谷子和狗尾草核型分析

作者研究了我国谷子(Setaria italica Beauv.)和狗尾草的核型与Giemsa带,两者核型基本相同,均为2n=18=14m+2sm+2st(SAT)。带型亦相近,另外在谷子和狗尾草中都发现有四倍体。     

青藏高原野生大麦和瓦兰大麦的核型及带型研究

本文报道了我国特有大麦——青藏高原野生普通大麦和瓦兰大麦的核型及N带带型。其核型均为2n=2x=14=12m(2SAT)+2sm(2SAT),均属2A类型。野生普通大麦的N带带型为2n=2x=14=2 C/CI+2 C/CI+2 C/CI+2 CI/CI+2 C/CI+2 CN/CI+2 CI/CI,瓦兰大麦的N带带型为2n=2x=14=2 C/CI+2 C/CI+2 C/CI+2 CI/CI+2 C/CI+2 CIN/CI+2 CI/CI,野生普通大麦、瓦兰大麦与栽培大麦在核型上无明显差异,野生普通大麦与瓦兰大麦带型差异明显,且野生普通大麦与栽培大麦间的带型差异大于瓦兰大麦与栽培大麦间的带型差异。分析表明,在进化关系上,野生普通大麦要原始一些,瓦兰大麦要进化一些。文章还对大麦核型及显带等方面的研究进行了讨论。     

不同居群白木香的染色体研究

采用常规压片法和改良BSG法对3个居群白木香的染色体核型及Giemsa C-带带型进行研究。结果表明:3个居群白木香的核型均属2B类型,其中广西居群白木香的核型公式为2n=16=4m+8sm+4st;其他两个居群白木香的核型公式为2n=16=6m+6sm+4st,居群间核型变异不明显。白木香的C带带型为CIT型,具有着丝粒带、中间带、端带和全带。3个居群白木香C带的分布、数目和类型不完全一样,出现了带型的多态性。     

二种薏苡的核型和C-带带型的研究

川谷和薏苡的核型极为相似,2n=20=18m(2SAT)+2sm,属较为对称的核型。它们的C-带带型也极为相似,多数为端带,少数为弱近端带,没有着丝点带,薏苡的带比川谷的带要丰富些。川谷的C_-带带型可表示为:2n=20=6T_++2T_+~++2T_+S+10,薏苡的C_-带带型为:2n=20=6T_++6T~++6T_+~++2S。     

秦巴山区重楼属的核型研究

本文报道了陕西秦巴山区几种重楼属植物的核型研究结果。在秦岭(太白山)地区,北楼(Paris verticillata)具有一种核型,其核型公式为 2n=4 x=20=10m+2sm+4st+4t;狭叶重楼(P.polyphylla var.stenophylla)在一个居群内不同的个体间具有两种不同的核型,核型公式分别为2n=2x=10=5m+1sm+4t和2n=2x=10+2B=6m+4t+2B。在秦岭和巴山两地,宽叶重楼(P.polyphylla var.latifolia)和球药隔重楼(P.fargesii)分别具有两种不同的核型,前者的核型公式为2n=2x=10+3B=6m+3t+3B和2n=2x=10=5m+1sm+4t,后者的核型公式为2n=2x=10+2B=4m+2sm+4t+2B和2n=2x=10+2B=6m+4t+2B。这些材料均属2A核型,在核型结构及B染色体的有无和数目上与前人报道的结果不完全相同。     

东北地区野豌豆属VICIA L.物种生物学研究——Ⅵ.柳叶野豌豆复合种及其近缘种核型分析和细胞地理学研究

本文报道了国产北野豌豆Vicia ramuliflra(Maxim.)Ohwi和日本产V.fauviei Franch.和V.nipponica Matsum.的核型。北野豌豆古莲居群2n=12=2m(2SAT)+8sm+2st, 千山居群2n=12=6m+6sm。V.fauriei 2n=12=2m+8sm+2st, V.nipponica 2n=12=6m(4SAT)+4sm+2st, 核型分析表明核型主要由'm'、'sm'和'st'三种染色体组成, 核型对称性高(2A或3A)。染色体倍性分布格局, 形态特征和现代分布式样揭示黄山-西天目山-庐山-带山地可能是柳叶野豌豆复合种及其近缘种的起源中心和多样化中心, 四倍体的发生可能与第四纪山地冰川有关。     

伞形花科5种主要蔬菜作物的核型分析

采用卡宝染色压片法对伞形花科5种主要蔬菜作物进行了核型分析和比较.结果表明:芹菜的核型公式为K(2n)=2x=22=6m+2sm+8st+6t,染色体核型为"3B"型;芫荽的核型公式为K(2n)=2x=22=2m+2sm+18st,染色体核型为"3A"型;茴香的核型公式为K(2n)=2x=22=14m+6sm+2st,染色体核型为"2B"型;水芹的核型公式为K(2n)=2x=22=6m+6sm+10st,染色体核型为"3A"型;胡萝卜的核型公式为K(2n)=2x=18=6m+10sm+2st,染色体核型为"2A"型.并对他们的亲缘关系、遗传多样性进行了探讨.     

青藏高原5种石竹科垫状植物的核型研究

垫状植物是高山冰缘带植物区系的重要组成成分,是植物适应高寒环境趋同进化的特殊生活型。该研究以采自西藏和云南高山冰缘带的5种石竹科垫状植物种子为材料,采用滤纸萌发法、常规压片法镜检观察分析其核型,为青藏高原垫状植物积累核型资料,并为探讨极端环境下特殊生活型植物的核型进化机制提供依据。结果表明:5种植物均为二倍体,染色体核型分别为:密生福禄草(Arenaria densissima),2n=2x=20m+2sm,2A;山生福禄草(A.oreophila),2n=2x=22m,1A;团状福禄草(A.polytrichoides),2n=2x=20m+2sm,2A;大花福禄草(A.smithiana),2n=2x=20m+2sm,1A;囊种草(Thylacospermum caespitosum),2n=2x=18m+4sm,2A。囊种草与福禄草亚属植物的染色体数目一致,为二者在分子系统发育框架下形成的独立分支提供核型证据。并讨论了5种垫状植物古多倍体物种形成的核型进化与中新世青藏高原及周边地区地质抬升的关联。     

黄精属5种植物的核型研究

本文报道了安徽省黄精属Polygonatum Mill．5种植物的染色体数目和核型。玉竹P. odoratum (Mill.)Druce黄山材料2n=16=10m(3sc)+6sm,滁县琅琊山材料2n=18=10m(1sc) +2sm+6st(2sc),二者均属2B核型． 长梗黄精P．filipes Mirr. 黄山材料2n=22=8m+8sm(2sc)+6st,属3B核型,安徽繁昌材料2n=14=10m+4sm和2n=16=8m +4sm+4st,二者均属2B核型。多花黄精(P.cyrtonema Hua)安徽黄山材料2n=20=8m+6sm+6st和2n=22=6m+8sm +4st+4t,二者均属3B核型,安徽滁县琅琊山材料2n=18=8m(2sc)+6sm+4st,属2B核型。长苞黄精(P．desoulayi kom．) 2n=22=10m(2sc)+6sm(1sc)+6st,属3B核型;轮叶黄精(P．verticillatum(L．)All．)2n=18=2m+2sm+10st+2t+2T和2n=24=6m+4sm+12st+2T,二者均属3B核型。其中玉竹2n=16,长梗黄精2n=14和2n=22,长苞黄精2n=22,轮叶黄精2n=18的染色体数目和核型均为首次报道。     

珍珠菜属三种植物的核型研究

对国产三种珍珠菜属 (Lysimachia)植物进行了核型研究 ,其中点腺过路黄 (LysimachiahemsleyanaMaxim .)染色体核型 2n =2 2 =2m +4sm +8st+8t,聚花过路黄 (L .congestifloraHesmsl.)核型 2n =2 4=2m +2sm +1 0st+1 0t及山萝过路黄 (L .melampyroidesR .Knuth)染色体数目 2n =2 2 ,核型 2n =2 2 =4m +6sm +4st+8t,为首次报道。本文还分析了黄连花亚属 (subgen.Lysimachia) 2组 8种植物的核型 ,结果表明黄连花组(sect.Lysimachia)核型类型 1A ,过路黄组 (sect.Nummularia)核型类型 3A或 3B。     

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.     

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.     

An isoleucine-leucine substitution in chloroplastic acetyl-CoA carboxylase from green foxtail (<Emphasis Type="Italic">Setaria viridis</Emphasis> L. Beauv.) is responsible for resistance to the cyclohexanedione herbicide sethoxydim

The cDNAs encoding chloroplastic acetyl-CoA carboxylase (ACCase, EC 6.4.1.2) from three lines of Setaria viridis (L. Beauv.) resistant or sensitive to sethoxydim, and from one sethoxydim-sensitive line of Setaria italica (L. Beauv.) were cloned and sequenced. Sequence comparison revealed that a single isoleucine-leucine substitution discriminated ACCases from sensitive and resistant lines. Using near-isogenic lines of S. italica derived from interspecific hybridisation, we demonstrated that the transfer of the S. viridis mutant ACCase allele into a sethoxydim-sensitive S. italica line conferred resistance to this herbicide. We confirmed this result using allele-specific polymerase chain reaction and showed that a single copy of the mutant allele is sufficient to confer resistance to sethoxydim. We conclude that a mutant allele of chloroplastic ACCase encoding a leucine residue instead of an isoleucine residue at position 1780 is a major gene of resistance to sethoxydim.     

Population dynamics and diapause response of the springtail pest Sminthurus viridis (Collembola: Sminthuridae) in southeastern Australia

The springtail, Sminthurus viridis (L.) (Collembola: Sminthuridae), is an important agricultural pest across southern Australia. We investigated the seasonal abundance patterns and summer diapause response of S. viridis in southeastern Australia by using field and shadehouse (a greenhouse that offers seedlings shade) experiments. Seasonal activity patterns of S. viridis were largely consistent with previous studies, with the pest active from autumn to spring. In addition, the timing and pattern of the summer-diapausing egg stage was established, with multiple generations probably producing diapause eggs. A strong relationship between soil moisture and temperature with autumn emergence also was observed. These results suggest that S. viridis autumn pest pressure can be predicted and indicate that late-season spraying strategies currently used for a sympatric agricultural pest are unlikely to be as effective against S. viridis.     

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).     

Fitness costs linked to dinitroaniline resistance mutation in Setaria

A mutant Thr-239-Ileu at the α2-tubulin gene was found to confer resistance to dinitroanilines, a family of mitosis-disrupting herbicides. However, mutations affecting microtubule polymerization and cell division are expected to impact growth and reproduction, that is, the fitness of a resistant weed or the yield of a tolerant crop, although it has not been demonstrated yet. This study was designed to test this hypothesis for the growth and reproduction of near-isogenic resistant and susceptible materials that were created in F(2) and F(3) generations after a Setaria viridis x S. italica cross. Differential growth was noticeable at the very onset of seedling growth. The homozygous resistant plants, grown both in a greenhouse cabinet and in the field, were smaller and had lower 1000-grain weight and therefore a lower yield. This fitness penalty is certainly due to modified cell division kinetics. Although the presence of the mutant allele accounted for 20% yield losses, there were also measurable benefits of dinitroaniline resistance, and these benefits are discussed.     

Regeneration of somatic hybrids in relation to the nuclear and cytoplasmic genomes of wheat and Setaria italica.

Somatic hybridization via PEG (Polyethylene 6000)-mediated protoplast fusion was achieved between two different wheat culture lines (Triticum aestivum L., "Jinan"177, T1 and T2) and Setaria italica (L.) P. Beauv. The T1 recipient originated from non-regenerable long-term cell suspensions, while T2 was derived from embryogenic calli with a high regeneration capacity. Donor protoplasts were obtained from embryogenic calli of S. italica (S) (with low regeneration capacity) irradiated with different doses of ultraviolet light. Twenty-three putative hybrid cell lines were produced in fusion combinations with the donor protoplasts treated with UV light for 30 s (combination I) and 1 min (combination II), but only one (from combination II) differentiated into green plants. Three cell lines from combination I and five cell lines from combination II possessed the nuclear genomes of T1, T2, and S. italica as revealed by cytological, isozyme, RAPD, and 5S rDNA spacer sequence analyses. Genomic in situ hybridization (GISH) analysis showed that most hybrid cell lines had 22-36 wheat chromosomes, 0-2 S. italica chromosomes, and 1-6 wheat - S. italica recombinant chromosomes, whereas the regenerable cell line had 44-56 wheat chromosomes and 3-6 recombinant chromosomes, but no intact S. italica chromosomes. RFLP analysis of organellar DNA revealed that mitochondrial and chloroplast DNA of both parents coexisted in all hybrid cell lines and recombined in most hybrid cell lines. These results indicate that the regeneration of hybrid plants involves not only the integration of S. italica nuclear and organellar DNA, but also the genome complementation of T1 and T2.     

The isolation of Naegleria italica from Peru indicates that this potentially pathogenic species occurs worldwide

The amoeboflagellate genus Naegleria includes a few species that are virulent in experimental animals. One of these species, Naegleria italica, has been isolated from the environment only in Italy and Australia. I report here the isolation of a strain of N. italica from a water sample collected in Peru. This broadens the occurrence of this species to encompass three different continents. This new N. italica isolate from Peru has the same ITS1, 5.8S rDNA and ITS2 sequence as that of the type strain from Italy and the isolate from Australia. From the same water body in Peru a Naegleria strain was isolated that differs from N. italica by only one additional base pair in the ITS2 sequence. The maximum growth temperature tolerated by this particular isolate is 40 degrees C, which is different from that of N. italica, which is 42 degrees C.     

利用野生青狗尾草的细胞质培育谷子质核互作雄性不育材料

利用野生青狗尾草N10为母本,谷子农家品种大青秸为父本,进行种间杂交,获得了3株杂种。杂种在农艺性状上表现为谷子和青狗尾草的种间类型,花器表现了雄性败育,但雌蕊发育正常,能接受外来花粉结实。细胞形态学观察表明,其雄性败育表现为单核小孢子典败。该谷子雄性不育材料的获得,为利用野生青狗尾草的细胞质培育谷子质核互作雄性不育系,进而为实现谷子三系配套杂种优势利用奠定了基础。     

Genetic structure of landraces in foxtail millet (Setaria italica (L.) P. Beauv.) revealed with transposon display and interpretation to crop evolution of foxtail millet

Although the origin and domestication process of foxtail millet (Setaria italica subsp. italica (L.) P. Beauv.) has been studied by several groups, the issue is still ambiguous. It is essential to resolve this issue by studying a large number of accessions with sufficient markers covering the entire genome. Genetic structures were analyzed by transposon display (TD) using 425 accessions of foxtail millet and 12 of the wild ancestor green foxtail (Setaria italica subsp. viridis (L.) P. Beauv.). We used three recently active transposons (TSI-1, TSI-7, and TSI-10) as genome-wide markers and succeeded in demonstrating geographical structures of the foxtail millet. A neighbor-joining dendrogram based on TD grouped the foxtail millet accessions into eight major clusters, each of which consisted of accessions collected from adjacent geographical areas. Eleven out of 12 green foxtail accessions were grouped separately from the clusters of foxtail millet. These results indicated strong regional differentiations and a long history of cultivation in each region. Furthermore, we discuss the relationship between foxtail millet and green foxtail and suggest a monophyletic origin of foxtail millet domestication.