Sweetpotato sucrose transporter IbSUT1 alters storage roots formation by regulating sucrose transport and lignin biosynthesis

• Published in: The Plant journal : for cell and molecular biology 2024-11, Vol.120 (3), p.950-965
• Main Authors: Wang, Dandan, Li, Chengyang, Liu, Hongjuan, Song, Weihan, Shi, Chunyu, Li, Qiang
• Format: Article
• Language: English
• Subjects: Accumulation; Arabidopsis - genetics; Arabidopsis - metabolism; Biochemical analysis; Biological Transport; Biosynthesis; Crop yield; Deposition; Efflux; Gene expression; Gene Expression Regulation, Plant; IbSUT1; Ipomoea batatas; Ipomoea batatas - genetics; Ipomoea batatas - growth & development; Ipomoea batatas - metabolism; Lignin; Lignin - biosynthesis; Lignin - metabolism; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Phenotypes; Plant layout; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - genetics; Plant Roots - growth & development; Plant Roots - metabolism; Plants, Genetically Modified; Roots; Stems; storage root formation; Sucrose; Sucrose - metabolism; Sucrose transporter; Sweet potatoes; sweetpotato
• ISSN: 0960-7412; 1365-313X; 1365-313X
• DOI: 10.1111/tpj.17029

SUMMARY The formation and development of storage roots is the most important physiological process in sweetpotato production. Sucrose transporters (SUTs) regulate sucrose transport from source to sink organs and play important roles in growth and development of plants. However, whether SUTs involved in sweetpotato storage roots formation is so far unknown. In this study, we show that IbSUT1, a SUT, is localized to the plasma membrane. Overexpression of IbSUT1 in sweetpotato promotes the sucrose efflux rate from leaves, leading to increased sucrose levels in roots, thus induces lignin deposition in the stele, which inhibits the storage roots formation and compromises the yield. Heterologous expression of IbSUT1 in Arabidopsis significantly increases the sucrose accumulation and promotes lignification in the inflorescence stems. RNA‐seq and biochemical analysis further demonstrated that IbMYB1 negatively regulates the expression of IbSUT1. Overexpression of IbMYB1 in Arabidopsis reduces the sucrose accumulation and lignification degree in the inflorescence stems. Moreover, co‐overexpression of IbMYB1 and IbSUT1 restores the phenotype of lignin over‐deposition in Arabidopsis. Collectively, our results reveal that IbSUT1 regulates source‐sink sucrose transport and participates in the formation of sweetpotato storage roots and highlight the potential application of IbSUT1 in improving sweetpotato yield in the future. Significance Statement The formation and development of storage roots is the most important physiological process in sweetpotato production. IbSUT1 plays a crucial role in the formation of storage roots by regulating sucrose transport to affect lignin biosynthesis in roots, which provides valuable information for understanding the mechanisms underlying sweetpotato root development and may have implications for the improvement of sweetpotato yields.