A Golgi-Localized Sodium/Hydrogen Exchanger Positively Regulates Salt Tolerance by Maintaining Higher K+/Na+ Ratio in Soybean.

Salt stress caused by soil salinization, is one of the main factors that reduce soybean yield and quality. A large number of genes have been found to be involved in the regulation of salt tolerance. In this study, we characterized a soybean sodium/hydrogen exchanger gene GmNHX5 and revealed its functional mechanism involved in the salt tolerance process in soybean. GmNHX5 responded to salt stress at the transcription level in the salt stress-tolerant soybean plants, but not significantly changed in the salt-sensitive ones. GmNHX5 was located in the Golgi apparatus, and distributed in new leaves and vascular, and was induced by salt treatment. Overexpression of GmNHX5 improved the salt tolerance of hairy roots induced by soybean cotyledons, while the opposite was observed when GmNHX5 was knockout by CRISPR/Cas9. Soybean seedlings overexpressing GmNHX5 also showed an increased expression of GmSOS1, GmSKOR, and GmHKT1, higher K+/Na+ ratio, and higher viability when exposed to salt stress. Our findings provide an effective candidate gene for the cultivation of salt-tolerant germplasm resources and new clues for further understanding of the salt-tolerance mechanism in plants.

Facile Synthesis of Gold-Modified Platinum Catalysts with High Performance for Formic Acid Electro-oxidation.

A facile, eco-friendly method for the synthesis of gold/platinum catalysts through electrodeposition of platinum nanoparticles, followed by the deposition of solutions of HAuCl4 onto the surface of pre-prepared platinum for a galvanic replacement reaction, is reported. Different molar ratios of bimetallic structures of platinum and gold could be easily achieved and characterized by energy-dispersive X-ray spectroscopy, SEM, and XRD. Electrochemical measurements reveal that the electrocatalytic activities of these series of gold/platinum catalysts towards formic acid oxidation reaction are superior to that of pure platinum. In addition, the formic acid oxidation route is related to the molar ratio of gold to platinum, which can be ascribed to the influence of gold. The gold/platinum catalyst with a platinum to gold atomic ratio of 2.51:1 exhibits maximum activity. Moreover, this optimized molar ratio shows a highly stable electrocatalytic activity for CO antipoisoning effects. These experimental results suggest that the prepared gold/platinum catalysts have great potential for applications in fuel cells.