Comparative metabolomic analyses reveal metabolites associated with seed deterioration in Chinese cabbage

Abstract

Seed deterioration during storage results in a decline in vigor, which has a negative impact on agricultural production. However, the mechanisms responsible for ageing are still poorly understood. The aim of present study was to investigate the physiological, biochemical, and metabonomic changes in naturally aged Chinese cabbage (Brassica pekinensis L.) seeds, and identify potential markers of seed deterioration. In this study, Chinese cabbage seeds with different moisture contents (1 % and 4 %) were stored under ambient conditions for 13 years. We employed a biochemical and metabolomics approach to investigate the impact of seed deterioration on naturally aged Chinese cabbage seeds and to identify the types and variations of differentially accumulated metabolites. Our findings demonstrate that the initial storage moisture content has a significant impact on the loss of seed vigor. The seed lot with an initial moisture content of 1 % exhibited higher viability and vigor after natural storage. High-vigor seeds showed higher catalase (CAT) activity, lower H2O2 and malondialdehyde (MDA) content, and reduced electrolyte leakage. No significant difference was observed between the two seed lots in terms of superoxide dismutase (SOD) activity, peroxidase (POD) activity, and soluble protein content. Metabolite analysis revealed 1,117 differential metabolites between the two seed lots. The differential metabolites were associated with various aspects of seed ageing, including changes in glycerophospholipids, phytohormones, antibiotics, reduction of antioxidant substances and raffinose, degradation of triglycerides, accumulation of toxic compounds, and DNA damage. Longicamphenylone was the prominent metabolite in response to seed deterioration. Pathway enrichment analysis revealed that flavonoid biosynthesis, which is involved in scavenging reactive oxygen species(ROS), was the most significant metabolic pathway associated with seed deterioration. Our findings also present the initial evidence linking endogenous antibiotics with seed aging.