Functional identification of mango MiGID1A and MiGID1B genes confers early flowering and stress tolerance

The GIBBERELLIN INSENSITIVE DWARF1 (GID1) gene encodes a receptor integral to Gibberellic acid (GA) signaling, which is pivotal for plant growth, development, and stress responses. Until now, GID1 genes have not been documented in mango. In this research, the mango (Mangifera indica) genome yielded four GID1 homologous genes, and this study focuses on the research of MiGID1A and MiGID1B genes. Expression analysis indicated that MiGID1A is mainly expressed in leaves, while MiGID1B is predominantly found in flowers and buds. Both genes exhibited a significant upsurge in expression under salt and drought stress conditions. Moreover, the overexpression of these genes significantly advanced early flowering under long-day conditions. MiGID1A and MiGID1B transgenic plants showed significantly higher root length and survival rate than WT plants under drought and salt stress treatment. In addition, under drought and salt stress treatment, the contents of malonaldehyde (MAD) and hydrogen peroxide (H₂O₂) decreased significantly, and the levels of proline (Pro) and superoxide dismutase (SOD) notably increased in the MiGID1A-OE and MiGID1B-OE transgenic plants. GA₃ treatment significantly improved germination rates, root elongation, and early flowering in both MiGID1A-OE and MiGID1B-OE lines. At the same time, ABA treatment alleviated the inhibition of seed germination, root growth, and flowering in transgenic Arabidopsis. Moreover, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays demonstrated that MiGID1A and MiGID1B were capable of interacting with DELLA family proteins. Existing reports have demonstrated that GID1 participates in various regulatory processes by promoting the degradation of DELLA proteins. SQUAMOSA promoter binding protein-like (SPL3a/b) and WRKY12a/b. The findings imply a significant regulatory function for the MiGID1A and MiGID1B genes in the processes of flowering, stress management, and gibberellin response. KEY MESSAGE: MiGID1 as a GA receptor plays a critical role in the function of hormones, stress response, and promoting plant flowering.