# Molecular Hydrogen Improves Blueberry Main Fruit Traits via Metabolic Reprogramming

## TL;DR

Molecular hydrogen irrigation improves blueberry fruit size and quality by altering metabolic processes.

## Contribution

This study identifies specific proteins and metabolic pathways influenced by hydrogen irrigation in blueberries.

## Key findings

- Hydrogen irrigation increased fruit weight and size in blueberries.
- Hydrogen improved fruit quality through changes in volatile compounds and antioxidant capacity.
- Specific enzymes and proteins were linked to hydrogen-induced metabolic changes.

## Abstract

Fruit yield and quality improvement are challenges for researchers and farmers. This study reveals that the main fruit traits of blueberry (Vaccinium ashei ‘Bluegem’) were significantly improved after hydrogen (H2)-based irrigation, assessed by the increased single fruit weight (14.59 ± 6.66%) and fruit equatorial diameter (4.19 ± 2.39%), decreased titratable acidity, increased solid–acid and sugar–acid ratios. The enhancement of fruit quality was confirmed by the increased total volatiles, vitamin C contents, and antioxidant capacity. Using weighted protein co-expression network analysis (WPCNA), proteomic interrogation revealed that serine carboxypeptidase-like proteins I/II (SCPLI/II), ADP ribosylation factor 1/2 (ARF1/2), and UDP-glucosyltransferase 85A (UGT85A) might be functionally associated with the increased fruit weight and size driven by H2. Reduced organic acid accumulation was caused by the regulation of the specific enzymes involved in sucrose metabolism (e.g., α-amylase, endoglucanase, β-glucosidase, etc.). H2 regulation of fatty acid degradation (e.g., acyl CoA oxidase 1 (ACX1), acetyl CoA acyltransferase 1 (ACAA1), etc.) and phenylpropanoid metabolism were used to explain the improved fruit aroma and anthocyanin accumulation. Meanwhile, the upregulated heat shock protein 20/70 matched with the enhanced antioxidant activity. Together, this study provides a novel approach for yield and quality improvement in horticultural crops.