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.

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。

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。

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.

Molecular Cloning and Functional Characterization of a Salt Tolerance-Associated Gene IbNFU1 from Sweetpotato

Iron-sulfur cluster biosynthesis involving the nitrogen fixation（Nif） proteins has been proposed as a general mechanism acting in various organisms.NifU-like protein may play an important role in protecting plants against abiotic and biotic stresses.Based on the EST sequence selected from salt-stressed suppression subtractive hybridization（SSH） cDNA library constructed with a salt-tolerant mutant LM79,a NFU gene,termed IbNFU1,was cloned from sweetpotato（Ipomoea batatas（L.） Lam.） via rapid amplification of cDNA ends（RACE）.The cDNA sequence of 1 117 bp contained an 846 bp open reading frame encoding a 281 amino acids polypeptide with a molecular weight of 30.5 kDa and an isoelectric point（pI） of 5.12.IbNFU1 gene contained a conserved Cys-X-X-Cys motif in C-terminal of the iron-sulfur cluster domain.The deduced amino acid sequence had 66.08 to 71.99% sequence identity to NFU genes reported in Arabidopsis thaliana,Eucalyptus grandis and Vitis vinifera.Real-time quantitative PCR analysis revealed that the expression level of IbNFU1 gene was significantly higher in the roots of the mutant LM79 compared to the wild-type Lizixiang.Transgenic tobacco（cv.Wisconsin 38） plants expressing IbNFU1 gene exhibited significantly higher salt tolerance compared to the untransformed control plants.It is proposed that IbNFU1 gene has an important function for salt tolerance of plants.

Enhanced Stem Nematode Resistance of Transgenic Sweetpotato Plants Expressing Oryzacystatin-I Gene

Enhanced stem nematode resistance of transgenic sweetpotato （cv. Lizixiang） was achieved using Oryzacystatin-I （OCI） gene with Agrobacterium tumefaciens-mediated transformation. A. tumefaciens strain EHA105 harbors a binary vector pCAMBIA1301 with OCI gene, gusA gene and hptII gene. Selection culture was conducted using 25 mg L-1 hygromycin. A total of 1 715 plants were produced from the inoculated 1 450 cell aggregates of Lizixiang via somatic embryogenesis. GUS assay and PCR analysis of the putative transgenic plants randomly sampled showed that 90.54% of them were transgenic plants. Transgenic plants exhibited significantly enhanced resistance to stem nematodes compared to the untransformed control plants by the field evaluation with stem nematodes. Stable integration of the OCI gene into the genome of resistant transgenic plants was confirmed by Southern blot analysis, and the copy number of integrated OCI gene ranged from 1 to 4. Transgene overexpression in stem nematode-resistant plants was demonstrated by quantitative real-time PCR analysis. This study provides a way for improving stem nematode resistance in sweetpotato.

A geranylgeranyl pyrophosphate synthase gene, Ib GGPS, increases carotenoid contents in transgenic sweetpotato

Geranylgeranyl pyrophosphate synthase(GGPS) plays an important role in the biosynthesis of carotenoids. In a previous study, the IbGGPS gene was isolated from a sweetpotato, Ipomoea batatas(L.) Lam., line Nongdafu 14 with high carotenoid contents, but its role and underlying mechanisms in carotenoid biosynthesis in sweetpotato were not investigated. In the present study, the IbGGPS gene was introduced into a sweetpotato cv. Lizixiang and the contents of β-carotene, β-cryptoxanthin, zeaxanthin and lutein were significantly increased in the storage roots of the IbGGPSoverexpressing sweetpotato plants. Further analysis showed that IbGGPS gene overexpression systematically upregulated the genes involved in the glycolytic, 2-C-methyl-D-erythritol-4-phosphate(MEP) and carotenoid pathways,which increased the carotenoid contents in the transgenic plants. These results indicate that the IbGGPS gene has the potential for use in improving the carotenoid contents in sweetpotato and other plants.

Screening of Bacillus subtilis HAAS01 and Its Biocontrol Effect on Fusarium wilt in Sweet Potato

Fusarium wilt,a disease caused by Fusarium oxysporum f.sp batatas(Fob)is an important disease in sweet potato production.Using endophytic bacteria for biological control of sweet potato diseases is one of the important ways.A Bacillus subtilis with antagonistic effect on Fusarium wilt of sweet potato was isolated from soil by confrontation culture.According to the biological characteristics,16S rDNA sequence analysis,and physiological and biochemical analysis,the Bacillus subtilis HAAS01 was named.A pot experiment was conducted for the biological control experiment of strain HAAS01,and the endogenous hormone content,antioxidant enzyme activity,soluble protein content,and related gene expressions of sweet potato plants were detected.The results showed that the HAAS01 strain could promote the production of endogenous hormones and resist the infection of plant diseases together with defensive enzymes and upregulation of related gene expressions.In summary,Bacillus subtilis HAAS01 was effective in controlling Fusarium wilt of sweet potato and has potential for application and development.

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。

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。

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。

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。

紫甘薯新品种比较试验结果分析

通过对金薯17、金薯20、福宁紫4号、福宁紫5号、龙紫4号、龙紫6号、龙紫9号7个优质紫甘薯[Ipomoea batatas(L.)Lam]新品种的产量和性状等进行比较试验,以福宁紫3号为对照,为其在福建省的生产应用提供科学依据。结果表明,龙紫9号产量为46.52 t/hm^2,比对照增产22.4%,居第一位;金薯20也表现了突出的丰产性能,产量达42.35 t/hm^2,比对照增产11.4%,位列各参试品种的第二位;金薯17产量为39.17 t/hm^2,仅比对照增产3.1%;且这3个品种薯块外观好,薯皮紫红色,薯肉紫色,丰产性状好,其中龙紫9号、金薯20产量与对照品种差异达显著或极显著水平,适宜在该地种植推广。其他品种产量都低于对照,其中龙紫6号和龙紫4号与对照品种差异达显著或极显著水平。

武陵山区紫薯引种适宜性分析

为筛选适宜武陵山区种植的紫薯[Ipomoea batatas(L.)Lam)]品种,采用随机区组试验设计,以鄂紫薯1号为对照,对引进的省紫薯、南紫薯008、绵紫薯9号、南紫薯014、南紫薯0155个品种,从农艺性状、鲜薯产量及硒含量等方面进行比较分析。结果表明,在武陵山区气候条件下,绵紫9号、省紫薯、南紫薯0153个品种大中薯率为87.27%~96.15%,鲜薯产量为39151.20~51586.80 kg/hm^(2),与对照差异明显,且硒含量为0.29~0.54 mg/kg,均达富硒标准,初步认定其适宜引入本区域种植。

甘薯淀粉合成相关酶基因的克隆与表达分析

为研究甘薯块根淀粉合成酶基因的表达特征,本研究以淀粉含量不同的两个品种为试验材料,利用转录组数据克隆了甘薯颗粒结合淀粉合成酶GBSS、异淀粉酶ISA、淀粉分支酶SBEⅠ、SBEⅡ的cDNA片段,采用实时荧光定量RT-PCR方法对块根不同生长期淀粉合成相关酶基因的表达进行研究。结果表明,在甘薯不同生长时期,淀粉含量从块根形成期开始逐渐积累,到栽插后80 d、110 d时达到高峰,在块根膨大后期,淀粉含量相对稳定。IbGBSSⅠ、IbSBEⅡ、IbISA 3个基因表达量呈双峰曲线变化,IbSBEⅠ表达呈单峰曲线变化。IbGBSSⅠ、IbISA在栽插后70 d和100 d时表达量达到高峰,IbSBEⅠ在栽插后70 d表达量达到最大。在不同类型甘薯品种中,IbGBSSⅠ在高淀粉品种‘漯徐薯8号’中的表达量显著高于‘郑薯20’,低淀粉品种‘郑薯20’的IbISA表达量显著高于‘漯徐薯8号’。

甘薯优异种质‘浙薯13’及其衍生品种系谱、特征与育种价值分析

以甘薯优异种质‘浙薯13’为亲本,先后衍生出优良新品种27个。本研究对‘浙薯13’及其衍生品种的系谱及主要特征特性进行分析,结果表明‘浙薯13’拥有国内高淀粉核心亲本‘宁薯1号’、地方种质资源‘瑞安红皮红心’和美国引进的高胡萝卜素亲本‘Gem’、优质品种‘南瑞苕’的遗传背景。以‘浙薯13’作母本或父本衍生的品种数分别为20个和7个,均由品种间杂交育成。‘浙薯13’衍生品种的高干物率(干物率>30%)和高淀粉率(淀粉率>20%)比例均超过60%,其中淀粉型、食用型品种和紫薯品种分别占37.0%、22.2%和29.6%。‘浙薯13’衍生品种抗黑斑病、茎线虫病或蔓割病的比例均超过80%,其中抗蔓割病比例达到100%。‘浙薯13’是一个甘薯抗病与品质育种的优良亲本,尤其是在甘薯黑斑病、茎线虫病和蔓割病的抗病育种以及食用紫薯品种选育方面具有较高的利用价值,在长江流域薯区有着广阔的利用前景。‘浙薯13’衍生的多个品种在生产上有较为广泛的应用,发挥了显著地增产增效的作用。因此,注重‘浙薯13’的育种利用以及衍生品种的应用,为今后甘薯新品种遗传改良和应用提供参考。

三种复合侵染‘心香’甘薯的病毒种类鉴定与分析

‘心香’是中国选育的一种优质鲜食早熟甘薯品种。利用小RNA深度测序技术和RT-PCR方法,对采集于海南省东方市1例表现为明显花叶斑驳及叶严重卷曲皱缩症状的‘心香’甘薯叶片进行感染病毒种类鉴定,发现样本中含有马铃薯Y病毒科(Potyviridae)马铃薯Y病毒属(Potyvirus)的甘薯羽状斑驳病毒(sweet potato feathery mottle virus,SPFMV)和甘薯病毒C(sweet potato virus C,SPVC)和乙型线形病毒科(Betaflexiviridae)、麝香石竹潜隐病毒属(Carlavirus)甘薯褪绿斑病毒(sweet potato chlorotic fleck virus,SPCFV)。进一步基于病毒CP基因全长进化树分析结果表明,这3种病毒分离物分属于SPFMV RC株系、SPVCII株系和SPCFV非洲-秘鲁株系组。本研究鉴定出的复合侵染‘心香’甘薯的这三种病毒,将为该品种的病毒防控及脱毒种苗繁育提供理论基础。