小麦-华山新麦草7Ns异附加系的分子细胞遗传学研究

为了给有效利用华山新麦草基因提供新的种质材料,利用细胞遗传学、分子标记等技术,结合田间农艺性状考察,对从小麦-华山新麦草七倍体材料H8911-99与硬粒小麦D4286杂交F4代分离群体中选育的杂交后代12DH25进行了鉴定。华山新麦草基因组特异SCAR标记鉴定表明,12DH25含有华山新麦草遗传物质;有丝分裂和花粉母细胞减数分裂中期I染色体数为2n=44=22Ⅱ,基因组原位杂交(GISH)出现两条杂交信号,且能配对,表明两条外源染色体是华山新麦草的一对同源染色体。选取定位于小麦7个部分同源群上的28对STS标记对12DH25及其亲本基因组DNA进行扩增,定位于小麦第7同源群上的STS标记BE591127和BG274576能在12DH25中扩增出华山新麦草特征条带,将12DH25附加的华山新麦草染色体归属于小麦第7部分同源群。由此确定矮秆材料12DH25是一个稳定的小麦-华山新麦草7Ns二体异附加系。     

普通小麦 华山新麦草衍生后代H18和0841的SSR标记鉴定

为了明确普通小麦华山新麦草衍生后代材料中所携带的外源遗传物质,利用SSR标记对普通小麦-华山新麦草衍生后代H18和0841进行了鉴定.SSR标记结果表明,331个SSR标记中有271个在亲本华山新麦草和普通小麦7182间具有多态性;85个在华山新麦草中具有清晰且明亮的特异条带,其中9个标记在H18衍生的8个单株中(2n=51～54)具有华山新麦草特征条带.0841的染色体数目为42条,利用筛选的9个标记对其鉴定,发现定位于小麦3D染色体上的标记Xbarc71在0841中具有华山新麦草的特异条带,同时缺失小麦亲本7182的特异条带,推测0841可能是华山新麦草的3Ns染色体代换了小麦的3D染色体.条锈病抗性鉴定显示,0841中抗至高抗条锈菌条中31号和条中32号混合小种.     

小麦-华山新麦草异附加系的细胞遗传学和分子标记辅助鉴定

华山新麦草(2n=2x=14,NsNs)含多种优良基因,是一类具有广阔应用前景的育种资源。为给小麦育种培育新材料,本研究对来自普通小麦品系7182和华山新麦草的高代衍生系H1133、H4122和H1423进行细胞遗传学和分子标记辅助鉴定。细胞学观察表明,3个衍生系的染色体数和构型均为2n=44=22Ⅱ;基因组原位杂交(GISH)和荧光原位杂交(FISH)同步分析结果表明,3个衍生系均含42条普通小麦染色体和2条华山新麦草Ns染色体;EST和PLUG标记分析证明H1133、H4122和H1423中附加的分别为华山新麦草3Ns、5Ns和7Ns染色体,说明H1133、H4122和H1423分别为小麦-华山新麦草的3Ns附加系、5Ns附加系和7Ns附加系;形态学鉴定结果表明,三个附加系与亲本7182在株高、分蘖和穗长等农艺性状上表现出不同差异;成株期抗条锈病鉴定结果表明,H4122和H1423高抗CYR32和CYR33混合菌种,从材料系谱推断其抗性来源于华山新麦草。总之,附加系H1133、H4122和H1423在农艺性状和抗病性上均有良好表现,可作为小麦育种中的桥梁材料。     

小麦-华山新麦草易位系24-6的鉴定

为给小麦-华山新麦草远缘杂交育种提供材料和理论基础,对普通小麦与华山新麦草杂交后代中选育出的材料24-6进行了形态学观察、细胞学检测和原位杂交(GISH)分析。结果表明:(1)通过根尖细胞学鉴定,该材料染色体数为42条,2n=42;(2)以华山新麦草Ns基因组DNA为探针,普通小麦7182基因组DNA为封阻,根尖与花粉母细胞原位杂交(GISH)显示该材料携带有2条可以配对的华山新麦草染色体臂,确定24-6为稳定的小麦-华山新麦草易位系;(3)田间观察发现24-6植株紧凑,叶色深绿,籽粒白色、呈半角质,比其母本(普通小麦7182)株高略有降低,穗长、小穗数、穗粒数、千粒重、分蘖数都有所增加。     

华山新麦草2Ns染色体SCAR标记的开发

为准确快速地建立小麦-华山新麦草杂交后代的分子标记鉴定方法,利用180条长度为10 bp的随机引物R1~R180对小麦-华山新麦草全套（1Ns~7Ns）二体附加系及其亲本华山新麦草和普通小麦7182共9个材料进行了RAPD分析。结果表明,R131在华山新麦草和小麦-华山新麦草2Ns二体附加系中可以扩增出特异条带。将该特异条带回收并测序,发现其全长为1 126 bp,对其进行序列比对分析后设计SCAR引物S131,然后利用S131重新对9份材料进行了SCAR分析。结果显示,S131只在华山新麦草和小麦-华山新麦草2Ns二体附加系中扩增出特异性条带,表明RAPD标记R131已成功转化为可靠、特异的SCAR标记S131。这个新的SCAR标记可用于检测普通小麦背景下华山新麦草2Ns染色体。     

三个小麦-华山新麦草二体附加系分子细胞遗传学的初步鉴定

华山新麦草是我国华山地区特有小麦近缘物种，具有抗逆、早熟、优质等特点，对小麦的白粉病、条锈病、赤霉病也具有良好的抗性，是小麦重要的三级基因库。为进一步更好地发挥华山新麦草基因资源的作用，本研究利用细胞学方法、原位杂交技术、分子标记技术、农艺性状评估和抗病性鉴定对普通小麦-华山新麦草衍生后代材料进行鉴定，并获得了 20H11、17H21、18H28 三个小麦-华山新麦草衍生系。结果表明，20H11、17H21 和 18H28 的染色体数都是 44 条，均携带2 条属于华山新麦草的 Ns 染色体和 42 条普通小麦染色体。利用华山新麦草的特异分子标记进行检测，证明 20H11、17H21 和 18H28分别为 3Ns、4Ns和 2Ns二体附加系。通过农艺性状调查，3个试验异染色体系与亲本7182相比，株高和小穗粒数的差异不显著；分蘖数目与亲本7182有显著差异；20H11的穗长显著短于亲本7182；17H21的分蘖数显著少于亲本7182。经条锈病抗性鉴定，18H28 高抗条锈病小种 CYR32 和 CYR34。因此，这三个华山新麦草衍生系可作为中间材料用于小麦遗传育种研究。     

华山新麦草3Ns染色体特异SCAR标记的开发

为快速准确地建立小麦-华山新麦草杂交后代的分子标记鉴定方法,采用150条10bp的随机引物R1-R150对华山新麦草、普通小麦7182、中国春及华山新麦草1Ns-7Ns全套二体附加系共10个材料进行了RAPD分析,从中获得了华山新麦草3Ns染色体上2个特异RAPD分子标记片段FR-113和FR-125。克隆这两个片段并测序,发现其全长分别为543bp和515bp;分析序列后对其分别设计SCAR引物S-113和S-125,重新对10个材料进行SCAR分析,结果只在华山新麦草和小麦-华山新麦草3Ns二体附加系上扩增出了特异条带,由此证明已将华山新麦草3Ns染色体上获得的两个RAPD标记成功转化为稳定可靠的SCAR标记。这两个SCAR标记可用于检测小麦背景下的华山新麦草3Ns染色体,同时为小麦-华山新麦草杂交后代提供了分子鉴定依据。     

华山新麦草特异重复序列的筛选、克隆及Southern杂交分析

为了寻找华山新麦草特异重复序列,以华山新麦草、栽培一粒小麦、栽培二粒小麦、野生一粒小麦、野生二粒小麦、圆锥小麦、阿拉拉特小麦、茹科夫斯基小麦、斯卑尔脱小麦、普通小麦"中国春"(CS)为材料,利用200条RAPD引物筛选出11条华山新麦草特异条带(命名为RHS1~RHS11),并对这些条带进行回收、克隆、测序。将序列在NCBI数据库中进行比对,其中RHS1、RHS2、RHS3、RHS4、RHS6、RHS8、RHS9在NCBI数据库中未发现与其同源的序列。RHS5、RHS7、RHS10、RHS11在NCBI数据库中有相似序列,其最高覆盖度和最高相似性分别为:83%和100%、99%和85%、49%和100%、19%和83%。通过Southern blotting进行序列特异性检测,RHS1、RHS2、RHS4、RHS6和RHS9等5个克隆在10种材料中都没有杂交信号;RHS7、RHS10和RHS11在华山新麦草及其他9种材料中都有弥散分布的杂交信号;RHS3、RHS5和RHS8只在华山新麦草中有杂交信号的序列。这些结果说明RHS3、RHS5、RHS8为华山新麦草基因组特异重复序列。     

基于TRAP的长穗偃麦草SCAR标记的开发及应用

为了开发长穗偃麦草的特异标记,依据TRAP技术,利用56对固定引物与随机引物的组合对中国春-长穗偃麦草附加系等材料进行PCR扩增,共筛选出160条分布于长穗偃麦草1E-7E染色体的特异扩增片段。通过对104个片段的序列进行同源比对,选择与小麦无同源序列的区段设计138对引物,分别对中国春、长穗偃麦草、中国春-长穗偃麦草附加系进行PCR扩增,最终获得30个长穗偃麦草特异SCAR标记,发展标记的效率为53.6%。利用这些特异SCAR标记对硬粒小麦(AABB)与异源六倍体小麦(AABBEE)杂交产生的F2中38个单株进行扩增鉴定,9个单株仅附加了1条相同的E染色体,其余为多条E染色体或者无E染色体附加。这些SCAR标记在不同材料和世代表现出优越的特异性和稳定性,可用于检测小麦背景中附加的相关长穗偃麦草染色体。     

普通小麦-华山新麦草衍生后代的细胞学特点及GISH分析

为了研究华山新麦草染色体在小麦-华山新麦草各衍生世代中的遗传规律并建立一套小麦-华山新麦草异源附加系,对小麦-华山新麦草BC1F2到BC1F5共315个植株进行细胞学检测和GISH分析,结果表明,染色体数目分布范围为40～54,2n≥43的植株有223株,占总观察株数的70.79%;早代植株携带华山新麦草染色体的概率较高,植株染色体数目多大于44,随着自交代数的增加,外源染色体丢失的概率也在增大.因而在选育小麦-华山新麦草异附加系时,在BC1F4和BC1F5世代选择效果较好;通过对染色体数目2n=44的42个植株进行GISH分析,筛选出39个二体附加植株.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

先玉335、郑单958和京科968抗虫能力的比较研究

以先玉335、郑单958、京科968为材料,以玉米螟(Ostrinia furnacalis)、黏虫(Mythimna separata)和禾谷缢管蚜(Rhopalosiphum padi)为供试昆虫,探究玉米品系大喇叭口期对玉米螟和黏虫及抽雄期对禾谷缢管蚜抗性差异,测定其主要抗虫化合物丁布类物质的含量。结果发现,京科968对玉米螟及禾谷缢管蚜抗性均高于另外两个品系;对黏虫的抗性,郑单958和京科968高于先玉335。大喇叭口期京科968中丁布类物质含量最高,抽雄期郑单958和京科968中主要丁布成分含量均高于先玉335,上述组织中丁布合成相关基因在郑单958及京科968中的表达量也均高于先玉335。本研究揭示杂交玉米抗虫性与抗性相关化合物含量及其相关基因表达间存在正向相关关系,为抗虫玉米分子育种提供理论参考。     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

小麦株高QTL的定位及对重要农艺性状的多效性分析

株高作为小麦育种的重要指标,对产量具有较大的影响。为进一步挖掘小麦株高的数量性状位点（quantitative trait loci,QTL）,本研究以扬麦12和偃展1号杂交得到的包含205个家系的重组自交系（recombinant inbred lines,RIL）群体为材料,利用小麦55K SNP芯片构建高密度遗传图谱,结合 3年共6个环境的表型数据对株高性状进行QTL定位分析。结果表明,在染色体2B（1）、4B（1）、4D（1）、5A（1）、5B（1）和7D（2）上共检测到7个与株高相关的QTL。QPh.yaas-4B、QPh.yaas-5A和QPh.yaas-7D.1的矮秆效应来源于扬麦12,其余4个QTL的矮秆效应来源于偃展1号。在6个环境下都能检测到的位点是QPh.yaas-4B和QPh.yaas-4D,对株高的贡献率分别14.50%~24.09%和19.01%~29.80%,经过比对发现,这2个QTL分别是Rht1和Rht2。QPh.yaas-5A在5个环境下被检测到,对株高的贡献率为3.29%~5.36%;QPh.yaas-2D和QPh.yaas-7D.2在4个环境中均被检测到,对株高的贡献率分别为3.45%~6.14%和3.16%~4.10%;QPh.yaas-5B和QPh.yaas-7D.1分别在2个和3个环境中被检测到,对株高的贡献率分别是2.27%~5.09%和2.72%~4.82%。QTL比较分析后发现,QPh.yaas-7D.1和QPh.yaas-7D.2可能是新的株高位点。研究Rht-B1和Rht-D1对千粒重、穗长和穗粒数的效应,发现Rht-B1位点对这些农艺性状无显著效应,Rht-D1位点仅对千粒重有显著效应,其株高增效等位变异可显著增加千粒重。在自然群体中验证Rht-B1和Rht-D1的效应结果与RIL群体结果一致。     

分子标记辅助小麦抗白粉病基因Pm21和Pm13聚合育种

为了获得同时具有抗白粉病基因Pm21和Pm13的材料,利用与抗白粉病基因Pm21和Pm13共分离或紧密连锁的分子标记SCAR1400、CINAU161650和SCAR564、BE398268,对分别含Pm21和Pm13的小麦品系杂交F2代进行检测。结果表明,在764个F2代单株中,能同时检测到显性标记SCAR1400和SCAR564的有404株,阳性率为52.9%,经标记CINAU161650和BE398268检测,同时携带纯合Pm21和Pm13的单株有47株,阳性率为6.15%,两个显性抗病基因在F2代群体中的分离比例符合孟德尔独立分配定律。获得的聚合单株可作为小麦抗白粉病育种的亲本资源。     

Resistance to <Emphasis Type="Italic">Potato virus Y</Emphasis> in a Multitrait Potato Breeding Scheme without Direct Selection in Each Generation

In an experimental breeding scheme to improve late blight (Phytophthora infestans) and white potato cyst nematode (Globodera pallida) resistance of tetraploid potato over three generations of crossing and selection, 15 clones survived the final selection, and these were derived from 15 great-grandparents. There was no direct selection for resistance to Potato virus Y (PVY), but 14 out of the 15 great-grandparents were resistant to PVY and three had extreme resistance. Thirteen of the 15 descendants had PVY resistance and one extreme resistance. This was within the range expected for a random (unselected) sample from the genotypes of the great-grandparents. Hence, we found no evidence for any positive or negative association between PVY resistance and the attributes selected. The conclusion is that laborious selection is not required in every generation when many parents have PVY resistance, including some with more than one copy of a PVY resistance gene or resistance at more than one locus. However, in the future, determining the major virus resistance genes present in potential parents in each generation using diagnostic molecular markers would prevent susceptible × susceptible crosses being made and maximise the number of resistant × resistant ones.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

华山新麦草穗发芽抗性相关基因AIP2的克隆及其序列分析

为了挖掘和利用华山新麦草(Psathyrostachys huashanica,2n=14,NsNs)的优良基因,拓宽小麦穗发芽抗性基因资源,以华山新麦草为材料,采用同源克隆的方法克隆AIP2基因,利用生物信息学软件分析其基因结构及功能。结果表明,从华山新麦草中成功克隆AIP2基因,该基因的开放阅读框为840bp,编码279个氨基酸残基,结构域预测结果显示AIP2蛋白含有完整的Ring保守域,属于锌指环家族成员。AIP2的gDNA含5个外显子,4个内含子,华山新麦草AIP2氨基酸序列与感穗发芽小麦品种中优9507的AIP2氨基酸序列的相似性为84%,与中优9507相比缺失了44个氨基酸,与抗穗发芽的乌拉尔图小麦的AIP2氨基酸序列的相似性为80%,华山新麦草和乌拉尔图小麦都有氨基酸缺失,推测这些缺失的氨基酸可能与华山新麦草穗发芽抗性强有很大关系。本研究为小麦穗发芽抗性改良提供了新的候选基因。