We generated triploid hybrids of I. trifida and I. tabascana, providing insights into sweetpotato evolution and bridge germplasm for genetic improvement. Sweetpotato [Ipomoea batatas (L.) Lam.] (2n = 6x = 90) is an important root crop whose genomic polyploidisation process remains incompletely understood and highly complex. Its wild relatives are favoured for the study of genome formation, polyploidy processes and genetic improvement in sweetpotato. In this study, we obtained two triploid hybrids via reciprocal crosses between the closest diploid (I. trifida, 2n = 2x = 30) and the closer tetraploid (I. tabascana, 2n = 4x = 60) wild relatives of sweetpotato. To verify the authenticity of these two hybrids, molecular marker analysis, flow cytometry analysis, chromosome counting, morphological characterisation, pollen viability testing and meiotic observation were performed. Through InDel marker analysis, nine primer pairs consistently amplified parent-specific bands in the hybrids. Ploidy characterisation showed that both hybrids were triploid with 45 chromosomes. Morphologically, the two hybrids inherited many traits from both parents whilst producing some variation, such as both round and pentagonal corollas and purple stigmas with two or three lobes. Some pollen grains from the hybrids were fertile. The hybrids showed many abnormalities during meiosis, such as lagging chromosomes and uneven chromosome distribution. The triploid hybrids produced in this study can be used to infer early triploid genomic events during the origin and evolution of sweetpotato and to develop bridge germplasm for its genetic improvement.

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.

The lack of genomic and genetic research on wild sweetpotato species has hindered the advancement of sweetpotato variety development through modern crop improvement techniques. To facilitate the use of genomic and genetic approaches in sweetpotato variety development, we conducted a comprehensive assessment of the genome size and ploidy of six closely related wild sweetpotato species using flow cytometry and chromosome counting. Additionally, we acquired insights into their genomic characteristics through high-throughput sequencing. Based on the 17-mer frequency distribution, the genome sizes of these species ranged from 518.47 Mb to 1,505.04 Mb. Notably, most diploid species exhibited genome sizes of approximately 500 Mb, with the diploid wild species I. purpurea standing out as having a significantly larger genome size compared to other diploid species. A substantial proportion of repeats (ranging from 57.47 to 81.07

植物萜烯合酶是萜类化合物生物合成的关键酶，可催化异戊二烯前体形成各种萜类产物。尽管甘薯作为主要食物来源具有全球重要性，但对其萜烯合酶基因的研究仍然有限。因此，我们对甘薯TPS基因家族进行了全面的基因组分析，包括染色体分布、启动子元件和基因结构组成。在本研究中，我们在甘薯基因组中鉴定了119个IbTPS。通过同源进化树分析，这些基因被分为六个亚家族。此外，与其他六个物种的共线性分析为IbTPS的进化提供了有价值的见解基因。结合转录组数据和 qRT-PCR 分析，我们揭示了这些基因对真菌胁迫的反应。进行生物信息学分析以检查六个亚家族的基序和保守域，以及它们启动子上的顺式作用元件。结合黑斑病胁迫下甘薯块茎代谢物检测数据，我们的研究结果表明IbTPS基因可能受激素调控。在这些基因中，来自IbTPS-a 的IbTPS36在黑斑病胁迫下分离并克隆出IbTPS36家族，通过酵母异源表达、化合物分离纯化鉴定等实验方法，证实IbTPS36是一种高效、特异的β-硒烯合酶，推测β-硒烯的合成涉及香叶烯倍半萜环化和碳阳离子迁移，该研究对推进甘薯遗传资源开发和萜类化合物的生物合成具有重要意义。

Sweetpotato is an important crop that exhibits hexaploidy and high heterozygosity, which limits gene mining for important agronomic traits. Here, 314 sweetpotato germplasm resources were deeply resequenced, and 4 599 509 SNPs and 846 654 InDels were generated, among which 196 124 SNPs were nonsynonymous and 9690 InDels were frameshifted. Based on the Indels, genome-wide marker primers were designed, and 3219 of 40 366 primer pairs were selected to construct the core InDel marker set. The molecular ID of 104 sweetpotato samples verified the availability of these primers. The sweetpotato population structures were then assessed through multiple approaches using SNPs, and diverse approaches demonstrated that population stratification was not obvious for most Chinese germplasm resources. As many as 20 important agronomic traits were evaluated, and a genome-wide association study was conducted on these traits. A total of 19 high-confidence loci were detected in both models. These loci included several candidate genes, such as IbMYB1, IbZEP1, and IbYABBY1, which might be involved in anthocyanin metabolism, carotenoid metabolism, and leaf morphogenesis, respectively. Among them, IbZEP1 and IbYABBY1 were first reported in sweetpotato. The variants in the promoter and the expression levels of IbZEP1 were significantly correlated with flesh color (orange or not orange) in sweetpotato. The expression levels of IbYABBY1 were also correlated with leaf shape. These results will assist in genetic and breeding studies in sweetpotato.

Background Sweetpotato is an important vegetable and food crop that is bred through sexual crosses and systematic selection. The use of in vitro germination of sweetpotato pollen to test its viability has important theoretical and practical implications for improving the efficiency of sweetpotato crossbreeding by controlling pollination and conducting research on sweetpotato pollen biology. Results In this study, we observed the morphological structure of sweetpotato pollen under a scanning electron microscope (SEM), developed an effective method for the in vitro germination of sweetpotato pollen, and examined the viability of sweetpotato pollen after treating plants at different temperatures before blossoming. Sweetpotato pollen grains are spherical, with an average diameter of 87.07 ± 3.27 μm (excluding spines), with multiple germination pores and reticulate pollen surface sculpture. We applied numerous media to sweetpotato pollen germination in vitro to screen the initial medium and optimised the medium components through single-factor design. The most effective liquid medium for in vitro sweetpotato pollen germination contained 50 g/L Sucrose, 50 g/L Polyethylene glycol 4000 (PEG4000), 100 mg/L Boric acid and 300 mg/L Calcium nitrate, with a pH = 6.0. The optimum growth temperature for pollen development in sweetpotato was from 25 to 30 °C. Neither staining nor in situ germination could accurately determine the viability of sweetpotato pollen. Conclusions In vitro germination can be used to effectively determine sweetpotato pollen viability. The best liquid medium for in vitro germination of sweetpotato pollen contained 50 g/L Sucrose, 50 g/L Polyethylene glycol 4000 (PEG4000), 100 mg/L Boric acid and 300 mg/L Calcium nitrate, with the pH adjusted to 6.0. This study provides a reliable medium for the detection of sweetpotato pollen viability, which can provide a theoretical reference for sweetpotato genetics and breeding.

Adverse environmental stress is a major environmental factor threatening food security, which is why improving plant stress resistance is essential for agricultural productivity and environmental sustainability. The NAC (NAM, ATAF, and CUC) transcription factors (TFs) play a dominant role in plant responses to abiotic and biotic stresses, but they have been poorly studied in Ipomoea pes-caprae . In this research, 12 NAC TFs, named IpNAC1–IpNAC12, were selected from transcriptome data. The homologous evolution tree divided IpNACs into four major categories, and six IpNACs were linearly associated with Arabidopsis ANAC genes. From the gene structures, protein domains, and promoter upstream regulatory elements, IpNACs were shown to contain complete NAC-specific subdomains (A–E) and cis-acting elements corresponding to different stress stimuli. We measured the expression levels of the 12 IpNACs under abiotic stress (salt, heat, and drought) and hormone treatment (abscisic acid, methyl jasmonate, and salicylic acid), and their transcription levels differed. IpNAC5/8/10/12 were located in the nucleus through subcellular localization, and the overexpressing transgenic Arabidopsis plants showed high tolerance to salt stress. The cellular Na + homeostasis content in the mature and elongation zones of the four IpNAC transgenic sweetpotato roots showed an obvious efflux phenomenon. These conclusions demonstrate that IpNAC5/8/10/12 actively respond to abiotic stress, have significant roles in improving plant salt tolerance, and are important salt tolerance candidate genes in I . pes-caprae and sweetpotato. This study laid the foundation for further studies on the function of IpNACs in response to abiotic stress. It provides options for improving the stress resistance of sweetpotato using gene introgression from I . pes-caprae .

通过使用20％聚乙二醇(PEG)-6000模拟干旱环境验证光合参数对于甘薯抗旱评价的适用性,并优化甘薯抗旱评价方法.结果表明,通过丙二醛(MDA)含量和相对含水量(RWC)变化值鉴定了3个甘薯栽培种的耐旱性,24、72 h干旱胁迫下甘薯抗旱性表现一致,均为潮薯1号抗旱性最强,徐薯18居中,福薯7-6最弱.分别测量3、24 h干旱胁迫处理下净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)4个光合参数的变化值,24 h干旱胁迫下光合参数的变化与MDA含量和RWC变化一致.相关性分析结果表明,4个光合参数与MDA含量、RWC均有极显著相关性,其中Ci与MDA含量、RWC的相关系数均最大,证明了4个光合参数均可作为抗旱评价指标.对24 h干旱胁迫下4个光合参数的变化值进行主成分分析,第1主成分的特征值为3.90,累计贡献率达到97.39％,基于主成分分析方法利用光合参数建立了甘薯抗旱性综合评价指数模型.

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.

Background Sweetpotato ( Ipomoea batatas [L.] Lam.) is an important food crop. However, the genetic information of the nuclear genome of this species is difficult to determine accurately because of its large genome and complex genetic background. This drawback has limited studies on the origin, evolution, genetic diversity and other relevant studies on sweetpotato. Results The chloroplast genomes of 107 sweetpotato cultivars were sequenced, assembled and annotated. The resulting chloroplast genomes were comparatively analysed with the published chloroplast genomes of wild species of sweetpotato. High similarity and certain specificity were found among the chloroplast genomes of Ipomoea spp. Phylogenetic analysis could clearly distinguish wild species from cultivars. Ipomoea trifida and Ipomoea tabascana showed the closest relationship with the cultivars, and different haplotypes of ycf1 could be used to distinguish the cultivars from their wild relatives. The genetic structure was analyzed using variations in the chloroplast genome. Compared with traditional nuclear markers, the chloroplast markers designed based on the InDels on the chloroplast genome showed significant advantages. Conclusions Comparative analysis of chloroplast genomes of 107 cultivars and several wild species of sweetpotato was performed to help analyze the evolution, genetic structure and the development of chloroplast DNA markers of sweetpotato.

[目的]筛选感甘薯病毒病(SPVD)甘薯脱毒组培苗快繁最佳激素组合,为甘薯脱毒种苗在生产上的应用提供技术支撑.[方法]以徐薯22和阜徐薯20为试验材料,通过不同脱毒次数、病毒抑制剂、浓度激素(NAA/6-BA)组合、继代培养时间及炼苗等条件对茎尖分生组织培养,检测不同处理对SPVD的脱除率,测量组培苗株高,统计移栽成活率.[结果]甘薯褪绿矮化病毒(SPCSV)一次茎尖分生组织培养脱除率达100％,甘薯羽状斑驳病毒(SPFMV)二次茎尖分生组织培养脱除率达100％;病毒抑制剂宁南·嘧肽预处理SPFMV茎尖脱除率达100％;徐薯22组培苗快繁最佳激素组合为0.05 mg/L NAA、1.0 mg/L 6-BA,阜徐薯20组培苗快繁最佳激素组合为0.01 mg/L NAA、1.0 mg/L 6-BA;徐薯22和阜徐薯20炼苗处理在继代培养60 d时,最高成活率达86.67％和83.33％.[结论]二次茎尖分生组织培养可完全脱除SPVD,病毒抑制剂宁南·嘧肽预处理可提高SPFMV茎尖脱除率,组培苗快繁的最佳激素组合为0.01～0.05 mg/L NAA、1.0 mg/L 6-BA,炼苗可显著提高组培苗移栽成活率.

Wild relatives of crops are often rich in genetic resources and provide great possibilities for crop improvement. Ipomoea pes-caprae is one of the wild relatives of sweet potato and has high salt tolerance. Transcriptomes in the treatment and control groups at various times were sequenced to identify salt tolerance genes and salt response pathways. A total of 40,525 genes were obtained, of which 2478 and 3334 were differentially expressed in the roots and leaves of I. pes-caprae under salt stress, respectively. Identification of candidate genes revealed that the mitogen-activated protein kinase (MAPK) signaling pathway of plants and plant hormone signal transduction participates in the salt signal of I. pes-caprae under salt stress. Homology to ABI2 (HAB2) and Clade A protein phosphatases type 2C (HAI1), which encode two protein phosphatases 2C (PP2C) in the abscisic acid (ABA) signal pathway, were continuously up-regulated upon salt stress, indicating their key role in the salt signal transduction pathway of I. pes-caprae. The expression of EIN3-binding F-box protein 1 (EBF1) in the ethylene signaling pathway was also up-regulated, revealing that the salt tolerance of I. pes-caprae was related to the scavenging of reactive oxygen species (ROS). This study provides insights into the mechanism of salt-tolerant plants and the mining of salt-tolerant genes in sweet potato for the innovation of germplasm resources.

以25份甘薯登记品种幼嫩根系为实验材料,采用改良硫酸镁裂解液的方法和PI荧光染色技术,以已知大豆(Glycine max(Linn.)Merr.)Williams 82基因组大小为对照,使用流式细胞术对25份甘薯登记品种基因组大小进行测定.结果表明:25份甘薯登记品种基因组大小范围为1.469～1.716 pg,平均为1.568 pg,其中泉薯17的最大,为1.716 pg;漯紫1号的最小,为1.469 pg.测定结果可为甘薯全基因组测序、泛基因组测序和基因组重测序等研究提供数据参考.

该研究基于TP-M13-SSR分子标记荧光毛细管检测技术,以中国已入库登记的99份甘薯品种为材料,利用SSR标记建立登记品种的“01”数据库,导入DPS软件计算不同品种之间的遗传距离,采用MEGA的邻接法进行聚类分析,并利用Structure混合模型对材料进行遗传结构分析,以探讨各品种的遗传构成以及品种间的亲缘关系,揭示中国甘薯登记品种在DNA水平的相似度,为甘薯品种鉴定、亲本选配和品种改良等提供参考.结果 显示:(1)28对引物共扩增出162条谱带,多态率为96.30％,每对引物平均获得5.57条多态性谱带.(2)构建了99份甘薯登记品种的遗传进化树,99份品种的遗传距离在0～0.464 6之间,平均遗传距离为0.307 7;在遗传距离为0.267 0处将99份品种分为3个类群,且同一生态薯区的品种或具有同一亲本的品种首先被聚在一起,但不同生态薯区的品种在各类群中相对分散分布.(3)品种间的遗传基础较窄,部分生态薯区的品种相似性较高;群体结构分析将材料分为3个亚群,与聚类分析分群结果基本一致,其中31份材料拥有混合来源,遗传背景较为复杂.

通过SSR分子标记,对112份甘薯引进种进行了遗传多样性和群体结构分析,并与中国地方种进行了聚类比较分析.研究了中国目前保存最多的甘薯引进种间的遗传多样性和亲缘关系,以及与地方种间的遗传多样性关系.用SSR建立研究材料的0,1数据库,用ntsys-pc 2.10软件计算遗传距离矩阵并导入MEGA 6.06聚类,利用STRUCTURE 2.3.4软件对112份引进种进行群体结构分析,并将112份引进种与58份中国地方种共170份进行聚类分析.结果表明:112份材料的平均遗传距离为0.552,遗传距离分布在0.031到0.949范围之内.使用Neighbor-Joining(NJ)聚类法,在遗传距离为0.442处将112份材料分成9个类群,其中类群9又在遗传距离为0.428处,分为3个亚群.亚群ⅨC含有39份材料,该亚群主要来自南美洲,聚类集中,血缘较为单一.通过群体结构分析将112份材料划分成了2个群体,通过对引进种的来源地比较分析,发现来自南美洲与其他地区种质材料分属于2个群体.通过对引进种和地方种共计170份甘薯资源聚类比较分析,发现中国大陆地方种与中国台湾品种间亲缘关系最近,与东南亚、东北亚、南美洲甘薯引进种间亲缘关系较近,与国际马铃薯中心、国际热带农业研究所的材料和世界蔬菜中心的材料亲缘关系较远.