Study on the Mechanism of Trimetazidine Hydrochloride Alleviating Waterlogging Stress in Rapeseed (Brassica napus L.)

Waterlogging damage has seriously affected the growth and development of rapeseed, which has become a major problem in rapeseed production. Trimetazidine hydrochloride (TMZ) is a metabolic agent that can inhibit fatty acid oxidation and promote sugar oxidation. In order to study the effect of TMZ on the waterlogging tolerance of rapeseed, this study selected the waterlogging-sensitive Brassica napus inbred line YZ59 as the experimental material, and studied the effects of different concentrations of TMZ treatment on the phenotype, physiology, and gene transcription of waterlogged rapeseed at the germination stage and four-leaf stage. The results showed that 200 mg L^-1 TMZ treatment significantly alleviated the growth inhibition of rapeseed at the germination stage and increased the seedling rate by 92.5%. Compared with waterlogged rapeseed, after 4 days of 80 mg L^-1 TMZ treatment, the superoxide dismutase (SOD) activity, catalase (CAT) activity, free proline (Pro) content, and relative conductivity of waterlogged rapeseed at the four-leaf stage increased by 18.1%, 20.8%, 142.2%, and 11.5%, respectively. Lipoxygenase (LOX) activity and malondialdehyde (MDA) content decreased by 27.9% and 22.6%, respectively. Transcriptome sequencing results showed that, compared with waterlogged rapeseed, TMZ treatment could induce the differential expression of key genes in various waterlogging-related pathways in waterlogged rapeseed. Comprehensive analysis showed that TMZ could improve waterlogging tolerance of rapeseed by promoting antioxidant defense and osmotic adjustment, inhibiting fatty acid oxidation, accelerating glycolysis, and promoting photosynthesis efficiency. Various hormones, such as ethylene (ET), abscisic acid (ABA), jasmonic acid (JA), and brassinosteroid (BRs), could regulate this process through mutual synergy or antagonism.