RNA sequencing-based transcriptomic characterization of the regulation of flowering in sweet potato cultivars Ipomoea batatas L. (Shinyulmi vs. Morning purple)

Extensive studies on organ development in model plants, such as Arabidopsis and rice, along with the identification of various functional genes, have improved the understanding and characterization of agriculturally important traits in major crops. In sweet potato, a vegetatively propagated crop, the underground tuberous root, constitutes a critical organ, and substantial efforts have been made to elucidate its formation and development mechanisms. Despite this, comprehensive comparative analyses remain limited, both in terms of the regulatory mechanisms underlying the transition from vegetative to reproductive growth and in the identification and functional characterization of the key genes involved in flowering. This study identified the core genes involved in flowering induction and the formation of tuberous roots in ‘Morning Purple’ and ‘Shinyulmi’ sweet potato cultivars, which exhibit distinct aboveground and underground phenotypic traits. The genes differentially expressed between the two cultivars are associated with the MADS-box, MYB, and AP2 transcription factors, which play pivotal roles in plant growth and development processes. Among the differentially expressed genes, approximately 11.75% of the total genes were identified as candidate genes involved in the phenotypic differences between the two cultivars. AGL15;2 and AGL71 exhibited distinct cultivar-specific expression patterns in ‘Shinyulmi’ and ‘Morning Purple,’ respectively, implicating their roles in phenotypic differentiation and the transition to reproductive growth. These findings highlight the key regulatory genes uniquely expressed in each cultivar, suggesting potential targets for further functional characterization. This study will enable its utilization in molecular breeding and contribute to agricultural development, including the augmentation of crop yields, through research on crops that utilize vegetative reproduction organs.