Differential Gene Expression and Metabolic Pathway Analysis of Cladophora rupestris under Pb Stress Conditions

This study aimed to analyze the transcriptome of C. rupestris under Pb²⁺ stress by using high-throughput sequencing technology, observe the changes of gene expression and metabolic pathway after three and five days under 1.0 and 5.0 mg/L of Pb²⁺ treatment, and analyze the differentially expressed genes (DEGs) and related functional genes after Pb²⁺ treatment. Metabolic pathways were revealed through Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Results show that DEGs increased significantly with the increase of Pb²⁺ concentration and stress time. A total of 32 genes were closely related to Pb²⁺ stress response. GO analysis identified two major transporter proteins, namely, ATP-binding transport protein-related (ABC transporters) and zinc finger CCHC domain containing protein (Zfp) in C. rupestris. Pthr19248, pthr19211, Zfp pthr23002, Zfp p48znf pthr12681, Zfp 294 pthr12389, and Zfp pthr23067 played important roles against Pb²⁺ toxicity and its absorption in C. rupestris. KEGG pathway analysis suggested that ABCA1, ATM, and ABCD3 were closely related to Pb²⁺ absorption. Pb²⁺ stress was mainly involved in metallothionein (MT), plant hormone signal transduction, ABC transporters, and glutathione (GSH) metabolism.