Chromosome isolation by flow sorting in Aegilops umbellulata and Ae. comosa and their allotetraploid hybrids Ae. biuncialis and Ae. geniculata

This study evaluates the potential of flow cytometry for chromosome sorting in two wild diploid wheats Aegilops umbellulata and Ae. comosa and their natural allotetraploid hybrids Ae. biuncialis and Ae. geniculata. Flow karyotypes obtained after the analysis of DAPI-stained chromosomes were characterized and content of chromosome peaks was determined. Peaks of chromosome 1U could be discriminated in flow karyotypes of Ae. umbellulata and Ae. biuncialis and the chromosome could be sorted with purities exceeding 95%. The remaining chromosomes formed composite peaks and could be sorted in groups of two to four. Twenty four wheat SSR markers were tested for their position on chromosomes of Ae. umbellulata and Ae. comosa using PCR on DNA amplified from flow-sorted chromosomes and genomic DNA of wheat-Ae. geniculata addition lines, respectively. Six SSR markers were located on particular Aegilops chromosomes using sorted chromosomes, thus confirming the usefulness of this approach for physical mapping. The SSR markers are suitable for marker assisted selection of wheat-Aegilops introgression lines. The results obtained in this work provide new opportunities for dissecting genomes of wild relatives of wheat with the aim to assist in alien gene transfer and discovery of novel genes for wheat improvement.     

山羊草Aegilops kotschyi及其供体种Ae.longissima和Ae.umbellulata的醇溶蛋白研究

采用酸性聚丙烯酰胺凝胶电泳(APAGE)法对11份A担心Aegilops kotschyi及其S^1染色体组供体种Ae.longissima2份和U染色体组供体种Ae.umbellulata6份进行了醇溶蛋白位点的研究。结果表明：11份Ae.kotschyi共分离出32条带,31条具有多态性,占96．88％,每份材料可以分离出10-17条谱带,其中仅1条(3．12％)是共有带;11份Ae.kotschyi的遗传距离的变异范围在0-0.704之间,平均为0．409;11份Ae.kotschyi分离出的多数醇溶蛋白谱带均与其染色体组供体种Ae.longissi-ma及Ae.umbellulata相同,但仍有8条谱带未在两供体种中找到;11份Ae.kotschyi的醇溶蛋白多态性(96．88％)明显高于Ae.longissima(52．94％)与Ae.umbellulata(88．89％)11份Ae.kotschyi中有4份表现出了一定的特征带,分析知可能在γ区发生了较大的变异。     

Standard karyotypes ofAegilops uniaristata,Ae. mutica,Ae. comosa subspeciescomosa andheldreichii (Poaceae)

C-banding patterns and polymorphisms were analyzed in several accessions of the diploidAegilops speciesAe. uniaristata, Ae. mutica, andAe. comosa subsp.comosa and subsp.heldreichii, and standard karyotypes of these species were established. Variation in C-band size and location was observed between different accessions, but did not prevent chromosome identification. One accession ofAe. uniaristata was homozygous for whole-arm translocations involving chromosomes 1N and 5N. The homoeologous relationships of these chromosomes were established by comparison of chromosome morphologies and C-banding patterns to other diploidAegilops species with known chromosome homoeology. In addition, in situ hybridization analysis with a 5S rDNA probe was used to identify homoeologous groups 1 and 5 chromosomes. The present analysis permitted the assignment of allAe. mutica, comosa subsp.comosa, andAe. comosa subsp.heldreichii chromosomes, and three of the sevenAe. uniaristata chromosomes according to their homoeologous groups. The data presented will be useful analyzing genome differentiation in polyploidAegilops species.     

Metaphase I-bound arms frequency and genome analysis in wheat-Aegilops hybrids. 3. Similar relationships between the B genome of wheat and S or S l genomes of Ae. speltoides,Ae. longissima and Ae. sharonensis

The meiotic behaviour of Triticum aestivum × Aegilops speltoides, T. aestivum × Ae. sharonensis and T. aestivum × Ae. longissima tetraploid hybrids (genome constitution ABDS, ABDS ^l , and ABDS ^l , respectively) has been analysed by the C-banding technique. Of the six types of pairing normally occurring, at metaphase I three were recognized: A-D, AD-BS/AD-BS ^l and B-S/B-S ^l . The relative order observed in the low pairing hybrid, A-D> B-S ^l >AD-BS ^l , as well as that found in high-pairing Chinese Spring × Ae. speltoides hybrids, A-D>AD-BS>ß-S, revealed the existence of preferential pairing patterns among the different genomes that are in competition. In all of the hybrids analysed the mean number of bound arms per cell for the A-D type was significantly higher than the mean number of associations between the B and S/S ^l genomes. Usually the relative contribution of each type of pairing is maintained among hybrids with different Aegilops species. These results indicate that the genomes of Ae. speltoides, Ae. sharonensis and Ae. longissima show a similar affinity with the genomes of hexaploid wheat; therefore none of these species can be considered to be a distinct donor of the B genome of wheats.     

Report in Fruili-Venezia Giulia about Aedes cataphylla, Ae. communis, and Ae. pullatus, three rare mosquitoes in Italy

Data are provided on the ecology and morphology of Aedes cataphylla, Ae. communis e Ae. pullatus (Diptera, Culicidae), rare species for Italy, collected in the Friuli-Venezia Giulia Region (North-eastern Italy).     

粘、易、偏型非1BL／1RS小麦雄性不育系育性恢复性研究

以粘、易、偏型非1BL/1RS不育系ms(kots)-90-110、ms(var)-90-110为母本,一些优良小麦品种（系）为父本,广泛进行测交和育性恢复性分析,结果表明：（1）粘、易、偏型非1BL/1RS不育系不同于相同细胞质背景下1BL/1RS易位型不育系,突出地表现为：不育性稳定,恢复源广泛,高恢复度恢复系在普通小麦中占较大比例,且F1育性变异幅度小,变异系数低,并可将二者视为选择优良恢复系的辅助指标（2）粘、易、偏型非1BL/1RS不育系安全克服了同质1BL/1RS不育系产生单倍体的缺点,不育系和测交F1无单倍体产生;（3）粘、易、偏型非1BL/1RS不育系持有的易恢复性特点,为常规育种的最新成果直接应用于杂种小麦组配强优势组合创造了极有利条件。     

ph1b基因在普通小麦与Ae.crassa、Ae.crassassp杂种中的作用

通过对(中国春ph1b突变体×Ae. crassa)F_1、(中国春×Ae.crassa)F_1;(中国春ph1b突变体×Ae.crassassp)F_1、(中国春×Ae.crassassp)F_4花粉母细胞减数分裂中期Ⅰ染色体配对的研究。第一次证明了中国春ph1b突变体在诱导Ae.crassa、Ae.crassassp与普通小麦部分同源染色体配对方面有显著作用。可以利用ph1b基因通过诱导部分同源染色体配对交换的方法以染色体易位的方式把Ae.crassa和Ae.crassassp的有益基因导入普通小麦中。Ae.crassa和Ae.crassassp中不含有拟ph1基因。Ae.crassa和Ae.crassassp的D染色体组与普通小麦的D染色体组有明显区别。     

Characterization of low-molecular-weight-glutenin subunit genes from the D-genome of Triticum aestivum,Aegilops crassa,Ae. cylindrica and Ae. tauschii

Twenty low-molecular-weight-glutenin subunit (LMW-GS) gene sequences from the D-genome from Aegilops crassa (2n = 4x = 28), Ae. cylindrica (2n = 4x = 28), Ae. tauschii (2n = 2x = 14) and Triticum aestivum (2n = 6x = 42) were obtained using five sets of specific allele primer pairs. Only the sequences of the first primer pair were complete coding sequences (cds) of LMW-GS, and had 305, 304, 306 and 305 LMW-m amino acid residues in Ae. crassa, Ae. cylindrica, Ae. tauschii and T. aestivum, respectively. The repetitive domain and repeat motif numbers of all LMW glutenin subunits showed eight conserved cysteine residues that lead to the same functional activity in different genome. Based on DNA and predicted protein sequences, phylogenetic trees for all sets of sequences were drawn. At the DNA level, the species closest to T. aestivum for the second, third, fourth and fifth set of sequences were Ae. cylindrica, Ae. tauschii and Ae. crassa, respectively. At the protein level, the species closest to T. aestivum based on the first, second and fifth set of sequences were Ae. cylindrica, Ae. crassa and Ae. crassa, respectively. For other sets of sequences, bread wheat proved to be a distinct species. The LMW-GS gene sequences have been recorded in the GenBank with accession numbers JQ726549–JQ726568JQ726549JQ726550JQ726551JQ726552JQ726553JQ726554JQ726555JQ726556JQ726557JQ726558JQ726559JQ726560JQ726561JQ726562JQ726563JQ726564JQ726565JQ726566JQ726567JQ726568.     

Isozymes in Aegilops kotschyi and Ae. biuncialis x Secale cereale hybrids and Ae. kotschyi x S. cereale amphiploids in relation to their parents

Seven enzymatic systems in F1 Aegilops kotschyi and Ae. biuncialis x Secale cereale hybrids, Aegilops kotschyi x S. cereale amphiploids and their parental species (Ae. kotschyi, Ae. biuncialis and S. cereale) were analysed by starch and polyacrylamide gel electrophoresis. Five of them (phosphoglucose isomerase, glutamic oxalacetic transaminase, esterase, acid phosphatase, and diaphorase) were polymorphic and two (malic dehydrogenase and superoxide dismutase) were monomorphic. Several isophorms of phosphoclucose isomerase, esterase, acid phosphatase, and diaphorase were detected in some hybrids and amphiploids, but absent in the parents. The role of regulators, translocations and recombination is discussed in relation to the origin of these new isophorms. Some parental isozymes were absent both in hybrids and amphiploids, probably as a result of the suppression of structural genes in new combinations of the three genomes.     

Flow sorting of C-genome chromosomes from wild relatives of wheat Aegilops markgrafii,Ae. triuncialis and Ae. cylindrica,and their molecular organization

Background and Aims Aegilops markgrafii (CC) and its natural hybrids Ae. triuncialis (U^tU^tC^tC^t) and Ae. cylindrica (D^cD^cC^cC^c) represent a rich reservoir of useful genes for improvement of bread wheat (Triticum aestivum), but the limited information available on their genome structure and the shortage of molecular (cyto-) genetic tools hamper the utilization of the extant genetic diversity. This study provides the complete karyotypes in the three species obtained after fluorescent in situ hybridization (FISH) with repetitive DNA probes, and evaluates the potential of flow cytometric chromosome sorting.Methods The flow karyotypes obtained after the analysis of 4'',6-diamidino-2-phenylindole (DAPI)-stained chromosomes were characterized and the chromosome content of the peaks on the flow karyotypes was determined by FISH. Twenty-nine conserved orthologous set (COS) markers covering all seven wheat homoeologous chromosome groups were used for PCR with DNA amplified from flow-sorted chromosomes and genomic DNA.Key Results FISH with repetitive DNA probes revealed that chromosomes 4C, 5C, 7C^t, T6U^tS.6U^tL-5C^tL, 1C^c and 5D^c could be sorted with purities ranging from 66 to 91 %, while the remaining chromosomes could be sorted in groups of 2–5. This identified a partial wheat–C-genome homology for group 4 and 5 chromosomes. In addition, 1C chromosomes were homologous with group 1 of wheat; a small segment from group 2 indicated 1C–2C rearrangement. An extensively rearranged structure of chromosome 7C relative to wheat was also detected.Conclusions The possibility of purifying Aegilops chromosomes provides an attractive opportunity to investigate the structure and evolution of the Aegilops C genome and to develop molecular tools to facilitate the identification of alien chromatin and support alien introgression breeding in bread wheat.     

Multiple origins of U genome in two UM genome tetraploid Aegilops species, Ae. columnaris and Ae. triaristata, revealed based on the polymorphism of a genome-specific PCR fragment

To elucidate the evolutionary mode of the formation of species via polyploidization, we conducted phylogenetic analysis of the U genome of the UM genome tetraploid Aegilops species, Ae. columnaris and Ae. triaristata. Using the genome-specific PCR primer set U31, we investigated the variation of the U genome of 48 accessions each of Ae. columnaris and Ae. triaristata and 72 accessions of their diploid ancestor Ae. umbellulata. As a result, three alleles were distinguishable by amplified length and CAPS polymorphisms, namely, allele I = normal size with an MspI site, allele II = normal size without an MspI site, and allele III = shorter size caused by a 123bp deletion. All three alleles were detected both in diploid and tetraploid accessions. Sequence comparison indicated the inheritance of alleles I and III from the diploid to the tetraploids, suggesting multiple origins of the U genome of the tetraploids. Regarding allele II, however, the sequence comparison indicated that parallel mutations at the MspI site produced allele II several times. The phylogenetic tree based on the sequences of the U31 region demonstrated the presence of a third lineage of the U genome from Ae. umbellulata to Ae. columnaris. Consequently, we concluded that the U genome had at least three origins in Ae. columnaris, and at least two, probably more, in Ae. triaristata.     

Dissection of midgut and salivary glands from Ae. aegypti mosquitoes

The mosquito midgut and salivary glands are key entry and exit points for pathogens such as Plasmodium parasites and Dengue viruses. This video protocol demonstrates dissection techniques for removal of the midgut and salivary glands from Aedes aegypti mosquitoes.     

四倍体小麦—粗山羊草双二倍体抗病新种质的创制

通过四倍体小麦与粗山羊草杂交,利用幼胚拯救技术获得了ＰＳ５－Ｙ２８７双二倍体（ＡＡＢＢＤＤ）。该双二倍体ＰＭＣ ＭⅠ染色体构型基本稳定,对小麦白粉病表现免疫,对条锈、叶锈和秆锈病表现良好的田间抗性。并且该种质籽粒外观品质好,是一份有利用价值的小麦种质材料。     

来自粗山羊草抗条锈病基因的SSR标记

从粗山羊草[Aegilops tauschii (Coss.) Schmal] Y201中鉴定出1个显性抗小麦条锈病基因, 暂定名为YrY201。应用分离群体分组法(BSA) 筛选到Xgwm273b、Xgwm37和wmc14标记, 与该基因之间的遗传距离分别为11.9、5.8和10.9 cM。根据连锁标记所在小麦微卫星图谱的位置, YrY201被定位在7DL染色体上。分析基因所在染色体的位置及抗病性特征, 认为YrY201是一个新的抗小麦条锈病基因,并可用于分子标记辅助选择。     

Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter

Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. Even in winter, the lowest water temperature found in concrete tanks was >14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also indicate a concern about concrete tanks serving as foci for Ae. aegypti to expand their distribution in cooler regions.     

东方山羊草、尾状山羊草中染色体配对控制机制的存在和作用

直接杂交与幼胚培养方法结合获得了小麦与东方山羊草、尾状山羊草属间杂种。Ｆ１杂种细胞遗传学研究发现,东方山羊草的染色体组显著促进部分同源染色体配对,完全掩盖了小麦ｐｈ１ｂ基因的作用,尾状山羊草的染色体组一定程度抑制部分同源染色体配对,尤其强烈抑制小麦ｐｈ１ｂ基因的作用。表明东方山羊草的Ｓ染色体组上存在类似于小麦的ｐｈ１ｂ基因,尾状山羊草的Ｃ染色体组上存在类似于小麦的Ｐｈ１基因