LAUSR

Simple Summary The present study initially identified four full-length genes (peroxidase1, AmPRX1; peroxidase2 AmPRX2; pectate lyase, AmPL; phytosulfokine, AmPSK) associated with metal tolerance in Avicennia marina, one of the pioneer mangrove species with adaptive features. These genes showed the characteristic features of the respective protein families, indicating their evolutionarily conserved relationship with other plant proteins (e.g., CrPRX in Catharanthus roseus, MtPRX in Medicago truncatula, and NnPSK in Nelumbo nucifera). Real-time quantitative PCR revealed that AmPRX1, AmPRX2, and AmPL were most abundantly expressed in the leaves, while AmPSK displayed similar transcript levels across leaves, stems, and roots. Additionally, increased expression levels of these genes were detected in A. marina leaves under cadmium stress. The study thus suggests the role of these four genes in the cadmium stress response and provides a basis for detailed functional studies. Abstract Mangroves colonize the intertidal area of estuaries (e.g., Pichavaram, Payardia, and Mai Po) with remarkable cadmium (Cd) pollution. A study on the mechanism of mangrove plant response to Cd pollution can help to understand the adaptive characteristics of plants under Cd stress. This study explored the roles of peroxidase (PRX), pectate lyase (PL), and phytosulfokine (PSK) genes in cadmium tolerance of mangrove Avicennia marina. Full-length sequences of four genes (i.e., AmPRX1, AmPRX2, AmPL, and AmPSK) associated with metal tolerance were identified with suppression subtractive hybridization and rapid amplification of cDNA ends. These genes showed the characteristic features of the respective protein family, indicating functions similar to other plant proteins. Real-time quantitative PCR analysis demonstrated that cadmium exposure resulted in differences in expression patterns among the tissues. Our findings emphasize the complex regulatory mechanism of these four genes in response to trace metal pollution and reveal their functions in metabolic signaling during the stress response.