Development of SRAP Markers Linked to a Gene for Stem Nematode Resistance in Sweetpotato, Ipomoea batatas (L.) Lam.

Sequence-related amplification polymorphism （SRAP） markers closely linked to stem nematode resistance gene were developed in sweetpotato, lpomoea batatas （L.） Lam. Using bulked segregant analysis （BSA）, 200 SRAP primer combinations were screened with the resistant and susceptible bulked DNA from the 196 progenies of an F1 single-cross population of resistant parent Xu 781xsusceptible parent Xushu 18, 77 of them showed polymorphic bands between resistant and susceptible DNA. Primer combinations detecting polymorphism between the two bulks were used to screen both parents and 10 individuals from each of the bulks. The results showed that primer combination A9B4 produced 3 specific bands in the resistant plants but not in the susceptible plants, suggesting that the markers, named Nspl, Nsp2 and Nsp3, respectively, linked to a gene for stem nematode resistance. Primer combination A3B6 also produced a SRAP marker named Nsp4 linking to the resistance gene. Amplified analysis of the 196 F1 individuals indicated that the genetic distance between these markers and the resistance gene was 4.7, 4.7, 6.3, and 9.6 cM, respectively.

Analysis of drought tolerance and genetic and epigenetic variations in a somatic hybrid between Ipomoea batatas (L.) Lam. and I. triloba L.

The somatic hybrid KT1 was previously obtained from protoplast fusion between sweetpotato （Ipomoea batatas （L.） Lam.） cv. Kokei No. 14 and its wild relative I. triloba L. However, its genetic and epigenetic variations have not been investigated. This study showed that KT1 exhibited significantly higher drought tolerance compared to the cultivated parent Kokei No. 14. The content of proline and activities of superoxide dismutase （SOD） and photosynthesis were significantly increased, while malonaldehyde （MDA） content was significantly decreased compared to Kokei No. 14 under drought stress. KT1 also showed higher expression level of well-known drought stress-responsive genes compared to Kokei No. 14 under drought stress. Amplified fragment length polymorphism （AFLP） and methylation-sensitive amplified polymorphism （MSAP） analyses indicated that KT1 had AFLP and MSAP band patterns consisting of both parent specific bands and changed bands. Fur- ther analysis demonstrated that in KT1. the proportions of Kokei No. 14 specific genome components and methylation sites were much greater than those of I. triloba. KT1 had the same chloroplast and mitochondrial genomes as Kokei No. 14. These results will aid in developing the useful genes ofI. triloba and understanding the evolution and phylogeny of the cultivated sweetpotato.

Comparison of Physicochemical,Organoleptic and Nutritional Abilities of Eight Sweet Potato(Ipomoea batatas)Varieties

In Martinique (F.W.I.), biodiversity of vegetable varieties remain unexploited due to public unawareness or supply problems. To further enhance the sweet potato, physicochemical, sensory and nutritional characteristics of eight varieties of sweet potato were established. The eight sweet potatoes cultivars were noticeably diverse with phenotypic, sensory, physicochemical and nutritional characteristics which were very varied. The eight cultivars grown in Martinique were advantageously positioned in relation to the globally identified sweet potato, regarding fibre, starch, potassium, copper, vitamin B1, B3 and B9 contents. Compared to the ordinary potato, Martiniquan sweet potatoes have a much better nutritional potential. Energy value and vitamin C levels were twice as much as in normal potatoes. Martiniquan sweet potatoes cultivars were also richer in minerals and vitamins, with 2.7 times more vitamin B9 and 63 times more beta-carotene than the ordinary potato.

Correlation of phytochemical content with antioxidant potential of various sweet potato (Ipomoea batatas) in West Java, Indonesia

Objective: To determine antioxidant activity and phytochemical content from various tubers extracts of sweet potato(Ipomoea batatas) and to explore the correlation of phytochemical content with their antioxidant activities. Methods: Antioxidant activities were tested using DPPH and FRAP assays. Total phenolic was calculated by Folin-Ciocalteu reagent, flavonoid content by Chang's method and correlation with their antioxidant activities were analyzed by Pearson's method. Results: PO2 showed highest antioxidant activity, which had the lowest IC50 DPPH(10.54 μg/m L) and the lowest EC50 FRAP(11.14 μg/m L). PO2 showed the highest total phenolic(11.91 g GAE/100 g) and total flavonoid content(17.83 g QE/100 g). There were significantly negative correlation between total phenolic content and flavonoid content in sample PO with their IC50 DPPH and EC50 FRAP. IC50 DPPH of sample PP and PO showed significantly positive correlation with their EC50 FRAP. Conclusions: Result of DPPH method shows that all different ethyl acetate and ethanolic tubers extracts of four varieties of sweet potato are classified as strong and very strong antioxidant. Result of DPPH and FRAP methods indicates that phenolic and flavonoid compounds in sample PO contributes together to antioxidant activities. Antioxidant activities of sample PP and PO by DPPH method are linear to FRAP method.

Cloning and Characterization of Eukaryotic Translation Initiation Factor 4E (eIF4E) Gene Family in Ipomoea batatas L. (Lam) for Understanding Hexaploid Sweetpotato-Virus Interactions

Characterization of genes related to sweetpotato viral disease resistance is critical for understanding plant-pathogen interactions, especially with feathery mottle virus infection. For example, genes encoding eukaryotic translation initiation factor (eIF)4E, its isoforms, eIF(iso)4E, and the cap-binding protein (CBP) in plants, have been implicated in viral infections aside from their importance in protein synthesis. Full-length cDNA encoding these putative eIF targets from susceptible/resistant and unknown hexaploid sweetpotato (Ipomoea batatas L. Lam) were amplified based on primers designed from the diploid wild-type relative Ipomoea trifida consensus sequences, and designated IbeIF4E, IbeIF(iso)4E and IbCBP. Comparative analyses following direct-sequencing of PCR-amplified cDNAs versus the cloned cDNA sequences identified multiple homeoalleles: one to four IbeIF4E, two to three IbeIF(iso)4E, and two IbCBP within all cultivars tested. Open reading frames were in the length of 696 bp IbeIF4E, 606 bp IbeIF(iso)4E, and 675 bp IbCBP. The encoded single polypeptide lengths were 232, 202, and 225 amino acids for IbeIF4E, IbeIF(iso)4E, and IbCBP, with a calculated protein molecular mass of 26 kDa, 22.8 kDa, and 25.8 kDa, while their theoretical isoelectric points were 5.1, 5.57, and 6.6, respectively. Although the homeoalleles had similar sequence lengths, single nucleotide polymorphisms and multi-allelic variations were detected within the coding sequences. The multi-sequence alignment performed revealed a 66.9% - 96.7% sequence similarity between the predicted amino acid sequences obtained from the homeoalleles and closely related species. Furthermore, phylogenetic analysis revealed ancestral relationships between the eIF4E homeoalleles and other species. The outcome herein on the eIF4E superfamily and its correlation in sequence variations suggest opportunities to decipher the role of eIF4E in hexaploid sweetpotato feathery mottle virus infection.

Hypolipidemic and anti-atherosclerogenic effects of aqueous extract of Ipomoea batatas leaves in diet-induced hypercholesterolemic rats

Objective:Ipomoea batatas(L.)Lam.is a food plant used in African traditional medicine to treat cardiovascular diseases and related conditions.We assessed the hypolipidemic and anti-atherosclerogenic properties of the aqueous extract of I.batatas leaves in a rat model of diet-induced hypercholesterolemia.Methods:Hypercholesterolemia was induced in male Wistar rats by exclusive feeding with a cholesterolenriched(1%)standard diet for four weeks.Then,rats were treated once daily(per os)with I.batatas extract at doses of 400,500 and 600 mg/kg or with atorvastatin(2 mg/kg),for four weeks.Following treatment,animals were observed for another four weeks and then sacrificed.Aortas were excised and processed for histopathological studies,and blood glucose level and lipid profile were measured.Results:Hypercholesterolemic animals experienced a 21.5%faster increase in body weight,significant increases in blood glucose and blood lipids(148.94%triglycerides,196.97%high-density lipoprotein cholesterol,773.04%low-density lipoprotein cholesterol,148.93%very low-density lipoprotein cholesterol and 210.42%total cholesterol),and increases in aorta thickness and atherosclerotic plaque sizes compared to rats fed standard diet.Treatment of hypercholesterolemic rats with the extract mitigated these alterations and restored blood glucose and blood lipid levels to normocholesterolemic values.Conclusion:Our findings suggest that I.batatas leaves have hypolipidemic and anti-atherosclerogenic properties and justify their use in traditional medicine.

氮素不同控释期对甘薯光合特性及干物质积累与分配的影响

以甘薯[Ipomoea batatas(L.)Lam.]品种济薯25为试材,在大田条件下,设置控释期为30 d(T30)、50 d(T50)、70 d(T70)、90 d(T90)4个氮素控释肥处理,以施用等量养分含量的普通复合肥作为对照(CK),研究不同氮素控释期对甘薯光合特性及干物质积累与分配的影响。结果表明,氮素适当控释(控释期30~70 d)提高了甘薯中后期(80~160 d)叶片光合性能,促进了干物质向地下部的快速积累和转运分配,甘薯中后期叶片光合指标、地下部干物质积累(积累量和积累速率)和分配(分配比例和根冠比)指标均明显高于对照,其中以T50、T70较好,收获期(160 d)2个处理净光合速率、叶绿素SPAD、地下部干物质积累量、根冠比分别比对照提高了14.01%、11.32%、21.75%、18.48%和15.62%、11.84%、20.65%、18.84%;当控释期达90 d时,后期(120~160 d)地下部干物质积累与分配指标均低于对照,说明氮素控释期过长不利于甘薯后期干物质向地下部的快速积累和转运分配。

基于光谱反射率的甘薯叶片钾素营养监测与诊断

以商薯19和心香2个甘薯(Ipomoea batatas)品种为试验材料,通过设置不同梯度钾素处理测定叶片的光谱反射率,分别构建基于比值植被指数(RVI)的甘薯叶片钾含量和钾营养指数预测模型。结果表明,RVI与叶片钾含量构建的线性模型表明,RVI(R_(1598 nm),R_(1771 nm))对甘薯叶片钾含量的预测精度较高,回归方程为y=58.6010x-58.446(R^(2)=0.7414,RMSE=0.83),采用验证数据对线性模型进行检验,模型对不同钾肥水平处理下的甘薯叶片钾含量具有较好的预测能力(R^(2)=0.7324,RMSE=0.85);RVI与钾营养指数构建的线性模型表明,RVI(R_(700 nm),R_(1385 nm))对甘薯叶片钾营养指数的预测精度较高,回归方程为y=6.0329x-0.833(R^(2)=0.7688,RMSE=0.15),采用验证数据对线性模型进行检验,模型对不同钾肥水平处理下的甘薯叶片钾营养指数具有较好的预测能力(R^(2)=0.6395,RMSE=0.20);利用RVI能够较好监测与诊断甘薯钾素营养。

Influence of Sanitization Process on Maintaining Sweet Potato Quality for Export

The whole cold-chain for exporting sweet potato(native variety“Abees”),to foreign market included immediate curing operation directly after harvest helped in healing skin texture,however,in order to reduce postharvest soft rot(Rhizopus stolonifer)incidence following trimming,and washing,ultraviolet light(UV-C)treatment was used as a main sanitizer for eliminating the soft rot.Exposure of the roots to UV-C(254 nm)was applied in a UV-C room on freshly harvested and cured sweet potato while rolling up on a movable line at 20 cm distance for 1,2,and 3 hr.As combining UV-C treatment with chlorine(200 ppm)on roots,marked and significant reduction of the total microbial load and Rhizopus potential was achieved on root surfaces respectively compared with chlorine alone.It also reduced soft rot percentage to almost 0%infection.After 3 months of cold-storage,quality assessment of sweet potato showed that root characteristics were markedly maintained.The ability of UV-C light to induce phenylalanine ammonia lyase(PAL)enzyme activity in root tissue and maintain the activities of peroxidase and polyphenol oxidase,however with slight increase,was detected.UV-C caused an increase of phenol content in sweet potato tissue that made an activation of defense reaction against the rot causal pathogen.As the exposure time to UV-C light increased,a higher content of phenols occurred.Moreover,UV-C application caused decrease in sugar content of root tissue that is flavored by soft rot-causal pathogen.

优质甘薯品种湛薯16的选育及栽培技术

湛薯16是湛江市农业科学研究院采用五圃制法,从徐紫薯3号自然杂交后代中选育出来的优质甘薯[Ipomoea batatas(L.)Lam.]品种。在2019—2020年南方薯区甘薯新品系多点鉴定试验中,湛薯16鲜薯平均产量33280.05 kg/hm^(2),薯干平均产量9748.95 kg/hm^(2),淀粉平均产量6364.35 kg/hm^(2),平均干物率29.14%。该品种鲜薯产量高、熟食口感佳,中抗蔓割病,适宜按照栽培技术推广。

不同浓度生根粉对甘薯芽苗生根及扦插存活率的影响

以甘薯[Ipomoea batatas(L.)Lam.]品种普薯32号为研究对象,通过不同配比、不同浓度生根剂处理甘薯芽苗,研究不同处理对甘薯芽苗生根时间、生根数量、根长度及扦插存活率的影响。结果表明,IBA(吲哚丁酸)+NAA(萘乙酸)、ABT(生根粉)和清水处理均能使甘薯芽苗快速生根,而ABT浓度超过25 mg/L对甘薯芽苗生根会有一定的抑制作用,从而降低生根数量。当甘薯芽苗生根数量随着ABT剂量增加而减少时,单根长度不会出现明显变长的现象,根总长度与生根数量整体呈正相关。甘薯芽苗生根后扦插可显著提升芽苗的存活率,各生根剂处理芽苗存活率均高于清水对照;甘薯芽苗的存活率与芽苗生根数量和根总长度有一定的关联。

遮阳水平对不同类型甘薯生长发育和品质性状的影响

对3个不同类型的甘薯(紫肉型甘薯鄂薯12、淀粉型甘薯鄂薯15、鲜食型甘薯鄂薯17)在3个遮阳水平条件下(0、30%、70%)下进行光合色素、农艺性状及品质性状指标测定等试验,以无遮阳处理为对照,为光伏农业的甘薯种植提供优异材料。结果表明,在遮阳条件下,3个甘薯品种叶片的叶绿素a和叶绿素b含量总体高于对照(不遮阳)且蔗糖含量均显著降低。遮阳可以增加紫肉型甘薯品种鄂薯12的花青素含量,降低其淀粉、可溶性糖和蔗糖含量;轻度遮阳显著提高了淀粉型甘薯鄂薯15可溶性糖含量且对淀粉含量无较大影响,而重度遮阳显著降低了淀粉型甘薯鄂薯15的淀粉含量;遮阳显著提高了鲜食型甘薯鄂薯17的可溶性糖及淀粉含量。

中国甘薯高效栽培模式及展望

甘薯[Ipomoea batatas(L.)Lam.]是重要的粮食、饲料和工业原料作物。中国是世界上最大的甘薯生产国,其栽培模式具有多样化的特点。对中国甘薯的高效栽培模式进行总结,并对其未来发展进行了展望。中国的甘薯栽培模式以连作和轮作为主,辅以形式多样的间作套种模式。连作和轮作模式便于田间管理,但经济效益较低;间作套种模式能充分利用土地和光温资源、提高复种指数和经济效益,但人工成本较高。各地可根据当地的土壤和气候条件、人力成本及经济目标,因地制宜地选择不同的连作、轮作或间作套种的甘薯栽培模式,或开发推广甘薯栽培新模式。

Different Susceptibility in the Two Sympatric Sweet Potato Weevils, Cylas formicarius and Euscepes postfasciatus, to the Entomopathogenic Fungus Metarhizium anisopliae

Laboratory and field experiments were performed to evaluate the pathogenicity of an isolate of the entomopathogenic fungus Metarhizium anisopliae to the two sympatrically occurring weevil species, Cylas formicarius and Euscepes postfasciatus. In the laboratory bioassays, suspension of conidia, ≥106 CFU/mL, caused mortalities > 80% on adults of both weevils in seven days after inoculation. It took longer time 20 days for grain formulation of the isolate adhered on rice grains of ≥5 g/m2 (107 CFU/g) to attain similar mortalities of E. postfasciatus, but no evident mortality was obtained in C. formicarius. The grain formulation was thus less effective on C. formicarius than the suspension. Field trials were carried out over two years from 2013 to 2014, in which adults of E. postfasciatus were released two times during the field experiments for enhancement of damage on plants by this weevil, whereas the other weevil species was left to naturally invade the experimental plots by flying. The results of the experiments revealed in both years that two applications of the isolate in grain formulation, equivalent to 50 kg/hectare, sprayed manually over the ground surface reduced the infestation of plants and tuber damage by weevils of both species as much as the conventional chemical insecticide applications. The occurrences of weevils at harvest were not significantly different among treatments. The potential and possible uses of the fungus are discussed for the management of these two weevil species.

咸宁市菜用甘薯品种比较试验及品质评价

为筛选出适宜在咸宁市种植的高产、优质的菜用甘薯[Ipomoea batatas(L.)Lam.]品种,对福菜薯7-6(CK)、E8058、鄂菜薯3号、福菜薯18号、福菜薯22号、广菜薯5号、鄂菜薯4号、鄂菜薯10号、鄂菜薯1号、福菜薯23号10个菜用甘薯品种进行栽培试验,综合分析评价菜用甘薯品种的农艺性状、食用品质、生长状况表现、采收产量、营养成分。结果表明,E8058、鄂菜薯1号、广菜薯5号和鄂菜薯4号产量较高,食用品质和营养品质较好,可在咸宁市种植和推广。

不同地膜覆盖对鲜食型甘薯农艺性状和产量的影响

为探讨覆膜栽培对鲜食型甘薯[Ipomoea Batatas(L.)Lam]主要农艺性状和产量的影响,以鲜食型甘薯品种烟薯25为试验材料,研究了不同地膜覆盖对其幼苗移栽成活率、生长发育和薯块产量的影响。结果表明,与CK相比,T1、T3处理的甘薯幼苗移栽成活率均提高了10个百分点左右;覆膜可降低栽后至55 d甘薯的主蔓长、粗和基部分枝数,栽后55 d甘薯茎基部分枝数以T3最多;T3处理甘薯的中薯数量最多,其次是T2,两者分别比CK高83.33%和66.67%。各覆膜处理均能提高甘薯单株薯重,T1、T2和T3分别比CK增加12.36%、31.46%和22.47%。与T2相比,T3可有效降低小薯数量、大薯产量和小薯产量,但增加了中薯数量和产量及其相应的占比。

Plastid Inheritance in Sweet Potato as Revealed by DNA Restriction Fingerprinting

The inheritance of chloroplast DNA (cpDNA) in sweet potato (Ipomoea batatas Lain.) was analyzed using DNA restriction fingerprinting. The cpDNA fingerprints of hybrids from reciprocal crosses between Xushu18 and AB78-1 were found to be identical to those of their female parents, which reveals that cpDNA of sweet potato is maternally inherited in this intervarietal crossing. This maternal cpDNA transmission pattern does not accord with the putative one based on former cytological studies. The plastid inheritance in Convolvulaceae has been briefly reviewed in this study, and the utility of DNA restriction fingerprinting analysis in the study of plastid inheritance is also discussed.

甘薯IbERF071基因的克隆及表达特性分析

为探究甘薯(Ipomoea batatas(L.)Lam.)IbERF071基因在抗蔓割病中的调控作用,根据甘薯转录组数据,从甘薯高抗蔓割病品种‘鄂薯11’中克隆获得1个编码乙烯应答的基因,命名为IbERF071,并对其进行生物信息学分析,以及侵染蔓割病病原菌、外施茉莉酸甲酯和乙烯利的基因表达模式分析。结果表明,IbERF071基因的CDS序列大小为864bp,共编码287个氨基酸;在其编码的氨基酸序列的第79~142位包含1个AP2保守结构域,在第205~254位包含1个卷曲螺旋;IbERF071氨基酸序列与牵牛InERF氨基酸序列的相似度高达89%以上,具有高度同源性,且在系统发育树上也聚为同一支;IbERF071蛋白不稳定指数、脂肪系数和总亲水性平均系数分别为48.26、47.35和-1.003,分子质量为32215.31ku,等电点为5.12,表明该蛋白是一种不稳定的亲水性蛋白质;IbERF071蛋白二级结构中,随机卷曲、α螺旋、延伸链和β转角所占比例分别为61.67%、26.83%、8.01%和3.48%,三级结构中,22%的氨基酸残基结构置信度达到64.06%,IbERF071蛋白定位于细胞核上,没有跨膜蛋白且不存在跨膜螺旋区;IbERF071基因启动子区包含真核生物启动子基本元件胁迫响应元件、茉莉酸甲酯响应元件、低温响应元件MYC、干旱诱导元件ERE、脱落酸效应元件、植物防御响应元件、水杨酸响应元件TCA等30种顺式作用元件;IbERF071基因在根、茎、叶中均有表达,且在根中表达量显著高于茎、叶,经蔓割病原菌侵染后,IbERF071基因的相对表达量显著升高,并在侵染2h时表达量达到峰值,茉莉酸甲酯处理72h和乙烯利处理48h后,其表达量显著提高。综合来看,甘薯IbERF071蛋白属于AP2/ERF超级家族,具有较高的保守性,IbERF071在调控甘薯抗蔓割病菌中的功能以及JA和ET介导的激素信号转导途径的过程中起重要作用。

基于文献计量的甘薯研究发展态势分析

利用文献数据库客观分析全球甘薯[Ipomoea batatas(L.)Lam.]研究现状与发展趋势,以期为甘薯研究工作提供参考。利用Web of ScienceTM核心集数据库,采用文献计量学方法对2009—2018年甘薯研究文献进行统计分析。结果表明,全球甘薯研究论文产出量呈上升趋势,文章质量逐年提高。发文量位列前三的有中国、美国和韩国,美国等发达国家在该领域影响力大,高被引论文大多出自欧美国家。近几年亚洲逐渐成为甘薯研究的新中心,中国的高产活跃作者较多,但距离世界先进水平仍存在一定的差距。美国农业部和中国农业科学院、中国农业大学等机构的甘薯研究论文影响力较大。当前主要研究方向是分子生物学、遗传学和食品科学等方面,学科之间、国家(地区)之间的合作日益紧密。

Cloning and Characterization of a Salt Tolerance-Associated Gene Encoding Trehalose-6-Phosphate Synthase in Sweetpotato

Trehalose plays an important role in metabolic regulation and abiotic stress tolerance in a variety of organisms. In plants, its biosynthesis is catalyzed by two key enzymes： trehalose-6-phosphate synthase（TPS） and trehalose-6-phosphate phosphatase（TPP）. In the present study, a TPS gene, named IbTPS, was first isolated from sweetpotato（Ipomoea batatas（L.） Lam.） cv. Lushu 3 by rapid amplification of cDNA ends（RACE）. The open reading frame（ORF） contained 2 580 nucleotides encoding 859 amino acids with a molecular weight of 97.433 kDa and an isoelectric point（pI） of 5.7. The deduced amino acid sequence showed high identities with TPS of other plants. Real-time quantitative PCR analysis revealed that the expression level of IbTPS gene was significantly higher in stems of Lushu 3 than in its leaves and roots. Subcellular localization analysis in onion epidermal cells indicated that IbTPS gene was located in the nucleus. Transgenic tobacco（cv. Wisconsin 38） plants over-expressing IbTPS gene exhibited significantly higher salt tolerance compared with the control plant. Trehalose and proline content was found to be significantly more accumulated in transgenic tobacco plants than in the wild-type and several stress tolerance related genes were up-regulated. These results suggest that IbTPS gene may enhance salt tolerance of plants by increasing the amount of treahalose and proline and regulating the expression of stress tolerance related genes.