Transcriptome Analysis of Different Chinese Cabbage Varieties Under Cd and Pb Stresses.

In recent years, soil heavy metal pollution has become increasingly serious, particularly Cd and Pb pollution, and heavy metals have been accumulating in soil-crop systems, posing great risks to human health. In this study, four Chinese cabbage varieties with different Cd and Pb accumulation traits were cultivated using hydroponics and transcriptome sequencing technology to reveal the response mechanism of Chinese cabbage to Cd and Pb stress at the molecular level. The numbers of upregulated genes in Harmony Express (H) and Ziwei F1 (F) were 2904 and 3004, respectively, under Cd stress (0 mg/L vs. 80 mg/L), whereas the numbers of upregulated genes in Green Crown (L) and Suzhou Green (S) were 3424 and 2724, respectively, under Pb stress (0 mg/L vs. 1200 mg/L). GO enrichment analysis revealed that 52 functional subgroups were enriched in H0 vs. H80 and F0 vs. F80, and 79 functional subgroups were enriched in L0 vs. L1200 and S0 vs. S1200. KEGG enrichment indicated that secondary metabolite biosynthesis, metabolic pathways, and phenylpropanoid biosynthesis are important regulators of the response to Cd and Pb stress in Chinese cabbage. In addition, genes related to antioxidant enzymes (e.g., CAT and glutathione transferase), metal transporter proteins (e.g., ABC), mitogen-activated protein kinases, and calmodulin were significantly differentially expressed, suggesting that they are jointly involved in the detoxification of Chinese cabbage in response to heavy metal stress. In total, 881 and 858 differentially expressed genes (DEGs) in the transcription factor family responded to Cd and Pb stress, respectively. This study reveals the response mechanism of Chinese cabbage to Cd and Pb stress at the molecular level and provides a theoretical basis for the cultivation of low-Cd and low-Pb-enriched varieties and the mining of heavy metal tolerance genes.