Unraveling Metabolic and Proteomic Features in Soybean Plants in Response to Copper Hydroxide Nanowires Compared to a Commercial Fertilizer

Mechanistic understanding of the
interaction of copper-based nanomaterials
with crops is crucial for exploring their application in precision
agriculture and their implications on plant health. We investigated
the biological response of soybean (Glycine max) plants to the foliar application of copper hydroxide nanowires
(CNWs) at realistic exposure concentrations. A commercial copper based-fungicide
(Kocide), dissolved copper ions, and untreated controls were used
for comparison to identify unique features at physiological, cellular,
and molecular levels. After 32 d of exposure to CNW (0.36, 1.8, and
9 mg CNW/plant), the newly developed tissues accumulated significantly
high levels of Cu (18–60 μg/g) compared to Kocide (10
μg/g); however, the rate of Cu translocation from the site of
CNW treatment to other tissues was slower compared to other Cu treatments.
Like Kocide, CNW exposure at medium and high doses altered Co, Mn,
Zn, and Fe accumulation in the tissues and enhanced photosynthetic
activities. The proteomic and metabolomic analyses of leaves from
CNW-treated soybean plants suggest a dose-dependent response, resulting
in the activation of major biological processes, including photosynthesis,
energy production, fatty acid metabolism, lignin biosynthesis, and
carbohydrate metabolism. In contrast to CNW treatments, Kocide exposure
resulted in increased oxidative stress response and amino acid metabolism
activation.