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.     

Production and characterization of amphiploids of Aegilops kotschyi and Ae. biuncialis with Secale cereale, and of backcross hybrids of Ae. biuncialis x S. cereale amphiploids with 2x and 4x S. cereale

Amphiploids (2n = 6x = 42) of Ae. kotschyi and Ae. biuncialis with self-compatible S. cereale were produced from F1 sterile hybrids (2n = 3x = 21) through colchicine treatment and callus tissue regeneration. The amphiploids resembled the F1 plants in overall morphology, but were larger in all respects and self-fertile. The spikelets consisted mostly of 3 well-developed florets. Selfed seeds were obtained from some colchicine-doubled sectors and callus regenerates. Most of the produced seeds were well developed. Backcrosses between amphiploids and rye (2x and 4x) resulted in obtaining (Ae. biuncialis x S. cereale amphiploid) x S. cereale hybrids via embryo culture. The BC1 plants (2n = 4x = 28 and 2n = 5x = 35, respectively) were phenotypically intermediate between the parents and vigorous in vegetative growth. Some seeds were obtained only from the 35-chromosome BC1 hybrids.     

Chromosome pairing in the allotetraploid Aegilops biuncialis and a triploid intergeneric hybrid.

Chromosome pairing behaviour of the natural allotetraploid Aegilops biuncialis (genome UUMM) and a triploid hybrid Ae. biuncialis x Secale cereale (genome UMR) was analyzed by electron microscopy in surface-spread prophase I nuclei. Synaptonemal-complex analysis at zygotene and pachytene revealed that synapsis in the allotetraploid was mostly between homologous chromosomes, although a few quadrivalents were also formed. Only homologous bivalents were observed at metaphase I. In contrast, homoeologous and heterologous chromosome associations were common at prophase I and metaphase I of the triploid hybrid. It is concluded that the mechanism controlling bivalent formation in Ae. biuncialis acts mainly at zygotene by restricting pairing to homologous chromosomes, but also acts at pachytene by preventing chiasma formation in the homoeologous associations. In the hybrid the mechanism fails at both stages. Key words : Aegilops biuncialis, allotetraploid, intergeneric hybrid, pairing control, synaptonemal complex.     

Hybrids and amphiploids of Aegilops ovata L. with Secale cereale L.: production,morphology and fertility

Hybrids (2n = 3x = 21) between Aegilops ovata and Secale cereale were produced via embryo rescue. Most hybrid morphological traits were intremediate between parents, the plants grew vigorously but were completely sterile. The average frequency of chromosome associations at metaphase I was 19.57-20.19 univalents and 0.40-0.86 rod bivalents. The fertility of the hybrids was restored by doubling their chromosome numbers by colchicine treatment and in vitro propagation. Selfed seeds were obtained from colchicine-doubled sectors and some callus regenerates. The seeds were mostly well formed and developed vigorous plants without embryo culture. Colchicine- and callus-derived amphiploids (2n = 6x = 42) resembled the F(1) plants in overall morphology, but showed a lower tillering ability, broader leaves, thicker culms and larger spikes.     

Molecular cytogenetic characterization of Aegilops biuncialis and its use for the identification of 5 derived wheat-Aegilops biuncialis disomic addition lines.

The aim of the experiments was to produce and identify different Triticum aestivum-Aegilops biuncialis disomic addition lines. To facilitate the exact identification of the Ae. biuncialis chromosomes in these Triticum aestivum-Ae. biuncialis disomic additions, it was necessary to analyze the fluorescence in situ hybridization (FISH) pattern of Ae. biuncialis (2n = 4x = 28, U(b)U(b)M(b)M(b)), comparing it with the diploid progenitors (Aegilops umbellulata, 2n = 2x = 14, UU and Aegilops comosa, 2n = 2x = 14, MM). To identify the Ae. biuncialis chromosomes, FISH was carried out using 2 DNA clones (pSc119.2 and pAs1) on Ae. biuncialis and its 2 diploid progenitor species. Differences in the hybridization patterns of all chromosomes were observed among the 4 Ae. umbellulata accessions, the 4 Ae. comosa accessions, and the 3 Ae. biuncialis accessions analyzed. The hybridization pattern of the M genome was more variable than that of the U genome. Five different wheat-Ae. biuncialis addition lines were produced from the wheat-Ae. biuncialis amphiploids produced earlier in Martonvásár. The 2M, 3M, 7M, 3U, and 5U chromosome pairs were identified with FISH using 3 repetitive DNA clones (pSc119.2, pAs1, and pTa71) in the disomic chromosome additions produced. Genomic in situ hybridization (GISH) was used to differentiate the Ae. biuncialis chromosomes from wheat, but no chromosome rearrangements between wheat and Ae. biuncialis were detected in the addition lines.     

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.     

普通小麦1BL—1RS K,V型雄性不育体系育性恢复的研究

对１ＢＬ－１ＲＳ Ｋ,Ｖ型雄性不育系及其保持素与中国春及其第一部分同源群染色体全部６个缺－四体杂种Ｆ１的育性恢复进行了研究。结果表明：Ｋ型杂种的育笥恢复主要受１ＢＳ上Ｒｆｖ１基因的控制;而Ｖ杂种则受Ｒｆｖ１的１Ｄ染色上育性恢复基因的共同控制;在保持１Ｄ正常剂量的情况下,使恢复系中载有Ｒｆｖ１的１Ｂ染色体（片段）加倍,如１Ａ缺体－１Ｂ四体能使Ｋ,Ｖ型杂种1Ｆ的育性完全恢复。     

The relation between pairing preference and chiasma frequency in tetrasomics of rye.

The association pattern of marked tetrasomes of Secale chromosome 1R at meiotic first metaphase was analyzed. Two of the four chromosomes were identical with terminal C-bands at both arms; the other two were also identical but lacked C-bands and were homologous or homeologous with the first two. Four different types of heterozygotes for 1R were studied: (i). autotetraploid hybrids between genetic variants within Secale cereale subsp. cereale, (ii). tetraploid hybrids between subspecies of Secale cereale, (iii). tetraploid hybrids between species of Secale, and (iv). autotetrasomes of S. cereale in a wheat background. Earlier observations that heterozygous associations (banded with unbanded) had consistently higher chiasma frequencies than homozygous associations were extended and confirmed. To analyze this phenomenon more closely, the possible relations between this correlation and several other meiotic phenomena were studied. For this analysis, three genetically different autotetraploid hybrids within S. cereale were selected that differed with respect to the relation between pairing type and chiasma frequency. Special attention was given to different patterns of interference and other meiotic phenomena in the two chromosome arms of chromosome 1R. No relations between such phenomena and the relation between pairing type and chiasma frequency could be established. A hypothesis is formulated assuming that long-distance homologue attraction is concentrated in a limited number of sites and that in different genotypes, different patterns of active sites are present. Moderately weak attraction sites can pair with strong homologous sites under favorable genetic conditions, but two weak sites cannot. Then, heterozygotes have more effective pairing initiation and consequently chiasma formation than homozygotes. Under less favorable conditions, only strong sites are effective, and then, homozygotes pair better, but the chiasma frequency is lower. A model of the forces involved in homologue attraction is presented.     

Ph1 gene derived from Aegilops speltoides induces homoeologous chromosome pairing in wide crosses of Triticum aestivum

The present study was conducted to investigate the effectiveness of the PhI gene transferred from Aegilops speltoides into bread wheat cultivar Chinese Spring (CS) in inducing homoeologous chromosome pairing in interspecific crosses using the Chinese Spring line, CS(PhI), carrying the gene. Chinese Spring, as well as CS(PhI), were crossed as female parents with three accessions of Ae. kotschyi (UUSS), one accession of Secale cereale (RR), two amphiploids of Triticum durum-Ae. caudata (AABBCC), and one amphiploid of Triticum durum-Ae. umbellulata (AABBUU). Meiotic metaphase I chromosome pairing was studied in all the interspecific crosses with CS as well as CS(PhI). There was significant increase in chiasma frequency in all the crosses with CS(PhI) over those with CS. The extent of induced homoeologous chromosome pairing by PhI in crosses of CS(PhI) with S. cereale was higher than with those of Ae. kotschyi, as indicated by higher chiasma frequency per pollen mother cell. Significant reduction in frequency of univalents and increase in bivalents (>14), multivalents, and chiasma frequency in crosses of amphiploids with CS(PhI) as compared to those of CS indicated induced homoeologous pairing between C and D, D and U, and C, D, and U genomes with AB genomes in the presence of PhI. The results of the present study unequivocally demonstrate the effectiveness of PhI gene transferred from Ae. speltoides in hexaploid wheat in inducing homoeologous chromosome pairing and suggest that the line CS(PhI) can be effectively used for precise transfer of useful alien genetic variations with least linkage drag.     

小麦叶锈病新抗源筛选

小麦叶锈病是小麦生产的主要病害之一,发病严重时往往导致大幅度减产。叶锈菌生理小种的变异易导致抗病基因抗性的丧失,因此不断获得新抗源对小麦抗病育种至关重要。小麦近缘植物中含有丰富的小麦育种所需的抗病基因。本研究从小麦-近缘植物双二倍体、附加系、代换系或易位系等创新种质中筛选出小麦叶锈病新抗源,为利用这些新抗源打下基础。苗期对116份供试材料人工接种美国堪萨斯州流行的小麦叶锈菌混合生理小种 (Lrcomp) ,其中部分材料人工接种09-9-1441-1等5个中国当前流行的叶锈菌生理小种进行抗性鉴定,筛选获得新抗源。116份种质中,31份免疫、近免疫或高抗Lrcomp。含有希尔斯山羊草、尾状山羊草、拟斯卑尔脱山羊草、两芒山羊草、卵穗山羊草、沙融山羊草、柱穗山羊草、顶芒山羊草、小伞山羊草、偏凸山羊草、中间偃麦草、茸毛偃麦草、长穗偃麦草、粗穗披碱草、栽培黑麦、非洲黑麦、提莫菲维染色质的部分种质免疫或高抗Lrcomp,而含二角山羊草、无芒山羊草、沙生冰草、多年生簇毛麦和一年生簇毛麦染色质的种质表现中感至高感Lrcomp。希尔斯山羊草4S染色体、尾状山羊草C#1和D#1染色体和两芒山羊草、顶芒山羊草中可能含有未被报道的抗Lrcomp的新基因,值得进一步向小麦转育。小麦-粗穗披碱草1HtS.1BL罗伯逊易位系对Lrcomp及 09-9-1441-1和09-9-1426-1等5个中国当前流行叶锈菌生理小种近免疫,值得利用染色体工程等方法获得小片段抗病易位系应用于我国小麦抗叶锈育种。     

Creating new forms of 4x, 6x and 8x primary triticale associating both complete R and D genomes

Summary Strains of Aegilops squarrosa L. and Ae. ventricosa L. were pollinated either by Secale cereale L. or tetraploid triticale. Using in vitro culture of immature F1 embryos, the four corresponding hybrids were obtained. Successful doubling occurred following colchicine treatment, leading to the creation of new amphidiploid structures (C1 plants). These correspond to primary triticale forms involving, at three different levels of ploidy, both R and D full complements. The various combinations were compared for their response at successive steps of the process. Crosses involving Ae. squarrosa present a higher fruit setting than those with Ae. ventricosa, which in contrast yield colchicine treated-plants with better grain fertility. Experimental data on the cytological behaviour and fertility of colchicine-treated as well as amphidiploid plants are presented. The importance of this material in triticale breeding is discussed.     

Isoenzymes of aspartate aminotransferase in perennial and annual rye and their hybrids.

Aspartate aminotransferase patterns were screened in a collection of rye genotypes that included 24 accessions of wild perennial rye (Secale montanum Guss.), 6 accessions of cultivated perennial Derzhavin and Tsitsin rye (Secale cereale x S. montanum), 15 accessions of winter and spring rye cultivars (S. cereale L.), and 9 accessions of perennial and annual rye genotypes bred from S. montanum ssp. kuprijanovii, Derzhavin rye, and winter rye for their resistance to fungal diseases. Aspartate aminotransferase is coded for by four loci. The data fit the model where AAT 1/4 is coded by Aat 1 and Aat 4, two duplicate loci, with null and two active alleles for each locus, alleles 1 and 3 for locus Aat 1 and alleles 2 and 4 for locus Aat 4; dimeric AAT 1/4 enzyme molecules are the products of both intralocus and interloci complementation. Allele 1 of Aat 1 was the most prominent in the isoenzyme patterns of the rye species. Alleles null and 2 of Aat 4 were twice as frequent in the perennial rye accessions, including Derzhavin and Tsitsin rye, than in winter and spring rye. In contrast, allele 4 of Aat 4 was characteristic of S. cereale. Within the screened collection, locus Aat 2 was monomorphic. Among three alleles of Aat 3, allele 2 dominated isoenzyme profiles of both rye species, whereas the other two alleles were species-specific: allele 1 was characteristic of S. montanum and allele 3 was found only in S. cereale. Key words : rye, Secale cereale, Secale derzhavinii, Secale montanum, aspartate aminotransferase, isoenzymes, perennial habit, polymorphism.     

普通小麦×根茎冰草×黑麦三属杂种自交可育性的细胞学机理

普通小麦（ＴｒｉｔｉｃｕｍａｅｔｉｖｕｍＬ．,２ｎ＝６ｘ＝４２;ＡＡＢＢＤＤ）和根茎冰草（ＡｇｒｏｐｙｒｏｎｍｉｃｈｎｏｉＲｅｓｈｅｖ．,２ｎ＝４ｘ＝２８;ＰＰＰＰ）间的Ｆ１杂种（２ｎ＝５ｘ＝３５：ＡＢＤＰＰ）与两个黑麦（ＳｅｃａｌｅｃｅｒｅａｌｅＬ．,２ｎ＝２ｘ＝１４;ＲＲ）品种杂交,产生了自交可育的三属杂种。经细胞学研究表明,这种自交可育性是由于在某些细胞中通过两种方式发生了第一次减数分裂的失败,即单价染色体在赤道板发生分裂和单价染色体在一极的聚集,从而异致了有功能的雌、雄配子的形成。有功能配子的形成受染色体配对频率、基因型和环境状况的影响。冰草属的Ｐ染色体组存在染色体分离的控制基因,从而引起含有冰草属的杂种能够形成有功能的配子且自交可育。     

Origin of B chromosomes in cultivated rye.

Cultivated rye (Secale cereale) and its weedy relative (S. segetale) carry B chromosomes. The B chromosomes are known to be morphologically alike at somatic metaphase and they are of the standard type in natural populations. To clarify the cytogenetic relationship between the standard B chromosomes of S. cereale and those of S. segetale, we made four crosses between Afghan S. segetale with two standard B chromosomes as a pistillate parent and Turkish, Iranian, Korean, and Japanese S. cereale, all with two standard B chromosomes as pollen parents. We observed the pairing of B chromosomes at diakinesis in pollen mother cells in all F1 hybrids with four standard B chromosomes, two from each of the pistillate and the pollen parents. The degree of pairing of B chromosomes in all F1 hybrids with four standard B chromosomes was similar to or somewhat lower than, that in parental strains with four standard B chromosomes. These results showed that the standard B chromosomes in S. segetale from Afghanistan are homologous with those in S. cereale from Turkey, Iran, Korea, and Japan. We therefore propose monophyletic origin of the standard B chromosomes in S. segetale and S. cereale.     

Mechanisms and inheritance of first division restitution in hybrids of wheat, rye, and Aegilops squarrosa.

First division restitution (FDR) in intergeneric Triticeae hybrids provides an important meiotic mechanism for the production of amphidiploids without the use of colchicine and similar chemicals. The genetic controls of FDR were investigated by examining microsporogenesis and fertility in F1 hybrids of two- and three-way crosses of durum wheat (Triticum turgidum L. var. durum) cultivars Langdon (LDN) and Golden Ball (GB), 'Gazelle' rye (Secale cereale L.), and one accession (RL5286) of Aegilops squarrosa L. The results from two-way crosses indicated that the first meiotic division varied, depending on the hybrid. GB crossed with Ae. squarrosa developed tripolar spindles and prevented congregation of chromosomes at the equatorial plate. The hybrid of GB with rye had a delayed first division. But, the hybrids of LDN with both Ae. squarrosa and rye had a high frequency of FDR. Analysis from the three-way crosses indicated that inheritance in rye crosses differed from those with Ae. squarrosa. FDR segregated in a 1:1 ratio in the rye cross, suggesting that the FDR is controlled by a single gene from LDN. However, FDR fit a 1:3 ratio in the three-way crosses with Ae. squarrosa. Cytological data suggested that tripolar spindles are a major factor preventing FDR in Ae. squarrosa crosses. Some progenies from the three-way cross with rye had a high frequency of monads that resulted from second division failure of FDR cells.     

Molecular Cytogenetic Identification of Triticum aestivum-Secale cereale Substitution and Addition Lines

Two substitution lines, designated as 930498 and 930483, and one addition line, designated as 930029, via Fo immature embryo culture of Triticum aestivum x octoploid triticale ( x Triti-cosecale Wittmack) were identified. Fluorescence in situ hybridization (FISH) using total genomic DNA of rye ( Secale cereale L. ) as probe corroborated the existence of rye chromosomes, further confirmed through chromosome paring at meiotic metaphase 1, C-banding and glutenin SDS- PAGE. The results demonstrated that the two substitution lines are ID/IR, and the addition line is also IR addition. Rye chromosomes that are distinct to the red-colored wheat chromosomes appear yellow-green at mitotic metaphase after FISH.     

Discrimination of Repetitive Sequences Polymorphism in Secale cereale by Genomic In Situ Hybridization-Banding

Genomic in situ hybridization banding (GISH-banding), a technique slightly modified from conventional GISH, was used to probe the Chinese native rye (Secale cereale L.) DNA, and enabled us to visualize the Individual rye chromosomes and create a universal reference karyotype of the S. cereale chromosome 1R to 7R. The GISH-banding approach used in the present study was able to discriminate S. cereale chromosomes or segments in the wheat (Triticum aeativum L.) background, including the Triticale, wheat-rye addition and translocation lines. Moreover, the GISH-banding pattern of S.cereale subsp. Afghanicum chromosomes was consistent with that of Chinese native rye cv. Jingzhou rye; whereas the GISH-banding pattem of Secale vavilovli was different from that of S. cereale, indicating that GISH-banding can be used to study evolutionary polymorphism in species or subspecies of Secale. In addition, the production and application of GISH-banding to the study of adenine-thymine-riched heterochromatin is discussed.     

Evaluation of phylogenetic relationships between five polyploid Aegilops L. species of the U-genome cluster by means of chromosomal analysis

Four tetraploid (Aegilops ovata, Ae. biuncialis, Ae. columnaris, and Ae. triaristata) and one hexaploid (Ae. recta) species of the U-genome cluster were studied using C-banding technique. All species displayed broad C-banding polymorphism and high frequency of chromosomal rearrangements. Chromosomal rearrangements were represented by paracentric inversions and intragenomic and intergenomic translocations. We found that the processes of intraspecific divergence of Ae. ovata, Ae. biuncialis, and Ae. columnaris were probably associated with introgression of genetic material from other species. The results obtained confirmed that tetraploid species Ae. ovata and Ae. biuncialis occurred as a result of hybridization of a diploid Ae. umbellulata with Ae. comosa and Ae. heldreichii, respectively. The dissimilarity of the C-banding patterns of several chromosomes of these tetraploid species and their ancestral diploid forms indicated that chromosomal aberrations might have taken place during their speciation. Significant differences of karyotype structure, total amount and distribution of C-heterochromatin found between Ae. columnaris and Ae. triaristata, on the one hand, and Ae. ovata and Ae. biuncialis, on the other, evidenced in favor of different origin of these groups of species. In turn, similarity of the C-banding patterns of Ae. columnaris and Ae. triaristata chromosomes suggested that they were derived from a common ancestor. A diploid species Ae. umbellulata was the U-genome donor of Ae. columnaris and Ae. triaristata; however, the donor of the second genome of these species was not determined. We assumed that these tetraploid species occurred as a result of introgressive hybridization. Similarity of the C-banding patterns of chromosomes of Ae. recta and its parental species Ae. triaristata and Ae. uniaristata indicated that the formation of the hexaploid form was not associated with large modifications of the parental genomes.     

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。     

Ultrastructural Changes in Chloroplasts of Cucumis sativus L. and Secale cereale L. during Low-Temperature Hardening

Russian Journal of Plant Physiology - Chloroplast ultrastructural changes were investigated in chilling-sensitive (cucumber, Cucumis sativus L.) and cold-tolerant (winter rye, Secale cereale L.)...