Facile Bioself-Assembled Crystals in Plants Promote Photosynthesis and Salt Stress Resistance

Salty soil is a global problem that has adverse effects on plants. We demonstrate that bioself-assembled molybdenum–sulfur (Mo–S) crystals formed by the foliar application of MoCl5 and cysteine augment the photosynthesis of plants treated with 200 mM salt for 7 days by promoting Ca2+ signal transduction and free radical scavenging. Reductions in glutathione and phytochelatins were attributed to the biosynthesized Mo–S crystals. Plants embedded with the Mo–S crystals and exposed to salty soil exhibited carbon assimilation rates, photosynthesis rates (Fv/Fm), and electron transport rates (ETRs) that were increased by 40%, 63–173%, and 50–78%, respectively, compared with those of plants without Mo–S crystals. Increased compatible osmolyte levels and decreased levels of oxidative damage, stomatal conductance (0.63–0.42 mmol m2 s–1), and transpiration (22.9–15.3 mmol m2 s–1), free radical scavenging, and calcium-dependent protein kinase, and Ca2+ signaling pathway activation were evidenced by transcriptomics and metabolomics. The bioself-assembled crystals originating from ions provide a method for protecting plant development under adverse conditions.