Molecular characterization of nine sweet potato (Ipomoea batatas Lam.) MADS-box transcription factors during storage root development and following abiotic stress

Sweet potato is an important plant for researchers to study storage root development and resistance. MADS-box proteins are a group of important transcription factors which play a crucial role in plant development as well as stress response. However, the investigation regarding sweet potato MADS-box genes remains limited up to now. In this study, nine MADS-box genes, named as IbMBP1-IbMBP9, were cloned and characterized. Nine genes exhibited different tissue-specific expression profiles. IbMBP2, IbMBP3, IbMBP4 and IbMBP9 showed high expression during storage roots development and were upregulated by storage roots development-related hormones. Varying degrees of induction was observed in the transcript level of these MADS-box genes under multiple abiotic stresses, as well as stress-related hormones. The present results revealed that nine MADS-box genes exhibited different tissue-specific expression profiles and were impacted by multiple abiotic stresses and/or hormones, which lay a good foundation for further exploring the function of MADS-box genes in sweet potato.