谷子与轮生狗尾草（2X,4X）种间的亲缘关系分析

将同工酶技术与细胞遗传学相结合,对谷子与轮生狗尾草（２Ｘ、４Ｘ）野生种之间的遗传与进化关系进行了分析。分析结果表明：谷子与轮生狗尾草四倍体类型（４Ｘ）具有一定的同源性,而与轮生狗尾草二倍体类型（２Ｘ）的同源性较少。轮生狗尾草四倍体类型与轮生狗尾草二倍体类型具有与谷子相近的同淅性。青狗尾草（谷子）和轮生狗尾草二倍体类型（２Ｘ）是轮生狗尾草四倍体类型（４Ｘ）最可能的两个祖先种。轮生狗尾草二倍体类型与四     

中国谷子主产区谷子近缘种狗尾草的遗传多样性

用同工酶淀粉凝胶电泳技术分析了在中国北方谷子主产区采集与收集的谷子、谷子近缘野生种青狗尾草(包括谷莠子)和金狗尾草的代表群体。分析了12种等位酶(AAT、ADH、AMP、DIA、GDH、IDH、MDH、ME、PGD、GPI、PGM、SKD)的21个等位酶位点的数据。结果表明：青狗尾草同其它以自花授粉为主的一年生植物相比表现更高的遗传变异性。AAT—3、PGD、PGM在所有供试材料中均表现单态,而在金狗尾草中缺失(沉默)IDH-l。不同地理来源的青狗尾草同谷子的亲缘关系存在一定的差异,而且青狗尾草间的遗传差异同地理区域相关。本研究结果支持把谷子和青狗尾草划为一个种的观点。     

六个不同类型荞麦花花粉粒形态的电镜观察比较研究

对二倍体甜荞长花柱类型 (ES2 s)、二倍体甜荞短花柱类型 (ES2 S)、四倍体甜荞长花柱类型 (ES4s)、四倍体甜荞短花柱类型 (ES4S)、四倍体有翅细野荞 (GR4HI)、四倍体无翅细野荞 (GR4HO)等 6个不同荞麦类型花的花粉形态学进行了电镜观察。结果表明 :这些荞麦类型的花粉粒都是椭圆形 ,都有网状纹饰、3孔沟等特征。二倍体甜荞染色体加倍后形成的四倍体甜荞 ,相对于二倍体甜荞而言 ,花粉粒显著增大和明显变圆。无论二倍体还是四倍体甜荞 ,其长花柱型花的花粉粒都比其对应短花柱型花的花粉粒要小。尽管四倍体甜荞和四倍体细野荞在染色体数目和倍性上一样 ,但是它们在花粉粒的大小上有显著差异。四倍体细野荞有翅类型和无翅类型的花粉粒大小和形态差异不显著     

亚比棉基因组原位杂交及核型分析

亚比棉异源四倍体是山西农业大学棉花育种组于上个世纪80年代用A染色体组亚洲棉(Gossypium.arboreum)(迁西小黑籽)与G染色体组野生棉比克氏棉(G.bickii)杂交成异源二倍体后,又经过加倍而获得的.亚比棉异源四倍体不仅育性得到恢复、结铃正常,而且成功地将比克氏棉的优异性状--种子腺体延缓形成转育到亚比棉中.这为实现棉花综合利用和提高抗虫性创育了新的育种材料.在随后的多年中,山西农业大学棉花育种组对亚比棉异源四倍体进行了广泛的细胞形态学研究,对其核型做了分析.然而,仅依据形态学和普通的核型图像,还不能确定该异源四倍体棉种中比克氏棉G染色体(亚)组在核型中的表现.该文以比克氏棉gDNA为探针,亚比棉异源四倍体根尖体细胞染色体为靶细胞染色体,封阻材料为亚洲棉(迁西小黑籽),进行亚比棉基因组原位杂交(Genome in situ hybridization,GISH)及核型分析.从获得的图像中可以清晰地发现有52条染色体,其中有/无杂交信号的各一半,这直观地证实了人工复合亚比棉杂交种确为异源四倍体,而且是双二倍体.A亚组与G亚组染色体长度存在交替排列.亚比棉异源四倍体基于GISH图像的核型公式为2n=4x=52=46m(4sat)+6sm(4sat).A亚组和G亚组染色体上各有2对随体.G亚组染色体中至少有5对双重显色明显的染色体,意味着可能有A亚组染色体的交换,而A亚组染色体中只观察到或多或少的探针红色荧光信号,由于分辨率不够而难于定量分析.进一步以45SrDNA为探针,以鲑鱼精DNA作为封阻DNA,对亚比棉异源四倍体进行45SrDNA-FISH,实验表明,亚比棉异源四倍体有14个NOR(核仁组织区)信号,说明亚比棉异源四倍体有14个随体,即7对随体.比克氏棉对亚洲棉的GISH结果显示,在有亚洲棉DNA封阻的条件下,亚洲棉靶细胞染色体无任何杂交信号,说明比克氏棉与亚洲棉染色体之间不存在较大的同源或相似序列.     

荞麦野生种的核型及进化特征分析

荞麦起源于我国西南地区,该地区分布着丰富的荞麦野生种,剖析野生荞麦的核型特征对荞麦进化和育种研究具有重要的意义。本研究以甜荞近缘种、硬枝万年荞、疏穗小野荞、细柄野荞、齿翅野荞为试验材料,采用常规压片法进行核型鉴定。结果表明:甜荞近缘种、硬枝万年荞和疏穗小野荞都为二倍体,核型公式分别为2n=2x=16=12M+4m(2SAT)、2n=2x=16=16M、2n=2x=16=14M+2m(2SAT),而细柄野荞和齿翅野荞为四倍体,核型公式分别为2n=4x=32=32M、2n=4x=32=30M+2m(2SAT)。甜荞近缘种和硬枝万年荞核型属1A型,疏穗小野荞、细柄野荞和齿翅野荞核型属1B型,并且甜荞近缘种、疏穗小野荞和齿翅野荞都有1对随体染色体。研究证明,荞麦野生种染色体的基数为8,有二倍体和四倍体野生荞麦。通过比较分析,硬枝万年荞在进化地位上比较原始,齿翅野荞是比细柄野荞较进化的四倍体荞麦野生种。     

云南山茶花四倍体的首次发现及其科学意义

本文对分布于云南和四川金沙江河谷的云南山茶花C. reticulata及其两个近缘种(怒江山茶C.saluenensis和西南山茶C．pitardii)进行了细胞学研究。34个居群的云南山茶花中,21个居群是四倍体类型(2n=60),11个居群是六倍体类型(2n=90),另2个居群为二倍体(2n=30),云南山茶花的四倍体类型为首次发现,并且进行了核形态研究。四倍体和六倍体的花粉母细胞减数分裂染色体构型在大多数居群都为二价体(四倍体中30个二价体,六倍体中45个二价体),少数居群或是个体除二价体为主外还出现单价体和四价体,六倍体类型没有出现六价体构型。根据减数分裂的构型,我们认为,四倍体和六倍体分别为异源四倍体和异源六倍体,少数四价体的存在表明染色体有部分同源性。所有四倍体和六倍体的体细胞间期核特征和前期染色体形态特征基本相似。中海拔(1800m)以上的四倍体的云南山茶花外部形态特征与六倍体类型比较相似,而低海拔(1100～1800 m)的四倍体类型的外部形态特征则有些不同,但核形态结构是比较相似的。四倍体与六倍体类型地理分布是连续的,并与近缘的二倍体种怒江山茶、西南山茶重叠分布。     

谷子(Setaria italica(L.) P. Beauv.)作为功能基因组研究模式植物的发展现状及趋势

模式植物对遗传学和分子生物学前沿理论探索和实践研究至关重要。玉米、拟南芥和水稻等主要的模式植物,在植物遗传学发展的不同时期发挥了不可替代的作用,但随着研究的深入和细化,迫切需要更多别具特色的物种成为模式植物。谷子(Setaria italia)及其野生种青狗尾草(S.viridis)因具备C_4光合途径和特殊的抗旱耐逆性备受关注,谷子也因其较小的二倍体基因组、自花授粉、高繁殖系数、较小的株高和易于操作的栽培方法,以及生育周期短、易于快速繁殖等特点,非常适合作为分子遗传学研究的模式植物,近年来作为C4和抗旱耐逆研究的模式系统越来越受到国际植物遗传学界的关注。谷子是起源于中国的古老农作物,我国拥有最丰富的遗传资源,并在遗传育种研究上处于领先。现简述我国谷子的研究基础,综述近年来谷子和青狗尾草作为模式作物的研究进展,讨论相关研究存在的问题,并对谷子遗传研究的发展趋势进行展望。     

四倍体长穗偃麦草(Agropyron elongatum 4x)染色体组构成的生化和SSR标记分析

应用等电聚焦(IEF)和SDS PAGE方法分析了二倍体长穗偃麦草(Agropyronelongatum2x)和四倍体长穗偃麦草(Ag.elongatum4x)的16种同工酶和3种贮藏蛋白的电泳图谱。结果表明,只有两种同工酶在四倍体和二倍体长穗偃麦草之间表现相同的酶谱,该类型仅占分析标记总数的10.5%;而10种同工酶和3种贮藏蛋白的电泳图谱在四倍体中除了具有全部二倍体的谱带以外,还有自己独特的条带,该类型最多,占分析标记总数的63.2%;另外5种同工酶在二倍体和四倍体之间只有部分条带相同,同时具有各自特异的条带,该类型占分析标记总数的26.3%。由此推测,四倍体长穗偃麦草可能是一个异源四倍体,即只含有一个起源于二倍体类型的染色体组Ee,而另一个染色体组在所分析的生化标记上明显不同于近缘种中的St、J和N染色体组,其起源尚待进一步研究。进一步用小麦的SSR引物对二倍体和四倍体长穗偃麦草进行扩增,结果表明大多数SSR引物在四倍体中既能扩出与二倍体相同的条带,同时还有其特异的条带,这一结果验证了由生化标记得出的四倍体长穗偃麦草是异源四倍体的初步结论。     

17种金线Ba核DNA含量及倍性的研究

采用血涂自、Feulgen染色和显微分光光度技术,测定了金线Ba属（Sinocyclocheilus）17个种的核DNA含量。结果显示,除侧条金线Ba(S.lateristritus）中采自云南沾益炎方山那边的样本之2C值为7.79 pg外,其余的核DNA 2C值都集中分布在4.19-4.86pg范围,大体与其近缘四倍体种2C值相同或相近,是其近缘二倍体种2C值的大约2倍 此我们推断,这17种金线Ba很有都是四倍体,个别种还含有八倍体的类型,金线Ba属可能是整属的四倍体起源。     

中国17种蔷薇属植物45S和5S的rDNA分布研究

为了探寻蔷薇属植物亲缘关系及系统发育研究的分子细胞遗传学证据,该研究采用双色FISH(荧光原位杂交)技术,对原产中国7个组的17种蔷薇属植物的45S和5S rDNA进行了定位分析。结果表明:(1)多数蔷薇属植物1组染色体对应1个45S rDNA位点和1个或2个5S rDNA位点,偶尔出现1~2个rDNA位点的丢失,但复伞房蔷薇(Rosa brunonii)的1组染色体对应了2个45S rDNA位点。(2)二倍体的蔷薇属植物至少有1对5S rDNA位点与45S rDNA位点共定位,而四倍体材料的5S rDNA位点与45S rDNA位点没有共定位,但所有四倍体材料均至少有1种rDNA信号纯合,表明它们应为二倍体直接加倍产生的同源四倍体。(3)绝大多数材料45S rDNA位于染色体短臂、5S rDNA位于染色体长臂,但缫丝花(R. roxburghii f. roxburghii)有1个5S rDNA信号位于染色体的短臂上,表明它与蔷薇属其他种的亲缘关系较远。(4)阿克苏地区和伊犁地区的疏花蔷薇的核型不同,且45S和5S rDNA的数量和位置不同,分子细胞遗传学证据也支持阿克苏地区的疏花蔷薇应为疏花蔷薇的新变种。(5)该研究中共有8个二倍体和6个四倍体蔷薇属植物的双色FISH为首次报道。研究认为,无论二倍体还是四倍体蔷薇属植物中出现的异形同源染色体、rDNA信号位置在同源染色体上的差异以及rDNA信号的增加和丢失,可能都与染色体结构变异和染色体重组有关,在分子细胞遗传学水平上证明染色体结构变异和染色体重组在蔷薇属植物演化过程中具有重要的作用。     

Genomic in situ hybridization (GISH) discriminates between the A and the B genomes in diploid and tetraploid Setaria species.

Genomic in situ hybridization (GISH) was used to investigate genomic relationships between different Setaria species of the foxtail millet gene pool (S. italica) and one interspecific F1 hybrid. The GISH patterns obtained on the two diploid species S. viridis (genome A) and S. adhaerans (genome B), and on their F1 hybrid showed clear differentiation between these two genomes except at the nucleolar organizing regions. Similar GISH patterns allowed differentiation of S. italica from S. adhaerans. However, GISH patterns did not distinguish between the genomes of S. italica and its putative wild ancestor S. viridis. GISH was also applied to polyploid Setaria species and enabled confirmation of the assumed allotetraploid nature of S. faberii and demonstration that both S. verticillata and S. verticillata var. ambigua were also allotetraploids. All these tetraploid species contained two sets of 18 chromosomes each, one from genome A and the other from genome B. Only one polyploid species, S. pumila, was shown to bear an unknown genomic composition that is not closely related either to genome A or to genome B.     

Variation of microsatellites BM224 and Bcal7 in populations of green toads (Bufo viridis complex) with various nuclear DNA content and ploidy

We studied variation of microsatellites BM224 and Bcal7 in three species of the Bufo viridis diploid-polyploid complex. We found that locus Bcal7 in all examined samples was monomorphic. Three alleles of microsatellite BM224 were found. Among tetraploid toads, the western species B. oblongus had only one allele variant, whereas the eastern species B. pewzowi had two other alleles. Similar distribution of alleles was observed in triploid specimens, collected in the area borders of tetraploid and diploid species. Among samples of diploid toad B. viridis, we found all three allele variants of microsatellite BM224. Their distribution was geographically determined. A comparison of allele distribution with genome size variation in diploid toads showed very similar patterns.     

Reproduction of Pratylenchus penetrans on 24 Common Weeds in Potato Fields in Qu��bec

Twenty-four weeds commonly found in commercial potato fields in Quebec were evaluated for their host suitability to the root-lesion nematode, Pratylenchus penetrans, under greenhouse conditions. Brown mustard (Brassica juncea) and rye (Secale cereale) were included as susceptible controls and forage pearl millet hyb. CFPM 101 (Pennisetum glaucum) as a poor host. Pratylenchus penetrans multiplied well on 22 of the 24 weed species tested (Pf/Pi ≥ rye or brown mustard). Cirsium arvense, Leucanthemum vulgare and Matricaria discoida were classified as very good hosts with a Pf/Pi ranging from 1.60 to 2.54, while Ambrosia artemisiifolia and Cyperus esculentus were classified as poor hosts with a Pf/Pi from 0.01 to 0.15. Amaranthus powellii, A. retrqflexus, Raphanus raphanistrum, Rorippa palustris, Cerastium fontanum, Spergula arvensis, Stellaria media, Chenopodium album, Vicia cracca, Elytrigia repens, Digitaria ischaemum, Echinochloa crusgalli, Panicum capillare, Setaria faberii, S. pumila, S. viridis, Polygonum convolvulus, P. scabrum and P. persicaria were intermediate hosts with Pf/Pi values ranging from 0.33 to 2.01. The plant species and the botanical family had a significant impact on nematode reproduction. The Brassicaceae family resulted in the greatest reproduction of P. penetrans, and the Cyperaceae resulted in the least. The plant life-cycle (annual vs. perennial) had no impact on nematode population.     

Variability of microsatellites BM224 and Bcal7 in populations of green toads (Bufo viridis complex) differing by nuclear DNA content and ploidy

The variability of microsatellites BM224 and Bcal7 was studied for the first time in three species of the diploid-polyploid complex of Bufo viridis (B. viridis, B. oblongus, and B. pewzowi). The locus Bcal7 was established to be monomorphic in all samples studied. In microsatellite BM224, three allele variants were found. Among tetraploid toads, the western Asiatic species B. oblongus was characterized by one allele only, the eastern B. pewzowi, by the two other alleles. A similar distribution was also revealed in triploid individuals on the borders of range between tetraploid and diploid species. Among the diploid species B. viridis samples, all three allele variants of microsatellite BM224 were observed. Their distribution in the area proved to be geographically determined. In diploid toads, a similarity was revealed between the distribution of microsatellite BM224 alleles and variability of the nuclear DNA content.     

Setaria viridis and Setaria italica, model genetic systems for the Panicoid grasses

Setaria italica and its wild ancestor Setaria viridis are diploid C(4) grasses with small genomes of ～515 Mb. Both species have attributes that make them attractive as model systems. Setaria italica is a grain crop widely grown in Northern China and India that is closely related to the major food and feed crops maize and sorghum. A large collection of S. italica accessions are available and thus opportunities exist for association mapping and allele mining for novel variants that will have direct application in agriculture. Setaria viridis is the weedy relative of S. italica with many attributes suitable for genetic analyses including a small stature, rapid life cycle, and prolific seed production. Setaria sp. are morphologically similar to most of the Panicoideae grasses, including major biofuel feedstocks, switchgrass (Panicum virgatum) and Miscanthus (Miscanthus giganteus). They are broadly distributed geographically and occupy diverse ecological niches. The cross-compatibility of S. italica and S. viridis also suggests that gene flow is likely between wild and domesticated accessions. In addition to serving as excellent models for C(4) photosynthesis, these grasses provide novel opportunities to study abiotic stress tolerance and as models for bioenergy feedstocks.     

Differences in muscle thermostability between diploid and tetraploid species of green toads (Bufo viridis complex) of Middle Asia

Significant differences were found between diploid (Bufo viridis) and tetraploid (B. danatensis) toad species in their skeletal muscle thermostability. The lower muscle thermostability in tetraploids may be associated with the adaptation of B. danatensis to colder conditions of arid mountain area in the Middle Asia.     

RNA and protein content in cells of diploid and tetraploid toads of the Bufo viridis group

Nucleic acids and total protein contents in hepatocytes and erythrocytes of diploid (Bufo viridis, 2n = 22) and tetraploid (B. danatensis, 2n = 44) green toads were measured cytophotometrically. The RNA (table 1) and protein (table 2) contents in the tetraploid cells are twice as much as that in diploid ones. According to these results tetraploidy in green toads may have a recent origin. The relation between structural and functional polyploidization in tetraploid amphibian species is discussed.     

Karyological and flow cytometric evidence of triploid specimens in Bufo viridis (Amphibia Anura)

Karyological and flow cytometric (FCM) analyses were performed on a group of 14 green toads of the Bufo viridis species from seven Eurasian populations. Both approaches gave concordant results concerning the DNA ploidy level. All the populations examined were represented exclusively by diploid or tetraploid specimens, except one, where triploids were found. Results evidenced an interpopulation variability in DNA content against the same ploidy level, as well as an unusually high number of triploids in a particular reproductive place. The origin of polyploidy and the presence and persistence of a high number of triploids in a particular population are discussed.     

Reference genome sequence of the model plant Setaria

We generated a high-quality reference genome sequence for foxtail millet (Setaria italica). The ～400-Mb assembly covers ～80% of the genome and >95% of the gene space. The assembly was anchored to a 992-locus genetic map and was annotated by comparison with >1.3 million expressed sequence tag reads. We produced more than 580 million RNA-Seq reads to facilitate expression analyses. We also sequenced Setaria viridis, the ancestral wild relative of S. italica, and identified regions of differential single-nucleotide polymorphism density, distribution of transposable elements, small RNA content, chromosomal rearrangement and segregation distortion. The genus Setaria includes natural and cultivated species that demonstrate a wide capacity for adaptation. The genetic basis of this adaptation was investigated by comparing five sequenced grass genomes. We also used the diploid Setaria genome to evaluate the ongoing genome assembly of a related polyploid, switchgrass (Panicum virgatum).     

Weedy adaptation in Setaria spp. V. Effects of gaseous environment on giant foxtail (Setaria faberii) (Poaceae) seed germination

The effects that naturally occurring gases (oxygen, nitrogen, carbon monoxide) may cause in dormant giant foxtail (Setaria faberii) seed germination under favorable temperature and moisture conditions were investigated. The germination responses to gas mixtures supported the hypothesis that S. faberii germination behavior is regulated by the amount of oxygen taken into hydrated seed over time. Setaria faberii seed germination was markedly affected by O(2) concentration (in N(2)) above and below that of air (20% O(2)): the largest increase in germination (from 37 to 60%) occurred between 20-25% O(2); between 0-10% O(2), germination increased from 0-30%; and surprisingly germination at 10 and 20% O(2) was similar. These observations reveal an asymmetrical response to incremental changes in O(2) above and below that typically found in agricultural soils. Carbon monoxide had opposite effects on S. faberii germination in air depending on concentration, stimulation, and inhibition: germination increased from 37 to 56% with the addition of 1% CO, but decreased from 37 to 14% with 75% added CO. An explanation may be that there are two separate effects of CO, each occurring in different physiological systems of dormant seeds at the same time. At high concentrations (75%) in air CO inhibited seed germination, probably by inhibiting mitochondrial respiration. But low CO concentrations (0.1 or 1%) in air stimulated seed germination. It was not apparent which physiological system(s) CO and O(2) affected. It seems unlikely that CO-stimulated germination arises from effects on the respiratory apparatus, but may be a consequence of CO interactions with an as yet unknown physiological factor in the seed. We provide a model of Setaria spp. dormancy consistent with its seed morphology, the gas-germination data, and the hypothesized second physiological factor that may be involved in CO stimulated germination.