To elucidate nutritional components in sweet potato cultivars for table use and to compare the phytochemicals of cultivars from different countries, ‘Kokei No. 14′ and ‘Xinxiang’ were selected. The physiological parameters and metabolites were determined using the colorimetric method and widely targeted metabolomics, respectively. Transcriptomic analysis was performed to explain the mechanism that resulted in phytochemical differences. ‘Xinxiang’ showed higher flavonoid and carotenoid contents. Metabolomics showed five upregulated flavonoids. Two essential amino acids (EAAs) and one conditionally essential amino acid (CEAA) were upregulated, whereas four EAAs and two CEAAs were downregulated. Unlike lipids, in which only one of thirty-nine was upregulated, nine of twenty-seven differentially accumulated phenolic acids were upregulated. Three of the eleven different alkaloids were upregulated. Similarly, eight organic acids were downregulated, with two upregulated. In addition, three of the seventeen different saccharides and alcohols were upregulated. In ‘other metabolites,’ unlike vitamin C, 6′-O-Glucosylaucubin and pantetheine were downregulated. The differentially accumulated metabolites were enriched to pathways of the biosynthesis of secondary metabolites, ABC transporters, and tyrosine metabolism, whereas the differentially expressed genes were mainly concentrated in the metabolic pathway, secondary metabolite biosynthesis, and transmembrane transport functions. These results will optimize the sweet potato market structure and enable a healthier diet for East Asian residents.

Sweetpotato (Ipomoea batatas (L.) Lam.), whose roots are rich in starch, is widely grown around the world and plays a prominent role in ensuring food security. At present, there are no reports on the genetic diversity of sweetpotato germplasm revealed by InDel markers. In this study, we developed a set of 30 InDel markers to evaluate the genetic diversity and relationships of 240 accessions, comprising 77 landraces, 80 introduced accessions, 82 improved varieties released in China, and a diploid wild relative Ipomoea trifida. A total of 94 reliable loci were obtained, with a mean of 3.13 loci per primer, and the PIC value ranged from 0.143 to 0.821. The whole population could be divided into three sub-populations according to a structure analysis based on the Bayesian model, which was consistent with the results of principal component analysis (PCA). A neighbor-joining tree was constructed based on Nei’s genetic distance ranging from 0 to 0.556 and discriminated the panel of the population into three main groups (Ⅰ, Ⅱ, Ⅲ). Group Ⅲ was further split into seven subgroups (ⅢA–ⅢG). The clustering pattern of the 240 accessions was unrelated to their geographic origins. Most of the accessions, whether landraces, improved varieties released in China or introduced germplasm, were mixed, which revealed the high level of genetic similarity among accessions from different regions. There was little difference in the level of genetic diversity between landraces and improved varieties, which was probably due to the exchange and utilization of accessions from different regions. More efforts should be made to collect and utilize sweetpotato germplasm resources and further broaden the genetic basis of sweetpotato cultivars.

The sweetpotato (Ipomoea batatas [L.] Lam) is a globally significant crop, valued for its nutritional and economic importance. The tuberous roots of the sweetpotato are rich in carotenoids, which contribute to their vibrant colors and health benefits. This study focuses on three elite fresh-consumption sweetpotato cultivars: “Kokei No. 14,” “Xinxiang,” and “Zheshu81” with distinct flesh colors. To elucidate the metabolic pathways and genetic mechanisms underlying carotenoid biosynthesis in the sweetpotato, 20 types of carotenoids were quantified using targeted metabolomic analyses, and the key genes involved in carotenoid synthesis were identified with transcriptomic analyses. The results revealed significant differences in carotenoid content and composition among the cultivars, with “Zheshu81” exhibiting the highest carotenoid levels. Weighted gene co-expression network analysis further highlighted key regulatory genes and transcription factors influencing carotenoid accumulation. This study identifies key transcriptional regulators associated with carotenoid accumulation, sheds light on sweetpotato carotenoid biosynthesis mechanisms, and lays a foundation for breeding to improve its nutritional quality and flesh color.

Leaf color mutants are valuable resources for studying photosynthesis, pigment metabolism, and gene regulatory networks in plants. In this study, a naturally occurring sweetpotato albino mutant exhibiting a stable white-leaf phenotype across developmental stages was identified and compared with its green-leaf wild type to elucidate the molecular mechanisms underlying albinism. The mutant showed a dramatic 98.8% reduction in total chlorophyll content and a markedly decreased Fv/Fm value (0.59), indicating severe impairment of PSII efficiency. Integrated transcriptomic analysis identified 3520 differentially expressed genes (DEGs), while metabolomic profiling revealed 270 differentially accumulated metabolites (DAMs). Genes involved in chlorophyll and carotenoid biosynthesis, chloroplast development, and photosynthetic electron transport were strongly repressed, including key regulators such as GLK1, PORA, and PORB. Metabolomic alterations were mainly enriched in flavonoids, phenylpropanoids, and amino acid-derived pathways, reflecting broad reprogramming of both primary and secondary metabolism. These changes were accompanied by severely disrupted chloroplast ultrastructure, suggesting a primary defect in plastid development. Collectively, the integrated multi-omics evidence provides a comprehensive understanding of the coordinated transcriptional and metabolic alterations driving the albino phenotype in sweetpotato and establishes this mutant as a potential model for studying the interplay between chloroplast biogenesis, photosynthesis, and secondary metabolism.

Sweetpotato (Ipomoea batatas (L.) Lam.) is an important multifunctional crop with great value in food supply, industrial processing and bioenergy utilization. Crude protein content (CPC) is a core target trait for sweetpotato quality breeding. To dissect the genetic basis of CPC and identify key candidate genes, we used an F₁ population of 212 individuals. CPC was measured by near-infrared reflectance spectroscopy (NIRS) in 2020 and 2021, and QTL mapping was performed using a high-density SNP genetic linkage map. Candidate genes were explored via a genome-wide association study (GWAS), multiple-database functional annotation, and quantitative real-time PCR (qPCR) validation. The results showed that: (1) CPC in the population exhibited a continuous normal distribution with high inter-year stability, and phenotypic variation was mainly controlled by genetic factors; (2) one stable minor-effect QTL for CPC, qCPC09-1, was mapped to Chr09: 7906895–8614924 bp, explaining 5.7% of phenotypic variation; (3) GWAS detected no significant SNP loci, suggesting that CPC is regulated by multiple minor-effect genes; (4) genes within the qCPC09-1 interval were significantly enriched in three protein synthesis-related KEGG pathways: ribosome, nitrogen metabolism and ubiquinone and other terpenoid–quinone biosynthesis; (5) qPCR verified that itf09g13420 and itf09g13230 were upregulated in the low-CPC parent Yushu 10 and negatively correlated with CPC, while itf09g13550 was upregulated in the high-CPC parent Xin 24 and positively correlated with CPC. These three genes exhibited expression patterns highly consistent with phenotypic differences. This study provides a theoretical basis and technical support for molecular marker-assisted breeding and elite germplasm innovation in sweetpotato.

Sweetpotato (Ipomoea batatas (L.) Lam.) is a vital global food crop whose production and geographical distribution are severely constrained by low-temperature stress. While WRKY transcription factors are known to regulate plant stress responses, their specific roles in sweetpotato cold tolerance remain largely unexplored. In this study, we conducted a genome-wide identification of the WRKY family in the hexaploid sweetpotato genome, identifying 476 IbWRKYs classified into three major groups and seven subgroups. Synteny analyses revealed that whole-genome duplication (WGD)/segmental duplication (SD) was the primary mode of gene duplication for this conserved family. To identify key cold-responsive regulators, we evaluated the cold tolerance phenotypes of 232 diverse accessions and performed comparative transcriptome profiling on representative cold-tolerant and cold sensitive cultivars. Integrated transcriptomic and co-expression network analyses highlighted IbWRKY460 as a leading cold-responsive candidate. Quantitative RT-PCR confirmed its cold-induced expression, the GFP fusion protein localized to the nucleus, and heterologous expression in yeast provided preliminary evidence of protective activity during low-temperature exposure. Together, these findings prioritize IbWRKY460 for in-planta functional validation and provide a genomic framework for investigating cold-responsive WRKY genes in sweetpotato.