Functional Characterization of Sugar Beet M14 Antioxidant Enzymes in Plant Salt Stress Tolerance

Salt stress can cause cellular dehydration, which induces oxidative stress by increasing the production of reactive oxygen species (ROS) in plants. They may play signaling roles and cause structural damages to the cells. To overcome the negative impacts, the plant ROS scavenging system plays a vital role in maintaining the cellular redox homeostasis. The special sugar beet apomictic monosomic additional M14 line (BvM14) showed strong salt stress tolerance. Comparative proteomics revealed that six antioxidant enzymes (glycolate oxidase (GOX), peroxiredoxin (PrxR), thioredoxin (Trx), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase3 (DHAR3)) in BvM14 were responsive to salt stress. In this work, the full-length cDNAs of genes encoding these enzymes in the redox system were cloned from the BvM14. Ectopic expression of the six genes reduced the oxidative damage of transgenic plants by regulating the contents of hydrogen peroxide (H2O2), malondialdehyde (MDA), ascorbic acid (AsA), and glutathione (GSH), and thus enhanced the tolerance of transgenic plants to salt stress. This work has charecterized the roles that the antioxidant enzymes play in the BvM14 response to salt stress and provided useful genetic resources for engineering and marker-based breeding of crops that are sensitive to salt stress.

Automated summary

Salt stress induces cellular dehydration and oxidative stress in plants through the production of reactive oxygen species (ROS). The plant ROS scavenging system, including antioxidant enzymes, is crucial for maintaining cellular redox homeostasis. A study on the salt-tolerant sugar beet apomictic monosomic additional M14 line (BvM14) revealed that six antioxidant enzymes were responsive to salt stress. Cloning and overexpression of these genes in transgenic plants improved salt stress tolerance by regulating the levels of H2O2, MDA, AsA, and GSH. This research provides insights into the roles of antioxidant enzymes in the response to salt stress and offers genetic resources for crop engineering and breeding.