Characterization of wheat/Aegilops ventricosa introgression and addition lines with respect to the Mv genome

Summary Stable wheat-Aegilops introgression lines with 42 chromosomes (H-93), derived by repeated selfing from a cross (Triticum turgidum x Aegilops ventricosa) x T. aestivum, have been characterized using the following DNA probes and isozyme markers: (1) single or low-copy DNA fragments from Ae. ventricosa; (2) known cDNA probes corresponding to 1-thionin, monomeric -amylase inhibitor, the CM3 subunit of tetrameric -amylase inhibitor, and sucrose synthase from wheat; (3) anonymous cDNA probes from wheat that have been mapped by Sharp et al. (1989); (4) isozyme markers corresponding to aconitase, shikimate dehydrogenase, adenylate kinase, and endopeptidase. Meiotic metaphases of appropriate hybrids involving selected H-93 lines have been investigated by the Giemsa C-banding technique. The substitution of whole chromosomes [(5A) 5M^v; (4D) 4M^v; (5D) 5M^v; (7D) 7M^v] and chromosomal segments (1M^v; 3M^v; 5M^v; 7M^v) from the M^v genome of Aegilops ventricosa has been demonstrated. The distribution of selected markers among putative wheat-Ae. ventricosa addition lines has also been investigated. The 7M^v addition has been characterized for the first time, while the identity of the previously reported 5M^v and 6M^v additions has been confirmed.     

Molecular and Structural Characterization of Barley Vernalization Genes

Vernalization, the requirement of a period of low temperature to induce transition from the vegetative to reproductive state, is an evolutionarily and economically important trait in the Triticeae. The genetic basis of vernalization in cultivated barley (Hordeum vulgare subsp. vulgare) can be defined using the two-locus VRN-H1/VRN-H2 model. We analyzed the allelic characteristics of HvBM5A, the candidate gene for VRN-H1, from ten cultivated barley accessions and one wild progenitor accession (subsp. spontaneum), representing the three barley growth habits – winter, facultative, and spring. We present multiple lines of evidence, including sequence, linkage map location, and expression, that support HvBM5A being VRN-H1. While the predicted polypeptides from different growth habits are identical, spring accessions contain a deletion in the first intron of HvBM5A that may be important for regulation. While spring HvBM5A alleles are typified by the intron-localized deletion, in some cases, the promoter may also determine the allele type. The presence/absence of the tightly linked ZCCT-H gene family members on chromosome 4H perfectly correlates with growth habit and we conclude that one of the three ZCCT-H genes is VRN-H2. The VRN-H2 locus is present in winter genotypes and deleted from the facultative and spring genotypes analyzed in this study, suggesting the facultative growth habit (cold tolerant, vernalization unresponsive) is a result of deletion of the VRN-H2 locus and presence of a winter HvBM5A allele. All reported barley vernalization QTLs can be explained by the two-locus VRN-H1/VRN-H2 model based on the presence/absence of VRN-H2 and a winter vs. spring HvBM5A allele. Electronic Supplementary Material Electronic Supplementary material is available for this article at and accessible for authorised users.     

Meiotic behaviour of Un,D and R genomes in the amphiploid Aegilops ventricosa -Secale cereale and the parental species

Summary Meiotic pairing frequencies of the Un and D genomes of Ae. ventricosa and the R of S. cereale could be easily established at metaphase I in Aegilops ventricosa — Secale cereale amphiploid plants as well as in its parental species by using the C-banding technique procedure. The results show a high diminution of chromosome pairing for all genomes in the amphiploid with respect to its parental species probably due to C-heterochromatin content and/or genotypic or cryptic interactions between the three genomes.     

Association of an isozyme locus and strawbreaker foot rot resistance derived from Aegilops ventricosa in wheat

Summary Thirty lines from a cross between VPM/ Moisson 421 and Selection 101 were used in the study to determine whether strawbreaker foot rot resistance derived from Aegilops ventricosa was associated with an allele for endopeptidase. The progeny examined for foot rot lesions represented F₂ derived F₅ lines and enzyme assays were done on F₆ seedlings. The results indicate that the wheat and VPM/Moisson 421 endopeptidase alleles are distinctly different. The endopeptidase allele frequencies of 30 lines were compared with strawbreaker foot rot resistance as measured by the lesion severity index. The results demonstrate a close association between the gene for strawbreaker foot rot resistance and the endopeptidase allele derived from Ae. ventricosa.     

Biochemical markers associated with two Mv chromosomes from Aegilops ventricosa in wheat-Aegilops addition lines

Summary The distribution of three biochemical markers, U-1, CM-4 and Aph_v-a, -b, among wheat-Aegilops addition lines carrying M^v chromosomes from Aegilops ventricosa (genomes D^vM^v) has been investigated. Addition lines which had been previously grouped together on the basis of common non-biochemical characters carried marker U-1, a protein component from the 2M urea extract. The added chromosome, in the appropriate genetic background, seems to confer a high level of resistance to the eyespot disease, caused by the fungus Cercosporella herpotrichoides. The other two markers were concomitantly associated with another similarly formed group of addition lines. Both CM-4, a protein component from the chloroform:methanol extract, and Aph_v-a, -b, alkaline phosphate isozymes, have been previously shown to be associated with homoeologous chromosome group 4, which suggests that the added chromosome in the second group of addition lines is 4M^v.     

小伞山羊草高分子量麦谷蛋白亚基及其基因的鉴定

运用SDS-PAGE和分子克隆技术,对小伞山羊草(Aegilops umbellulata,UU, 2n = 2x = 14)的高分子量麦谷蛋白亚基(1Ux, 1Uy)及其编码基因进行了鉴定.SDS-PAGE分析表明小伞山羊草不同基因型中的1Ux的电泳迁移率接近或慢于普通小麦1Dx2.2亚基的电泳迁移率,1Uy亚基的电泳迁移率一般接近或慢于普通小麦的1Dy类亚基.采用PCR扩增技术获得了1Ux和1Uy亚基编码基因的全长编码区,并对一个1Uy基因的全长编码区进行了全序列测定.对推导的氨基酸序列进行比较发现1Ux和1Uy亚基具有与来自于其他物种的高分子量麦谷蛋白亚基一致的一级结构,聚类分析显示1Ux和1Uy亚基与D基因组编码的高分子量麦谷蛋白亚基在起源和进化上具有较高的相似性.     

小伞山羊草高分子量麦谷蛋白亚基及其基因的鉴定

运用SDS_PAGE和分子克隆技术 ,对小伞山羊草 (Aegilopsumbellulata ,UU ,2n =2x =14)的高分子量麦谷蛋白亚基 (1Ux ,1Uy)及其编码基因进行了鉴定。SDS_PAGE分析表明小伞山羊草不同基因型中的 1Ux的电泳迁移率接近或慢于普通小麦 1Dx2 .2亚基的电泳迁移率 ,1Uy亚基的电泳迁移率一般接近或慢于普通小麦的 1Dy类亚基。采用PCR扩增技术获得了 1Ux和 1Uy亚基编码基因的全长编码区 ,并对一个 1Uy基因的全长编码区进行了全序列测定。对推导的氨基酸序列进行比较发现 1Ux和 1Uy亚基具有与来自于其他物种的高分子量麦谷蛋白亚基一致的一级结构 ,聚类分析显示 1Ux和 1Uy亚基与D基因组编码的高分子量麦谷蛋白亚基在起源和进化上具有较高的相似性。     

Biochemical and cytological characterization of wheat/Aegilops ventricosa addition and transfer lines carrying chromosome 4MV

Summary The gene encoding a variant of alcohol dehydrogenase, Adh-, has been found to be associated with the chromosome of the M^v genome which is present in type 9 wheat/Aegilops ventricosa addition line, to which the genes for protein CM-4 and for a phosphatase variant, Aph-v, had been previously assigned. Transfer line H-93-33, which has 42 chromosomes and has been derived from the cross (Triticum turgidum x Ae. ventricosa) x T. aestivum, carries genes encoding all three biochemical markers. Linkage between these genes has been demonstrated by analysis of individual kernels of the F2 (H-93-33 x T. aestivum cv. Almatense H-10-15). A study of the hybrids of line H-93-33 with T. aestivum H-10-15 and with the 4DS ditelosomic line has confirmed that, as suspected, the linkage group corresponds to chromosome 4M^v from Ae. ventricosa. Additionally, it has been found that the previously reported resistance of line H-93-33 to powdery mildew (Erysiphe graminis) is also linked to the biochemical markers; this indicates that either the gene responsible for it is different from that in lines H-93-8 and H-93-35, or that a translocation between two different M^v chromosomes has occurred in line H-93-33.     

Genetic transfer of resistance to powdery mildew and of an associated biochemical marker from Aegilops ventricosa to hexaploid wheat

Summary Resistance to powdery mildew, caused by the fungus Erysiphe graminis f.sp. tritici, has been transferred from Aegilops ventricosa (genomes D^vM^v) to hexaploid wheat (Triticum aestivum, ABD). In two transfer lines, H-93-8 and H-93-35, the resistance gene was linked to a gene encoding protein U-1, whereas one line, H-93-33, was resistant but lacked the molecular marker, and another line, H-93-1, was susceptible but carried the gene for U-1, indicating that the original M^v chromosome from Ae. ventricosa, carrying the two genes, had undergone recombination with a wheat chromosome in the last two lines.     

Molecular Evolution of hisB Genes

The sixth and eighth steps of histidine biosynthesis are catalyzed by an imidazole glycerol-phosphate (IGP) dehydratase (EC 4.2.1.19) and by a histidinol-phosphate (HOL-P) phosphatase (EC 3.1.3.15), respectively. In the enterobacteria, in Campylobacter jejuni and in Xylella/Xanthomonas the two activities are associated with a single bifunctional polypeptide encoded by hisB. On the other hand, in Archaea, Eucarya, and most Bacteria the two activities are encoded by two separate genes. In this work we report a comparative analysis of the amino acid sequence of all the available HisB proteins, which allowed us to depict a likely evolutionary pathway leading to the present-day bifunctional hisB gene. According to the model that we propose, the bifunctional hisB gene is the result of a fusion event between two independent cistrons joined by domain-shuffling. The fusion event occurred recently in evolution, very likely in the proteobacterial lineage after the separation of the - and the -subdivisions. Data obtained in this work established that a paralogous duplication event of an ancestral DDDD phosphatase encoding gene originated both the HOL-P phosphatase moiety of the E. coli hisB gene and the gmhB gene coding for a DDDD phosphatase, which is involved in the biosynthesis of a precursor of the inner core of the outer membrane lipopolysaccharides (LPS).     

Origin and differentiation of Aegilops triuncialis L. as determined by esterase isozyme analysis

Summary Banding patterns of esterase isozymes in Aegilops triuncialis (2n = 28, genome formula C^uC^uCC) and its putative parental species, Ae. umbellulata (2n = 14, C^uC^u) and Ae. caudata (2n = 14, CC), were studied by the gel isoelectric focusing method using pH 6–8 carrier ampholite. Zymogram phenotypes of both parents were quite uniform. Seven zymogram phenotypes (designated as phenotypes 1 to 7) were found among the 260 strains of Ae. triuncialis examined. Of these phenotypes, phenotype 1 was identical to the zymogram phenotype produced by the ancestral species, Ae. umbellulata, and bands considered to have been derived from Ae. caudata were absent in this phenotype. Phenotype 3 had all bands of both parents. The other phenotypes differed greatly from phenotype 3. Therefore, phenotype 3 was considered to be most primitive of the 7 types, and the Ae. triuncialis strains which showed phenotype 3 to be the most primitive of the strains examined. If Ae. triuncialis originated as a hybrid between Ae. umbellulata and Ae. caudata, the zymogram phenotype must have been phenotype 3, in which the isozymes of both parental species are present. Whether the phenotypes other than type 3 were due to introgressive hybridization could not be verified, but they were considered in this article to be a consequence of a rearrangement of chromosomes.Contribution from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University No. 432     

Linkage mapping of prolamin and isozyme genes on the 1Sl chromosome of Aegilops longissima

The storage proteins and isozymes of two accessions of Aegilops longissima, and the F₂ progeny from the cross between them, were analyzed. Six loci were identified on the 1S^l chromosome: Glu-S ^l 1 (coding for HMW subunits of glutenin), Gpi-S ^l 1 (coding for a Gpi isozyme), Glu-S ^l 3 (coding for LMW subunits of glutenin), Gli-S ^l 1 (coding for gliadins) and two, so far, not described new loci Gli-S ^l 4 and Gli-S ^l 5. The Gli-S ^l 4 locus codes for a -gliadin and the Gli-S ^l 5 codes for a gliadin with mobility in the -region. The genetical distances found between the six loci allowed the establishment of the following gene order on the 1S^l chromosome: Glu-S ^l 1 —centromere —Gpi-S ^l 1 — Gli-S ^l 4 — Gli-S ^l 3 — Gli-S ^l 1 -Gli-S ^l 5.     

Control of lectins in Triticum aestivum and Aegilops umbellulata by homoeologous group 1 chromosomes

Summary Each of the three genomes in hexaploid wheat controls the expression of a specific lectin in the embryo. The chromosomes which control their synthesis were determined using nullisomic-tetrasomic and inter-varietal chromosome substitution lines of Chinese Spring. All three wheat lectins were shown to be controlled by the homoeologous group 1 chromosomes. Using ditelosomic lines of Chinese Spring the lectin genes could be localized on the long arms of chromosomes 1A and 1D. Inter-specific addition and substitution lines of Aegilops umbellulata chromosomes to Chinese Spring indicated that chromosome 1U, which is homoeologous to the group 1 chromosomes of wheat, controls lectin synthesis.     

Molecular genetics of puroindolines and related genes: allelic diversity in wheat and other grasses

The hardness or texture of cereal grains is a primary determinant of their technological and processing quality. Among members of the Triticeae, most notably wheat, much of the variation in texture is controlled by a single locus comprised of the Puroindoline a, Puroindoline b and Grain Softness Protein-1 (Gsp-1) genes. Puroindolines confer the three major texture classes of soft and hard common wheat and the very hard durum wheat. The protein products of these genes interact with lipids and are associated with the surface of isolated starch (as a protein fraction known as ‘friabilin’). During the past ten years a great diversity of alleles of both Puroindoline genes have been discovered and significant advances made in understanding the relationship between the gene presence/absence, sequence polymorphism and texture of cereal grains. Efforts have also focussed on Puroindoline and Gsp-1 genes in diploid progenitors, other Triticeae grasses and synthetic wheats in order to understand the evolution of this gene family and find potentially useful variants. The puroindoline homologues in other cereals such as rye and barley are also receiving attention. This work summarises new developments in molecular genetics of puroindolines in wheat and related Triticeae grasses, and the related genes in other cereals.     

Determination of the transmission frequency of chromosome 4S l of Aegilops sharonensis in a range of wheat genetic backgrounds

Summary The transmission of chromosome 4S ^l from Aegilops sharonensis was observed in a range of wheat genetic backgrounds. Chromosome 4S ^l was transmitted at a very high frequency (at least 97.8%) in all crosses. The genetic background appears to only have a small effect on transmission. The frequency of transmission of chromosome 4S ^l was the same in each genetic background through both the male and female gametes.     

Eyespot resistance gene Pch-1 in H-93 wheat lines. Evidence of linkage to markers of chromosome group 7 and resolution from the endopeptidase locus Ep-D1b

Summary Gene Pch1, which confers resistance to eyespot disease (Pseudocercosporella herpotrichoides Fron), has been located on chromosome 7D in the H-93 wheat-Aegilops ventricosa transfer lines using isozyme markers and DNA probes corresponding to group 7 chromosomes. Previous experiments had failed to ascertain this location. The lack of segregation of the resistance trait in progeny from reciprocal crosses between lines H-93-70 and VPM1 indicates that their respective resistance factors are allelic. Line H-93-51 carries the endopeptidase allele Ep-D1b but is susceptible to eyespot, which indicates that resistance to eyespot is not a product of the Ep-D locus, as had been proposed in a previous hypohesis.     

Genomic analysis in the genus Aegilops.

Summary Hybrids between different Aegilops species and Secale cereale were studied at metaphase I by means of a C-banding technique. On the basis of differences in the C-banding patterns of some of the chromosomes of these hybrids it was possible to carry out an accurate analysis of several types of Aegilops-Aegilops and Aegilops-Secale chromosome associations and, consequently, to establish intraspecific and intergeneric genome relationships. Genomes present in the majority of polyploid Aegilops species are shown to maintain similar patterns of evolutionary affinity to those reported for their proposed diploid parents although in some species there are differences indicating either that differentiations occurred during the evolution of the polyploid species or, on the contrary, that the diploid donors proposed are not the correct ones. On the other hand, differences in the relationships not only between the R genome and different Aegilops genomes but also among different homoeologous groups have been found.     

产甘油假丝酵母与酿酒酵母胞浆3-磷酸甘油脱氢酶基因的功能比较

胞浆3-磷酸甘油脱氢酶(GPD)是酿酒酵母细胞甘油合成过程中的关键限速酶．尽管高产甘油菌株产甘油假丝酵母基因组中编码该酶的基因CgGPD已经被克隆出来,但是具体的功能,特别是与酿酒酵母GPD1和GPD2基因的功能比较值得进一步研究．以酿酒酵母渗透压敏感型的gpd1/gpd2和gpd1突变株为宿主,分别导入CgGPD、GPD1和GPD2基因,比较分析了CgGPD、GPD1和GPD2基因在高渗透压胁迫条件下和厌氧环境中的表达调控,及其对细胞甘油合成能力的影响．研究发现,GPD1基因受到渗透压诱导表达,GPD2基因在细胞厌氧条件下起着氧化还原平衡调节作用,而CgGPD基因不仅能够在渗透压胁迫条件下通过过量快速合成甘油调节渗透压平衡,而且能够在厌氧培养环境中互补GPD2基因的缺失,使gpd1/gpd2缺失突变株能够正常生长,同时提高了突变株的甘油合成能力．结果表明,CgGPD基因在gpd1/gpd2缺失突变株中既具有GPD1基因的功能,又能发挥GPD2基因的功能．