Comparative transcriptome analysis reveals the responses of sweetpotato to continuous cropping stress

Continuous cropping obstacles (CCO) severely limit the sustainable development of sweetpotato (Ipomoea batatas (L.) Lam.) industry. However, the transcriptional regulatory network of sweetpotato in response to continuous cropping stress (CCS) is unreported. Accordingly, transcriptome sequencing was employed to elucidate this network in two cultivars (Shangshu19 and Yizi138).

CCS markedly inhibited the growth of Yizi138, while its inhibition on Shangshu19 was relatively minor. Additionally, significantly more differentially expressed genes (DEGs) were detected in Shangshu19 compared with Yizi138. Metabolic pathways, plant hormone signal transduction, and the MAPK signaling pathway exert crucial functions in defending Shangshu19 against CCS. Weighted gene co-expression network analysis (WGCNA) demonstrated that multiple genes in the MEdarkred module, such as IbPR1, IbWRKY70, and IbCRK10, exhibited a positive correlation with continuous cropping tolerance, suggesting that these genes may be critically involved in boosting sweetpotato tolerance to continuous cropping. In contrast, continuous cropping impaired the photosynthetic system and energy metabolism in Yizi138, inhibiting its growth.

Shangshu19 enhances its tolerance to CCS via three strategies: regulation of key pathways, maintenance of physiological functions, and construction of a coordinated regulatory network mediated by IbPR1, IbWRKY70, and IbCRK10. These findings provide a theoretical foundation and genetic resources for breeding continuous cropping tolerance sweetpotato cultivars.