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.

Starch, a key biological macromolecule accounting for 50-80% of dry weight in sweetpotato (Ipomoea batatas [L.] Lam.) storage roots, underpins food and industrial applications. However, sweetpotato starch characterization is limited by local-sectioning approaches that fail to capture the whole-root granule dynamics. Here, we established a new morphological observation system covering three key root regions based on two representative cultivars: Okinawa 100 (V100), and Yanshu25 (Y25). It was effective and convenient for in situ starch observation and analysis in sweetpotato roots. The whole-root in situ microscopy, starch physicochemical profiling, and transcriptomic correlation were integrated to resolve starch dynamics in Y25 and V100. We identified widespread simple starch granules (SSGs)-compound starch granule (CSG) coexistence across the whole root tissues, with Y25 exhibiting programmed CSG fragmentation driven by ARCs/FtsZ-mediated amyloplast envelope destabilization and concomitant AMY/BMY upregulation. Y25 had a higher amylose content and a higher proportion of medium/long chains, but the average degree of polymerization was slightly lower. Transcriptomic analyses revealed that the differentially expressed genes were annotated in pathways of carbohydrate metabolism, and the differentially expressed genes in the starch metabolism pathway were analyzed. Weighted gene co-expression network analysis further identified the hub genes from different modules and analyzed the co-expression networks. This work will not only advance the understanding of starch granule assembly and remodeling in sweetpotato, but also provide a robust methodological and transcriptome-guided framework for starch-focused germplasm screening and quality improvement.

To uncover the variation patterns of the nutritional components in sweetpotato storage roots during long-term storage comprehensively, the general nutrients, phytochemicals, and starch properties of nine sweetpotato varieties with different flesh colors were quantified and analyzed by chemical and physical techniques. During the storage, the starch content decreased firstly and then increased, with sugar content the opposite. The crude protein content and the total dietary fiber content both increased continuously. The β-carotene content decreased or kept constant, while the anthocyanin content showed different variation patterns in the three purple-fleshed varieties. The four types of polyphenols and two types of flavonoids showed no obvious content changes during the storage. The amylose contents of all varieties showed various patterns, while the crystallinity was C-type. The proportion of small-sized starch granules reduced, and the combined proportion of medium-sized and large-sized granules increased. New correlations among the nutritional parameters for each variety were revealed for the first time. Principal component analysis indicated that the orange-fleshed varieties were distinguished from other varieties. Finally, the most storage-resistant variety ZZ3 and the suitable variety for each quality trait was selected. This study provides not only theoretical basis for comprehensive understanding of the nutrient’s variations in sweetpotato storage roots during long-term storage, but also guidelines for evaluation of nutritional quality of sweetpotato roots during storage and improvement of storage methods.

The National Sweetpotato Genebank in Vitro (Xuzhou, China) recently collected 1183 sweetpotato accessions, including potential duplicates. To assess genetic diversity and identify redundant accessions, we conducted comprehensive analyses using seven SSR (Simple Sequence Repeat) marker pairs coupled with agronomic trait evaluation. These markers demonstrated high polymorphism, with an average PIC (Polymorphic Information Content) value of 0.7821. Genetic distance-based clustering revealed the genetic similarity among accessions originating from the same geographic regions. Molecular analysis identified 543 duplicates (each sharing zero genetic distance with at least one counterpart) among the 1183 accessions, while 640 accessions were confirmed as genetically unique. Further classification of the 543 duplicates resulted in 130 distinct genetic groups based on zero genetic distance. Subsequent phenotypic characterization, including evaluations of skin color, flesh color, and aboveground morphological traits, revealed 190 additional unique accessions within these groups. Combining these with the initial 640 unique accessions yielded a final collection of 830 genetically distinct germplasm resources. This study significantly enhances germplasm identification efficiency for conservation purposes, provides valuable insights into the genetic diversity and geographical distribution patterns of sweetpotato germplasm, and underscores the importance of targeted collection efforts in regions exhibiting high genetic diversity.

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.

[Objective]The purpose of this study was to analyze the quantitative trait loci(QTLs)related to stem nematode resistance in sweetpotato(Ipomoea batatas(L.)Lam.),lay a foundation for the fine mapping,cloning,and functional analysis of stem nematode resistance genes in sweetpotato.It also aimed to provide support for the study of the genetic mechanisms of stem nematode resistance,as well as the breeding of resistant varieties in sweetpotato.[Method]An F1 population of 212 progenies derived from a cross between the highly resistant cultivar Yushu 10 and the susceptible line Xin 24 was used.In this study,field-based natural infection assays were conducted to evaluate stem nematode resistance.QTL mapping was performed using composite interval mapping(CIM),and candidate genes within QTL confidence intervals were predicted.Additionally,genome-wide association studies(GWAS)were carried out using the rMVP software(a memory-efficient,visualization-enhanced,and parallel-accelerated R package).For further validation,the resistant cultivar Zhenghong 22 was artificially inoculated with D.destructor,and samples were collected at different post-inoculation time points.The expression patterns of five candidate genes(itf02g19880,itf02g20080,itf02g20100,itf13g18480 and itf13g18550)were analyzed via qRT-PCR.[Result]Three QTLs(qSNR02-1,qSNR02-2,and qSNR13-1)were identified,distributed on chromosomes 2 and 13.The phenotypic contribution rate of the individual QTL related to stem nematode resistance ranged from 9.6％to 11.7％.GWAS revealed one significantly associated locus with stem nematode resistance on chromosome 6.Based on the genomic annotation information,36 candidate genes related to stem nematode resistance were predicted within the QTL confidence intervals,including members of the ABC transporter family,multidrug and toxic compound extrusion(MATE)efflux proteins,E3 ubiquitin ligases,and glutathione S-transferases,which are involved in defense mechanisms,post-translational modification,and stress response.qRT-PCR results showed that the expression patterns of the five candidate genes were significantly different.The expression level of itf02g20100 reached a peak at 3 days after inoculation,which was 6.2 times that of the control;the expression level of itf02g19880 increased sharply and reached the highest level at 0.5 days after inoculation,which was 43.2 times that of the control;the expression patterns of itf13g18480 and itf13g18550 were similar,and both reached a peak at 7 days after inoculation.This indicates that different candidate genes may play different regulatory roles in the defense response after Ditylenchus destructor infection.[Conclusion]Three QTLs related to stem nematode resistance in sweetpotato were identified,and 36 related candidate genes were screened out,which can be used for the subsequent cloning and functional study of genes related to stem nematode resistance in sweetpotato.

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.

Sweetpotato, Ipomoea batatas (L.) Lam., is an important worldwide crop used as feed, food, and fuel. However, its polyploidy, high heterozygosity and self-incompatibility makes it difficult to study its genetics and genomics. Longest vine length (LVL), yield per plant (YPP), dry matter content (DMC), starch content (SC), soluble sugar content (SSC), and carotenoid content (CC) are some of the major agronomic traits being used to evaluate sweetpotato. However limited research has actually examined how these traits are inherited. Therefore, after selecting 212 F1 from a Xin24 × Yushu10 crossing as the mapping population, this study applied specific-locus amplified fragment sequencing (SLAF-seq), at an average sequencing depth of 26.73× (parents) and 52.25× (progeny), to detect single nucleotide polymorphisms (SNPs). This approach generated an integrated genetic map of length 2441.56 cM and a mean distance of 0.51 cM between adjacent markers, encompassing 15 linkage groups (LGs). Based on the linkage map, 26 quantitative trait loci (QTLs), comprising six QTLs for LVL, six QTLs for YPP, ten QTLs for DMC, one QTL for SC, one QTL for SSC, and two QTLs for CC, were identified. Each of these QTLs explained 6.3 to 10% of the phenotypic variation. It is expected that the findings will be of benefit for marker-assisted breeding and gene cloning of sweetpotato.

BACKGROUND:The utilization of sweetpotato starch in the food industry is significantly influenced by the granule size of the starch. To isolate sweetpotato starch fractions with different sizes, an efficient isolation method is in demand. The differences in thermal properties of starch fractions with different sizes from various sweetpotato varieties were revealed insufficiently. RESULTS:In this study, we devised a time-saving isolation technique to effectively isolate sweetpotato starch fractions based on granule sizes. The new technique was proved applicable for sweetpotato varieties with different flesh colors. The amylose contents of the isolated starch fractions were in the range 16.49-23.27%. A positive association was observed between amylose content, relative crystallinity of starch fractions and their granule size. Conversely, both the swelling power and water solubility at 95 °C displayed a consistent decline from more than 30 g g-1 to lower than 20 g g-1 as the granule size increased. Tp, To and Tc decreased gradually with an increase of starch granule size, while the medium- or small-sized starch fractions showed higher ΔH. In the first stage of thermogravimetric analysis curves, the weight of the small-sized starch fractions decreased the slowest, but no definite pattern was detected in the second or third stage. CONCLUSION:Therefore, the newly established technique and the results of this study will help better understand the properties of sweetpotato starch fractions with different sizes and certainly provide guidelines for the utilization of sweetpotato starch in food processing and product development. © 2024 Society of Chemical Industry.

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.

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.

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.] is a major tuberous root crop that is rich in flavonoids. Here, we discovered a spontaneous mutation in the color of the leaf vein base (LVB) and root skin (RS) in the Zheshu 81 cultivar. The flavonoid and anthocyanin metabolites and molecular mechanism were analyzed using metabolome and transcriptome data. Compared to the wild type, 13 differentially accumulated metabolites (DAMs) in the LVB and 59 DAMs in the RS were all significantly downregulated. Moreover, all the anthocyanin metabolites decreased significantly. The differentially expressed genes (DEGs) encoding the key enzymes in the later enzymatic reaction of anthocyanin and flavonoid were significantly downregulated in the mutant. The expression trends of the transcription factor MYB were evidently related to the anthocyanin content. These results offer insights into the coloration in the LVB and RS and a theoretical basis for determining the regulation of flavonoid and anthocyanin synthesis in sweetpotato.

对甘薯、番茄、拟南芥中63个SPL基因家族进行了系统进化树分析、保守蛋白基序(Motif)分析,筛选归纳出同源性较高的2个分支的12个SPL基因进行理化性质分析、核定位预测等,氨基酸序列比对结果表明这些基因的功能可能较为保守.通过对番茄中的SPL基因Solyc05g015510.2、Solyc10g078700.1进行表达量分析,发现这2个基因可能参与调控果实成熟衰老进程.另外,通过对非生物胁迫下的转录水平进行分析得知,拟南芥中的AT5G43270可能参与对盐胁迫、热胁迫条件下的响应,AT1G27360、AT1G27370可能参与热胁迫条件下的响应,AT2G42200可能参与冷胁迫条件下的响应,而AT3 G57920在非生物胁迫条件下表达量没有特别明显的变化,表明AT3 G57920可能不参与非生物胁迫下的响应.

以来自不同育种单位的54份橘肉甘薯和52份紫肉甘薯品种资源为材料,测定块根中淀粉、可溶性糖、还原糖、粗蛋白、β-胡萝卜素和花青苷的含量.结果表明,橘肉甘薯的可溶性糖和还原糖含量通常高于紫肉甘薯,淀粉含量低于紫肉甘薯,粗蛋白含量与紫肉甘薯类似;橘肉甘薯的β-胡萝卜素含量为0.4～280.7μg/g,紫肉甘薯的β-胡萝卜素含量最高为31.8μg/g,花青苷含量为15.0～20.0μg/g.相关性分析结果表明,淀粉含量和可溶性糖含量、还原糖含量呈极显著负相关.基于6种营养物质的含量,分别将橘肉甘薯和紫肉甘薯品种资源聚为5个和4个类群;其中,二者均为第II类群种质资源综合品质较好.本研究结果为这些甘薯品种资源的加工利用及品种改良提供理论参考和材料基础.

为了解紫肉甘薯中花青苷的组分构成及多样性分布,以来自国内外多家培育单位的68份紫肉甘薯品种资源为试验材料,利用液质联用技术测定了 6类共计68种花青苷的含量.结果表明,6类花青苷中,矢车菊类和芍药类花青苷的含量较高,分布范围较广,天竺葵类花青苷的含量整体最低,分布范围最狭窄.相关性分析结果表明,检测到花青苷的总含量和矢车菊类、芍药类及矮牵牛类花青苷的含量均呈极显著正相关.系统聚类分析结果表明,68份紫肉甘薯品种资源被聚为6个类群,其中第Ⅱ类群6类花青苷的含量均较高,第Ⅳ类群各类花青苷的含量均较低.68种花青苷在68份紫肉甘薯品种中的检出情况表明,有7种花青苷能够在全部的紫肉甘薯品种中检出,10种只能在少于50份的材料中检出.68种花青苷含量的相关性分析结果表明,每类花青苷中均有几种花青苷的含量相等或呈极显著正相关.本研究通过对紫肉甘薯品种资源花青苷组分构成及多样性的分析与评价,筛选出6类花青苷含量较高的紫肉甘薯品种3份,单类花青苷含量较高的品种7份,为优质甘薯的推广和后续优质品种的选育提供了材料基础.

Sweet potato decays easily due to its high respiration rate and reactive oxygen species (ROS) accumulation during postharvest storage. In this study, we explored the relationship between antioxidant capacity in leaves and storage properties in different sweet potato cultivars, the tuberous roots of 10 sweet potato cultivars were used as the experimental materials to analyze the storage property during storage at 11–15°C. According to the decay percentage after 290 days of storage, Xu 32 was defined as a storage-tolerant cultivar (rot percentage less than 25%); Xu 55-2, Z 15-1, Shangshu 19, Yushu, and Zhezi 3 as above-moderate storage-tolerant cultivars (rot percentage ranging from 25 to 50%); Sushu 16, Yanshu 5, and Hanzi as medium-storable cultivars (rot percentage 50–75%); and Yan 25 as a storage-sensitive cultivar (rot percentage greater than 75%). Meanwhile, analysis of the α-amylase activity in root tubers of the 10 sweet potato cultivars during storage indicated that α-amylase activity was lowest in the storage-tolerant cultivar Xu 32 and highest in the storage-sensitive cultivar Yan 25. Evaluation of antioxidant enzyme activities and ROS content in the leaves of these 10 cultivars demonstrated that cultivar Xu 32, which showed the best storage property, had higher antioxidant enzyme activity [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD)] but lower lipoxygenase (LOX) activity, hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) contents, and superoxide anion radical (O 2 ⋅ – ) production rates compared with those of the storage-sensitive cultivar Yan 25 and the medium-storability cultivars Hanzi, Yanshu 5, and Sushu 16. Additionally, principal component analysis (PCA) suggested that sweet potato cultivars with different storage properties were clustered separately. Correlation and heat map analysis further indicated that CAT, APX, POD, and SOD activities were negatively correlated with α-amylase activity, while LOX activity and MDA and H 2 O 2 contents were negatively correlated with the storage property of sweet potato. Combined, our findings revealed that storage property is highly correlated with antioxidant capacity in sweet potato leaves and negatively correlated with α-amylase activity in tuberous roots, which provides a convenient means for the screening of storage-tolerant sweet potato cultivars.

甘薯采后贮藏期短,在采后贮运过程中极易腐败变质,从而影响甘薯的品质,造成大量损失.因此,研究不同耐贮性甘薯的生理生化指标差异具有重要的理论与实践价值.以耐贮藏甘薯品种南瑞苕、奥墨红、徐55-2、新大紫、徐薯18和不耐贮藏甘薯品种徐薯23、大红花、南瓜薯、满村香、万二、金吊薯为试验材料,考察甘薯叶片中抗氧化酶活性及活性氧(ROS)含量的差异,解析抗氧化代谢与甘薯耐贮性的相关性.结果表明,与不耐贮藏甘薯品种相比,耐贮的甘薯品种抗氧化酶如超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性较高,脂氧合酶(LOX)活性、丙二醛(MDA)含量、过氧化氢(H2O2)含量和超氧阴离子(O2-·)产生速率相对较低.热图分析结果显示,耐贮藏甘薯品种的叶片抗氧化酶活性相对较高,活性氧含量相对较低,不耐贮藏甘薯品种的叶片抗氧化酶活性相对较低,活性氧含量相对较高.主成分分析结果表明,不同耐贮性的甘薯品种中抗氧化能力和贮藏性能之间呈正相关.相关性分析结果显示,不同抗氧化酶之间有着较高的正相关系数,而与LOX活性、H2O2含量、O2-·产生速率、MDA含量呈明显负相关.由此可见,耐贮藏甘薯品种较不耐贮藏甘薯品种有着更好的抗氧化能力.研究结果为耐贮甘薯的选育提供了理论参考.

The complexity of sweetpotato genome, including hexaploidy and heterozygosity, has hindered genetic studies on agronomically important traits such as storage root formation and thickening. Ipomoea trifida (H. B. K.) G. Don. (2n = 2x = 30) is closely related to and cross-compatible with sweetpotato. The diploid I. trifida has been developed as a model plant for sweetpotato genetic research, due to its low ploidy and simple genetic background. In order to reveal the molecular mechanisms underlying storage root development in sweetpotato, F1 mapping population derived from diploid I. trifida was screened for root diameter by genotyping-by-sequencing method. A total of 11,555 raw polymorphic SNPs were identified, in which 8454 SNPs can be used in this F1 population. The SNP genotyping data was utilized to construct the genetic linkage map of I. trifida. The maternal and paternal linkage maps were produced, and 904 maternal and 2034 paternal markers resulted in 13 and 15 LGs respectively. The total length of the maternal maps covered 842.34 cM, while the paternal maps spanned 1540.98 cM. The integrated genetic map consisted of 2892 SNPs (average of 193 markers/linkage group) on 15 linkage groups (LGs) covering 1550.22 cM of the whole genome at an average inter marker distance of 0.55 cM. By using the phenotypic data obtained in this study, three significant QTL were detected for root diameter. These QTL were distributed among three LGs at three independent positions, and each QTL explained significant amount of phenotypic trait variation ranged from 6.1 to 12.0%. The qRD-2 QTL explained 12.0% of the phenotypic variation. This study results will assist in the map-based cloning of genes controlling storage root-related traits and further helps to reveal the genetic basis of root development in sweetpotato.