Differential expression pattern of novel MADS-box genes in early root formation and differentiation of sweet potato.

MADS-box genes are important transcription factors affecting overall development, but their role in sweet potato [Ipomoea batatas (L.) Lam.] has not been fully studied. This study isolated six novel MADS-box genes (IbSOC1, IbFUL1, IbAGL6, IbSVP1, IbSVP2, and IbSVP3) from sweet potato [Ipomoea batatas (L.) Lam. cv. Annouimo] during the early root differentiation stage using the de novo transcriptome assembly sequencing method. At the early root differentiation (between 0 and 3 days after transplanting), the IbSOC1, IbFUL1, and IbSVP2 genes decreased rapidly, whereas the IbSVP3 gene decreased gradually. In the early stages of root formation (0-30 days), the levels of IbSVP1 and IbSVP3 expression were steady, but the levels of IbSOC1 expression decreased gradually. The expression of six novel genes was also conducted in the tuberous root formation stage (30-90 days), and the IbSVP3 gene increased significantly according to the formation of the tuberous root. Six novel MADS-box genes that were believed to influence the entire root formation of sweet potato were isolated from the sweet potato. This study provides a genetic basis for further research on sweet potato root formation and development.