西瓜抗枯萎病基因同源序列的克隆与分析

本研究根据已克隆的抗枯萎病基因的NBS保守结构域设计了22条上游简并引物和17条下游简并引物,以西瓜抗枯萎病种质PI296341-FR和感枯萎病品种97103为材料,获得了7条来自基因组DNA的RGA序列（GenBank登录号：DQ156558-DQ156564）,均含有NBS保守区的P-环、kinase-2或kinase-3等抗病基因的特征序列结构,所编码的氨基酸序列与已知抗枯萎病基因Fom-2、I2C-1、I2C-2和I2等编码的氨基酸序列表现出11%～72%的同源性,其中来自PI296341-FR的RGA序列175R1与甜瓜抗枯萎病基因Fom-2的同源性最高,为72%。来自PI296341-FR与97103的RGA序列之间同源性较高（73%～97%）,证明了抗病基因在进化上的保守性。     

大豆抗病基因同源序列的克隆与分析

本研究根据已知抗病基因的NBS保守序列区设计4对简并引物和1对特异引物，以大豆农家种兴县灰布支黑豆为材料，应用PCR方法获得了11条来自基因组DNA的RGA序列和2条来自cDNA的RGA序列，序列长度在500—633bp之间，其中8条来自基因组DNA和2条来自cDNA的RGA序列已在GeneBank登录(登录号为：AF305388—305392，AY008380—008382，AY048863-AY048864)。13条序列都不同程度的含有NBS保守区的P-环(GGVGKTT)、kinase-2(VLDD)、kinase-3(GSRII)及跨膜区GLPL等特征序列结构，由此推导出的氨基酸序列同已知抗病基因L6、RPMl、SRPS2、N编码的氨基酸序列表现出从25％——42％的同源性。本研究克隆的RGA序列根据其相似性可分为4组，与已发表的大豆抗病类似基因(RLG)具有较高的相似性。     

小麦抗病基因同源序列(RGAs)的克隆与分析

RGA(抗性基因同源序列)法是克隆植物抗性基因的一种经济有效的方法,成为近年来的研究热点。本实验综合分析了拟南芥,西红柿,水稻,烟草等植物已克隆的抗性基因,并以这些抗性基因的NBS(核酸结合位点),LRR(富含亮氨酸重复),STK(丝氨酸/苏氨酸激酶)保守结构域设计并合成了几十对RGA引物,对小麦抗条锈病材料进行PCR扩增,获得以Xal-NBS为引物的R88RGA片段,经克隆和序列比对分析,发现该片段与逆境条件下植物抗病信号传导相关,与蛋白激酶同源性达到96%。此项研究对抗病机理的研究和基因的发掘有重要的指导意义。     

利用中间偃麦草抗病基因同源序列分离黄矮病抗性候选基因克隆

根据已克隆植物抗病（R）基因编码蛋白质的保守结构设计简并引物,利用同源序列法PCR扩增、克隆到9个具有开放阅读框的中间偃麦草R基因同源片段（Resistance Gene Analogs,RGAs）。利用抗黄矮病材料(含Bdv2)、感黄矮病材料（无Bdv2）进行RFLP分析,筛选到1个NBS类RGA序列TirgaZ1与Bdv2连锁。根据TirgaZ1的序列重新设计1对引     

基于生物信息学的玉米抗病QTL比较定位

以玉米遗传连锁图谱IBM2 2008 Neighbors为参考图谱,利用BioMercator 2.1软件,通过映射来自不同实验中的340个玉米抗病QTL,构建出玉米抗病QTL的整合图谱。采用元分析技术,在1、3、6、10号染色体上发掘5个"一致性抗病QTL"区间,图距分别为5.14cM、9.00cM、28.50cM、1.73cM和33.34cM。从MaizeGDB网站下载"一致性抗病QTL"区间内的基因和标记原始序列,采用NCBI网站在线软件BlastX通过同源比对,在5个"一致性抗病QTL"区间内初步确定8个抗病基因同源序列。借助比较基因电子定位策略,将54个水稻和44个玉米抗性基因转定于玉米IBM2 2008 Neighbors遗传连锁图谱上。本文研究结果为玉米抗病QTL精细定位和克隆奠定了基础。     

小麦抗白粉病基因Pm43定位区段内RGA分析

利用普通小麦测序草图可从基因组范围内对小麦单条染色体上的某个区段进行分析。Pm43是作物遗传与分子改良山西省重点实验室在小麦2D染色体长臂上定位的一个抗白粉病基因。利用信息学方法分析Pm43所在物理图谱、遗传图谱和基因组图谱上的位置,可为其精细定位乃至候选基因的确定提供参考。试验采用Pm43两侧标记序列进行比对,将Pm43定位于染色体C-2DL3-0.49区间的79~99 c M内,所在基因组区段为2DL_9835990~2DL_9823315。利用目前已克隆小麦抗病基因的保守基序作为探针,从目标区段内检索出89条包含抗病基因类似物(Resistance gene analogues,RGA)序列的scaffold,其中,36条scaffold被诊断出含有SSR位点,之后针对SSR位点开发分子标记。利用携带有Pm43的普通小麦材料CH5025、感白粉病材料台长29以及CH5025×台长29的F2作图群体的抗感池DNA,对开发的SSR标记进行连锁性检测,共筛选出4个多态性标记,从而将目标区段进一步确定在标记PK_9908430和NBS_9908778之间。最后经聚类分析,筛选出与已克隆Pm基因同源性较高的1个PK序列和1个NBS序列,且在粗山羊草2D染色体和水稻第4染色体中均存在与这2个序列同源的RGA表达序列。     

植物抗病基因同源序列(RGA)研究进展

目前已克隆了48个植物抗病（R)基因,其表达产物在不同的物种具有典型的保守结构区域,按其序列的同源性可以将其归为NBS-LRR、eLRR、LRR-STK等几个超家族。根据这些保守序列设计合适的引物进行PCR扩增,即得到抗病基因同源序列(RGA)。对RGA与R基因关系的分析表明,RGA不仅在抗病基因定位和抗病基因系统进化研究中有重要作用,而且有可能为克隆尺基因提供一条崭新而又便捷的途径。     

大豆种粒斑驳抗性的遗传分析及基因定位

运用SSR标记技术及分离群体组群分析法(BSA法), 对大豆品系3C624×东农8143的F₂、F₃代群体接种SMV1号株系鉴定种粒斑驳抗性, 并进行抗种粒斑驳基因的分子定位。结果表明, 东农8143对SMV1号株系的种粒斑驳抗性受1对显性基因控制。用Mapmaker/Exp 3.0b进行连锁分析, 抗种粒斑驳基因位于大豆染色体组的F连锁群上, 并获得了与抗种粒斑驳基因紧密连锁的5个SSR标记Sat_297、Sat_229、Sat_317、Satt335和Sct_188, 标记与抗病基因间的排列顺序和连锁距离为Sat_297–12.4 cM–Sat_229–3.6 cM–SRSMV1–1.7 cM–Sat_317–2.4 cM– Satt335–13.8 cM–Sct_188。其中近距离标记Sat_229(3.6 cM)、Sat_317(1.7 cM)和Satt335(4.1 cM)可用于标记辅助选择育种和抗源筛选。     

小麦抗叶锈病基因Lr35的RGA分析

根据已知植物抗病基因的NBS,LRR等保守结构域设计引物,对小麦全套抗叶锈病近等基因系材料进行RGA分析。引物对Pto-kin1IN／XLRR-INV1从近等基因系TeLr35中扩增获得一条747bp的特异性片段。序列分析表明,该片段与小麦基因片段Triticum urartu clone BAC 210J24,Triticum monococcum DV92的BAC克隆231A16等具有较高同源性,为Lr35的克隆奠定了基础。     

利用同源序列发掘抗病候选基因的方法

抗病基因的分离和克隆对于实施作物抗病基因育种及开展抗病机制的研究具有重要意义。目前植物抗病基因的克隆方法主要有转座子标签技术和图位克隆技术。该法对于未知基因产物或者没有进行精细定位的性状来讲，其应用受到极大限制。近年来，很多研究探索了利用同源序列发掘抗病候选基因的途径。本研究归纳和总结了三条发掘抗病候选基因的方法，旨在对作物抗病基因及其连锁标记的发掘起到一定的指导作用。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.