Isolation and characterization of MADS box genes possibly related to root development in sweetpotato (Ipomoea batatas L. Lam.)

Development of the tuberous root of sweetpotato coincides with abnormal vascular cambium activity. The genes and pathways predominately active for vascular morphogenesis in sweetpotato root are unknown. In this study, using a reverse transcription-polymerase chain reaction (RT-PCR) approach, we found three sweetpotato MADS box genes expressed in root tissues. IbAGL17 is an AGL17 clade MADS box gene, and was mainly expressed in tuberous root as demonstrated by RT-PCR analysis. IbAGL20 is a TM3-like gene that is expressed at similar levels in leaf, vegetative shoot, flower and root tissues. IbMADS79 closely resembled the Arabidopsis AP1 and Antirrhinum SQUA genes, but IbMADS79 was expressed only in roots, whereas the mRNA levels of genes of SQUA clade were high in the flower and floral meristem. RT-PCR results confirmed that MADS box genes were also expressed in different developmental stages. These differentially expressed MADS box genes will be potential candidates for research to elucidate the molecular process related to root development in sweetpotato.