Shenglin Wang

Leaf color, as a key ornamental and quality trait in leafy vegetable sweet potato, is controlled by the coordinated regulation of multiple pigment metabolic pathways. To dissect the mechanisms underlying leaf color variation, the integrated transcriptomic and metabolomic analyses were performed on three contrasting phenotypes: green (G), yellow (Y), and purple-red (R). The results showed that purplish-red leaves accumulated the highest levels of anthocyanins (16.36 mg·g⁻¹) and total chlorophyll (2.54 mg·g⁻¹), indicating that the synergistic accumulation of anthocyanins and chlorophyll contributes to their dark pigmentation. In contrast, yellow leaves contained the lowest carotenoid content yet displayed the highest carotenoid-to-chlorophyll ratio (6.44), suggesting that reduced chlorophyll levels coupled with a relatively higher carotenoid proportion underlie the yellow phenotype. Green leaves exhibited a more balanced pigment profile, with a total chlorophyll content of 1.94 mg·g⁻¹. Transcriptomic profiling revealed elevated expression of anthocyanin biosynthetic genes CHS, CHI, F3H, and chlorophyll metabolism-related genes CHLG and CAO in purplish-red leaves, whereas carotenoid biosynthesis genes LCY and CYP97A3 showed specific regulation in yellow leaves. Collectively, these findings demonstrate that leaf color formation in leafy vegetable sweet potato is determined by the relative accumulation of chlorophylls, carotenoids, and anthocyanins, together with differential regulation of their biosynthetic pathways. This work provides novel insights into the molecular basis of leaf color variation and offers a theoretical foundation for genetic improvement of leafy vegetable sweet potato.

Objective This study aims to analyze the genetic diversity of Dioscorea alata L. resources in southern China，thus providing a theoretical basis for their innovative utilization and variety breeding. Method Twenty Dioscorea alata L. germplasm resources from southern China were subjected to biological identification and phenotypic diversity analysis.Principal component analysis and cluster analysis were conducted to systematically investigate the phenotypic differences and genetic variations among these resources. Result （1）The germplasm resources of the 20 samples exhibited abundant variations.The Shannon index for qualitative traits ranged from 0.325 to 1.280，with root hair distribution，tuber shape，and tuber color showing the highest diversity.The coefficient of variation for quantitative traits ranged from 11.96% to 163.80%，with tuber diameter exhibiting the highest variation（163.80%）and leaf SPAD value showing the lowest variation（11.96%）.（2）Cluster analysis based on phenotypic traits revealed that with an Euclidean distance of 20，the germplasm resources were divided into two clusters，with Lijiang Purple yam forming a seperate cluster.With an Euclidean distance of 15，the resources were further divided into five clusters. Conclusion Underground tuber traits are the primary factors influencing the diversity of Dioscorea alata L.，with tuber diameter contributing the most to phenotypic variation.Comprehensive evaluation shows that Lijiang Purple yam，Ganziyu No.3，and Ganbaiyu No.2 exhibited outstanding phenotypic traits，demonstrating significant potential for promotional application.

Taro (Colocasia esculenta (L.) Schott) is the fifth largest rhizome crop, and it is widely distributed in tropical and subtropical areas in the world. Vegetative propagation with virus-infected corms can lead to cultivar degradation, yield decline, and quality deterioration. In this study, the shoot apical meristems excised from taro corms infected with dasheen mosaic virus, which belongs to the genus Potyvirus in the family Potyviridae, were cultured and treated with exogenous abscisic acid and high sucrose concentrations to induce micro-corm formation. Subsequently, candidate genes involved in micro-corm expansion were screened via transcriptome sequencing analysis. The results revealed that the shoot apical meristems could grow into adventitious shoots on the medium 1 mg/L 6-benzylaminopurine + 0.3 mg/L 1-naphthaleneacetic acid, and reverse transcription–polymerase chain reaction detection indicated that dasheen mosaic virus had been successfully eliminated from the test-tube plantlets. Moreover, 8% sucrose or 3% sucrose + 5 μM abscisic acid likewise induced taro corm formation, and genes related to cell division and the cell cycle, as well as starch and sucrose metabolism pathways, were significantly enriched during taro corm expansion. Furthermore, the cyclin-dependent kinases genes, cell cycle protein kinase subunit genes, and cyclin B2 genes, which are related to cell division and the cell cycle, were upregulated with abscisic acid treatment on the 3rd day. The sucrose synthase genes, β-amylase genes, glycogen branching enzyme genes, and soluble starch synthase genes, which are related to starch and sucrose metabolism, were upregulated on the 15th day, indicating that cell division largely occurs during taro corm formation, whereas carbohydrates are synthesized during taro corm expansion.