Sweetpotato (Ipomoea batatas (L.) Lam.) is the seventh most important crop in the world and is mainly cultivated for its underground storage root (SR). The genetic studies of this species have been hindered by a lack of high-quality reference sequence due to its complex genome structure. Diploid Ipomoea trifida is the closest relative and putative progenitor of sweetpotato, which is considered a model species for sweetpotato, including genetic, cytological, and physiological analyses. Here, we generated the chromosome-scale genome sequence of SR-forming diploid I. trifida var. Y22 with high heterozygosity (2.20%). Although the chromosome-based synteny analysis revealed that the I. trifida shared conserved karyotype with Ipomoea nil after the separation, I. trifida had a much smaller genome than I. nil due to more efficient eliminations of LTR-retrotransposons and lack of species-specific amplification bursts of LTR-RTs. A comparison with four non-SR-forming species showed that the evolution of the beta-amylase gene family may be related to SR formation. We further investigated the relationship of the key gene BMY11 (with identity 47.12% to beta-amylase 1) with this important agronomic trait by both gene expression profiling and quantitative trait locus (QTL) mapping. And combining SR morphology and structure, gene expression profiling and qPCR results, we deduced that the products of the activity of BMY11 in splitting starch granules and be recycled to synthesize larger granules, contributing to starch accumulation and SR swelling. Moreover, we found the expression pattern of BMY11, sporamin proteins and the key genes involved in carbohydrate metabolism and stele lignification were similar to that of sweetpotato during the SR development. We constructed the high-quality genome reference of the highly heterozygous I. trifida through a combined approach and this genome enables a better resolution of the genomics feature and genome evolutions of this species. Sweetpotato SR development genes can be identified in I. trifida and these genes perform similar functions and patterns, showed that the diploid I. trifida var. Y22 with typical SR could be considered an ideal model for the studies of sweetpotato SR development.

Postharvest disease is an important limiting factor for sweetpotato production. Recently, a new green mold disease was found in sweetpotato storage roots. To investigate the mechanism underlying the pathogenesis of the disease, the pathogen was isolated and identified based on morphological and molecular features, and its characteristics were further analyzed by pathogenic and antagonistic evaluations. The results showed that the isolated pathogen (CRI-Ta1) was identified as Trichoderma asperellum based on the similar growth and morphological features with Trichoderma spp., 99% homology of internal transcribed spacer (ITS) sequence, and membership to the same phylogenetic group with the model strain of T. asperellum (CBS 433.97). The pathogenic analysis revealed that CRI-Ta1 could cause green mold disease through wound infection on the storage roots and the strains reisolated from infected storage roots could cause disease in different sweetpotato varieties, which was fulfilled in Koch’s postulate. Moreover, CRI-Ta1 could also infect other common crop species, including chestnut, carrot, apple, pear, and others. It indicated that CRI-Ta1 was the pathogen to the storage roots of sweetpotato and had a wide host range. Additionally, in vitro antagonistic evaluation showed that CRI-Ta1 effectively inhibited the growth of common sweetpotato pathogens, including Fusarium solani and Rhizopus nigricans. However, further research is needed on the potential of CRI-Ta1 to control sweetpotato diseases in vivo. Collectively, our findings provided valuable insights into the characteristics of the T. asperellum CRI-Ta1 in sweetpotato and would be helpful to the prevention and control of sweetpotato green mold disease.

This study investigates the early detection of sweet potato scab by using hyperspectral imaging and machine learning techniques. The research focuses on developing an accurate, economical, and non-destructive approach for disease detection and grading. Hyperspectral imaging experiments were conducted on two sweet potato varieties: Guangshu 87 (resistant) and Guicaishu 2 (susceptible). Data preprocessing included denoising, region of interest (ROI) selection, and average spectrum extraction, followed by dimensionality reduction using principal component analysis (PCA) and random forest (RF) feature selection. A novel dynamic grading method based on spectral-time data was introduced to classify the early stages of the disease, including the early latent and early mild periods. This method identified significant temporal spectral changes, enabling a refined disease staging framework. Key wavebands associated with sweet potato scab were identified in the near-infrared range, including 801.8 nm, 769.8 nm, 898.5 nm, 796.4 nm, and 780.5 nm. Classification models, including K-nearest neighbor (KNN), support vector machine (SVM), and linear discriminant analysis (LDA), were constructed to evaluate the effectiveness of spectral features. Among these classification models, the MSC-PCA-SVM model demonstrated the best performance. Specifically, the Susceptible Variety Disease Classification Model achieved an overall accuracy (OA) of 98.65%, while the Combined Variety Disease Classification Model reached an OA of 95.38%. The results highlight the potential of hyperspectral imaging for early disease detection, particularly for non-destructive monitoring of resistant and susceptible sweet potato varieties. This study provides a practical method for early disease classification of sweet potato scab, and future research could focus on real-time disease monitoring to enhance sweet potato crop management.

Phosphorus deficiency poses a significant challenge to the growth and productivity of crops, particularly in nutrient-poor soils. This study investigates the effects of phosphorus deficiency on the growth, endogenous phytohormones, metabolome, and transcriptome of sweet potato (Ipomoea batatas L.) over a growth period from 30 to 120 days. We found that low phosphorus conditions significantly reduced both above- and below-ground biomass, while tuber number remained unchanged. Endogenous phytohormone analysis revealed altered levels of abscisic acid (ABA), indole-3-acetic acid (IAA), and cytokinins, indicating a complex hormonal response to phosphorus starvation. Transcriptomic analysis identified a total of 6324 differentially expressed genes (DEGs) at 60 days, with significant enrichment in pathways related to stress response and phosphorus utilization (PAPs and PHO1). Metabolomic profiling revealed notable shifts in key metabolites, with consistent downregulation of several phosphorous-related compounds. Our findings highlight the intricate interplay between growth, hormonal regulation, metabolic reprogramming, and gene expression in response to phosphorus deficiency in sweet potato. This research underscores the importance of understanding nutrient stress responses to enhance sweet potato resilience and inform sustainable agricultural practices. Future research should focus on exploring the potential for genetic and agronomic interventions to mitigate the effects of phosphorus deficiency and optimize sweet potato productivity in challenging environments.

Dry rot caused by Diaporthe batatatis leads to the serious decay of sweetpotato storage roots during postharvest storage, which can result in considerable economic loss. Genomic research of the pathogen could provide a basis for study and prevention of sweetpotato dry rot. Herein, we report a high-quality draft genome sequence of D. batatatis CRI 302-4 isolated from infected sweetpotato storage roots in Taizhou City, Zhejiang Province, China. The size of the genome was 54.38 Mb and consisted of 36 scaffolds with a G+C content of 50.56% and an N₅₀ of 2,950,914 bp. The information provided in this genome sequence will be an invaluable resource for molecular genetic research and disease control in sweetpotato production.