ScholarWorks@경상국립대학교

초록

Environmental stress caused by biotic and abiotic factors negatively affects crop quality and productivity. Plants employ multiple signaling mechanisms under stress, with the mitogen-activated protein kinase (MAPK) cascade-particularly MPK3 and MPK6-serving as a central regulator of stress adaptation through substrate phosphorylation. While these kinases are well-studied in model plants, their functional role in sweet potato [Ipomoea batatas (L.) Lam] remains poorly characterized. This study investigates how cold tolerance in sweet potato is modulated by IbMPK3/IbMPK6-mediated phosphorylation of the stress-responsive transcription factor IbSPF1 at Ser75 and Ser110. Wild-type and transgenic sweet potato plants were grown under normal and cold-stress conditions, followed by the assessment of IbSPF1 phosphorylation levels and plant physiological parameters. Notably, transgenic plants overexpressing IbSPF1 (IbSPF1DD) exhibited significantly higher tolerance to cold stress than non-transgenic plants under cold stress condition, which was attributed to an increase in photosynthetic efficiency and a decrease in lipid peroxidation. Compared with non-transgenic plants, transgenic IbSPF1DD plants showed significantly upregulated levels of cold-regulated genes. Conclusively, IbMPK3/IbMPK6-mediated phosphorylation of IbSPF1 plays an important role in cold stress signaling and tolerance in sweet potato. © 2025 Elsevier Inc.

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