Hydrogen peroxide promotes potassium uptake by activating flavonoid biosynthesis pathway and ethylene signaling in grapevines.

• Hydrogen peroxide (H 2 O 2) treatment improves K+ uptake in grapes. • H 2 O 2 treatment activates flavonoid biosynthesis pathway. • H 2 O 2 changes ethylene signaling to promote K+ uptake by regulating K+ transporters. Potassium ion (K+) is an essential nutrient for plants. Grapes are an important industrial crop with an extremely high demand for potassium. However, potassium deficiency occurs frequently in viticulture and greatly restricts the grape industry. Developing a technique to improve potassium uptake efficiency is of vital importance for grapes. In this study, we found that hydrogen peroxide (H 2 O 2) treatment could improve K+ uptake in grapes. To determine the mechanisms underlying H 2 O 2 -induced K+ uptake, transcriptome sequencing (RNA-seq) was conducted and the differentially expressed genes were further analyzed. Gene Ontology (GO) enrichment indicated that ion transport-related pathways and genes changed after H 2 O 2 treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and weighted gene co-expression network analysis (WGCNA) showed that the flavonoid biosynthesis pathway was closely related to H 2 O 2 -induced K+ uptake, and H 2 O 2 treatment could activate the flavonoid biosynthesis pathway. Further analysis demonstrated that H 2 O 2 treatment could activate ethylene synthesis and the ethylene signaling pathway, which promoted K+ uptake by regulating K+ transporter genes. Overall, this study demonstrates a new technique, H 2 O 2 treatment, for enhancing potassium uptake efficiency in grapes and reveals the molecular mechanisms underlying H 2 O 2 -induced K+ uptake. [ABSTRACT FROM AUTHOR]