be the controlling parameter in processing and tailoring of phase evolution, microstructure of particulate reinforced Al matrix composite.