Metabolomic analysis on the mechanism of nanoselenium alleviating cadmium stress and improving the chili pepper nutritional value

Abstract

Selenium (Se) can maintain rhizosphere soil-plant homeostasis and regulate signaling molecules to mitigate cadmium (Cd) toxicity. However, no systematic studies on the intervention of nano-selenium (nano-Se) in regulating non-target metabolites and fruit nutritional components in pepper plants under Cd stress were investigated. This study researched the effects of Cd-contaminated soil stress and nano-Se (1, 5, and 20mg/L) on the metabolic mechanism, fruit nutritional quality, and volatile organic compounds (VOCs) composition of pepper plants. The screening of differential metabolites in roots and fruits involved mostly amino acid metabolic pathways and capsaicin production pathways. Amino acid in roots (Pro, Trp, Arg, and Gln) and fruits (Phe, Glu, Pro, Arg, Trp, and Gln) were dramatically elevated by nano-Se biofortification. The expression of phenylpropane-branched fatty acid pathway genes (BCAT, Fat, AT3, HCT,and Kas) was induced by nano-Se (5 mg/L), which increased capsaicin (29.6%), nordihydrocapsaicin (44.2%), and dihydrocapsaicin (45.3%) levels. VOCs (amyl alcohol, linalool oxide, E-2-heptaldehyde, 2-hexenal, ethyl crotonate, and 2-butanone) related to crop resistance and quality were enhanced remarkably with the enhancement of nano-Se concentration. Therefore, nano-Se can improve the health of pepper plants by stimulating the expression of the capsaicin metabolic pathway and modulating the amino acid and VOCs contents.

Review on Pesticide Abiotic Stress over Crop Health and Intervention by Various Biostimulants

“…Additionally, Nano-Se can increase pepper's resistance to cadmium stress and lessen the harm caused by cadmium stress. 193 Kang 21 et al found that the mesophyll cells of melon leaves had fewer plastids, a maintained thylakoid membrane, more starch granules, and thickened cell walls in their examination of the effects of applying Nano-Se to several melon varieties. The Nano-Se treatment increased cucurbitacin B related synthesis gene expression as well as the antioxidant activity of the enzymes ascorbate peroxidase, peroxidase, phenylalanine ammonialyase, −1,3-glucanase, and Chitinase.…”