Strawberry Yield Improvement by Hydrogen-Based Irrigation Is Functionally Linked to Altered Rhizosphere Microbial Communities.

Molecular hydrogen (H2) is crucial for agricultural microbial systems. However, the mechanisms underlying its influence on crop yields is yet to be fully elucidated. This study observed that H2-based irrigation significantly increased strawberry (Fragaria × ananassa Duch.) yield with/without nutrient fertilization. The reduction in soil available nitrogen (N), phosphorus (P), potassium (K), and organic matter was consistent with the increased expression levels of N/P/K-absorption-related genes in root tissues at the fruiting stage. Metagenomics profiling showed the alterations in rhizosphere microbial community composition achieved by H2, particularly under the conditions without fertilizers. These included the enrichment of plant-growth-promoting rhizobacteria, such as Burkholderia, Pseudomonas, and Cupriavidus genera. Rhizobacteria with the capability to oxidize H2 (group 2a [NiFe] hydrogenase) were also enriched. Consistently, genes related to soil carbon (C) fixation (i.e., rbcL, porD, frdAB, etc.), dissimilar nitrate reduction (i.e., napAB and nrfAH), and P solublization, mineralization, and transportation (i.e., ppx-gppA, appA, and ugpABCE) exhibited higher abundance. Contrary tendencies were observed in the soil C degradation and N denitrification genes. Together, these results clearly indicate that microbe-mediated soil C, N, and P cycles might be functionally altered by H2, thus increasing plant nutrient uptake capacity and horticultural crop yield.

The delayed senescence in harvested blueberry by hydrogen-based irrigation is functionally linked to metabolic reprogramming and antioxidant machinery.

Molecular hydrogen is beneficial for fruits quality improvement. However, the mechanism involved, especially cellular metabolic responses, has not been well established. Here, the integrated widely targeted metabolomics analysis (UPLC-MS/MS) and biochemical evidence revealed that hydrogen-based irrigation could orchestrate, either directly or indirectly, an array of physiological responses in blueberry (Vaccinium spp.) during harvesting stage, especially for the delayed senescence in harvested stage (4 °C for 12 d). The hubs to these changes are wide-ranging metabolic reprogramming and antioxidant machinery. A total of 1208 distinct annotated metabolites were identified, and the characterization of differential accumulated metabolites (DAMs) revealed that the reprogramming, particularly, involves phenolic acids and flavonoids accumulation. These changes were positively matched with the transcriptional profiles of representative genes for their synthesis during the growth stage. Together, our findings open a new window for development of hydrogen-based agriculture that increases the shelf-life of fruits in a smart and sustainable manner.