Proteomic analysis of MsFtsH8 overexpression reveals enhanced salt stress response in alfalfa through PSII stability and antioxidant capacity improvement

The FtsH (Filamentous temperature sensitive H) proteases, known for their crucial roles in protein quality control and maintaining the integrity of photosynthetic machinery, have emerged as key regulators of stress responses in plants. Our previous study revealed the overexpression of MsFtsH8, an FtsH gene from alfalfa (Medicago sativa L.), confers salt stress tolerance to the plant. By comparing the proteomic profiles of MsFtsH8-overexpressing alfalfa and wild type under salt stress conditions, we elucidate the molecular pathways underlying MsFtsH8-mediated salt stress resilience. We identified 730 differentially expressed proteins (DEPs) in MsFtsH8-overexpressing alfalfa under salt stress, compared to 498 DEPs in wild type alfalfa under the same growth condition. Our results reveal significant alterations in the expression of proteins involved in the photosynthetic system, consistent with the chloroplast subcellular localization of MsFtsH8. Specifically, MsFtsH8 overexpression stabilizes key components of Photosystem II (PSII) and enhances electron transport processes, leading to increased photosynthetic efficiency and oxidative photodamage repair capacity under salt stress. Moreover, MsFtsH8-overexpressing alfalfa exhibits elevated levels of antioxidative enzymes, further mitigating oxidative damage induced by high salinity. These findings deepen our understanding of the regulatory role of MsFtsH8 in salt stress response and highlight its potential for improving crop resilience under adverse environmental conditions.