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Diurnal light-dark cycles regulate nutrient uptake and transport; however, the underlying molecular mechanisms remain largely unknown. Transcription factor MYB59 and ion transporter NPF7.3 participate in root-to-shoot K + /NO 3 - translocation in Arabidopsis. In this study, transcriptional analyses and western blotting experiments revealed the diurnal expression of the MYB59-NPF7.3 module. ChIP-qPCR and EMSA showed that transcription factors HY5 and PIF directly bind to the MYB59 promoter. Phenotype analyses and ion content measurement indicated that HY5 and PIF antagonistically control root-to-shoot K + /NO 3 - translocation through the MYB59-NPF7.3 module. We found HY5 proteins accumulate in roots and repress MYB59 transcription during daytime, while PIF proteins promote MYB59 transcription in the dark. The expression levels of the NPF7.3 transcript and protein are gradually decreased during daytime, but increased at night. The enhancement of K + /NO 3 - loading into the xylem mediated by NPF7.3 could increase root pressure at night, which maintained the root-to-shoot water/nutrient translocation. This study reveals a synergistic mechanism between light signaling and nutrient transport in plants, and defines a diurnal molecular switch of driving forces for root-to-shoot water/nutrient translocation., (© 2025 The Author(s). New Phytologist © 2025 New Phytologist Foundation.)

Chloride (Cl - ) ions cause major damage to crops in saline soils. Understanding the key factors that influence Cl - uptake and translocation will aid the breeding of more salt-tolerant crops. Here, using genome-wide association study and transcriptomic analysis, we identified a NITRATE TRANSPORTER 1 (NRT1)/PEPTIDE TRANSPORTER family (NPF) protein, GmNPF7.5, as the dominant gene locus influencing Cl - homeostasis in soybean (Glycine max). A natural SNP variation resulted in two haplotypes (GmNPF7.5 HapA and GmNPF7.5 HapB ), which was associated with Cl - content. GmNPF7.5 HapA mediated Cl - or nitrate (NO 3 - ) uptake in a pH-dependent manner and exhibited higher permeability for Cl - over NO 3 - . The suppression of GmNPF7.5 HapA expression decreased Cl - accumulation and salt damage in plants, whereas its overexpression showed the opposite effects. The elite haplotype GmNPF7.5 HapB diminished Cl - transport activity independently from NO 3 - permeability, thus enhancing soybean salt tolerance. Furthermore, the protein kinase GmPI4Kγ4 could phosphorylate GmNPF7.5, which repressed Cl - uptake without affecting NO 3 - permeability. Our findings define a regulatory mechanism for Cl - control under NaCl stress, providing a strategy for the improvement of salt tolerance in soybean plants., Competing Interests: Disclosure and competing interests statement. The authors declare no competing interests., (© 2025. The Author(s).)

Systemic signaling is an essential hallmark of multicellular life. Pathogen encounter occurs locally but triggers organ-scale and organismic immune responses. In plants, elicitor perception provokes systemically expanding Ca 2+ and H 2 O 2 signals conferring immunity. Here, we identify a Ca 2+ sensing bi-kinase module as becoming super-activated through mutual phosphorylation and as imposing synergistically enhanced NADPH oxidase activation. A combined two-layer bi-kinase/substrate phospho-code allows for sensitized signaling initiation already by near-resting elevations of Ca 2+ concentration. Subsequently, it facilitates further signal wave proliferation with minimal Ca 2+ amplitude requirement, triggering protective defense responses throughout the plant. Our study reveals how plants build and perpetuate trans-cellular immune signal proliferation while avoiding disturbance of ongoing cellular signaling along the path of response dissemination.