Genetic diversity and phylogeny in Hystrix (Poaceae, Triticeae) and related genera inferred from Giemsa C-banded karyotypes

The phylogenetic relationships of 15 taxa from Hystrix and the related genera Leymus (NsXm), Elymus (StH), Pseudoroegneria (St), Hordeum (H), Psathyrostachys (Ns), and Thinopyrum (E) were examined by using the Giemsa C-banded karyotype. The Hy. patula C-banding pattern was similar to those of Elymus species, whereas C-banding patterns of the other Hystrix species were similar to those of Leymus species. The results suggest high genetic diversity within Hystrix, and support treating Hy. patula as E. hystrix L., and transferring Hy. coreana, Hy. duthiei ssp. duthiei and Hy. duthiei ssp. longearistata to the genus Leymus. On comparing C-banding patterns of Elymus species with their diploid ancestors (Pseudoroegneria and Hordeum), there are indications that certain chromosomal re-arrangements had previously occurred in the St and H genomes. Furthermore, a comparison of the C-banding patterns of the Hystrix and Leymus species with the potential diploid progenitors (Psathyrostachys and Thinopyrum) suggests that Hy. coreana and some Leymus species are closely related to the Ns genome of Psathyrostachys, whereas Hy. duthiei ssp. duthiei, Hy. duthiei ssp. longearistata and some of the Leymus species have a close relationship with the E genome. The results suggest a multiple origin of the polyploid genera Hystrix and Leymus.     

Comparison of the Giemsa C-banded and N-banded karyotypes of twoElymus species,E. dentatus andE. glaucescens (Poaceae: Triticeae)

The karyotypes ofElymus dentatus from Kashmir andE. glaucescens from Tierra del Fuego, both carrying genomesS andH, were investigated by C- and N-banding. Both taxa had 2n = 4x = 28. The karyotype ofE. dentatus was symmetrical with large chromosomes. It had 18 metacentric, four submetacentric and six satellited chromosomes. The karyotype ofE. glaucescens resembled that ofE. dentatus, but a satellited chromosome pair was replaced by a morphologically similar, non-satellited pair. The C-banding patterns of both species had from one to five conspicuous and a few inconspicuous bands per chromosome. N-banding differentiated the chromosomes of the constituent genomes by producing bands in theH genome only. TheS genomes of both species were similar with five metacentric and two satellited chromosomes having most conspicuous C-bands at telomeric and distal positions. They resembled theS genome of the genusPseudoroegneria. TheH genomes had four similar metacentric and two submetacentric chromosomes. The seventhH genome chromosome ofE. dentatus was satellited, that ofE. glaucescens nonsatellited, but otherwise morphologically similar. The C-bands were distributed at no preferential positions. TheH genome ofE. dentatus resembles theH genomes of some diploidHordeum taxa.     

Giemsa C-banded karyotypes of diploid and tetraploidHordeum bulbosum (Poaceae)

The similar-looking basic genomes ofHordeum bulbosum (2x and 4x) have five rather similar metacentric, one submetacentric, and one satellited choromosome. C-banding patterns are characterized by one or two centromeric, or juxtacentromeric, small to larger bands in most chromosomes, by bands at the nucleolar organizers, by small or very small telomeric bands, and by the nearly complete lack of intercalary bands. Banding pattern polymorphism is widespread. Banding patterns supported by chromosome morphology enable identification of homologues, and discrimination between non-homologues inH. bulbosum (2x). The C-banded karyotype ofH. bulbosum (4x) supports an autopolyploid origin, but it was possible to identify only homologues of submetacentrics and SAT-chromosomes.     

Giemsa C-banded karyotypes inCapsicum (Solanaceae)

Giemsa C-banding is applied for the first time inCapsicum, allowing preliminary karyotype differentiation of six diploid species. Comparison of interphase nuclei and heterochromatic C-bands reveals striking differences between taxa and contributes to their taxonomic grouping. Therefore, C-banding appears to be a powerful tool for the cytogenetics and karyosystematics of the genus. Banding patterns are characterized by the omnipresence of centromeric bands and a variable number of smaller to larger distal bands, with the addition of intercalary bands in some cases. Satellites are always C-positive. Relationships between species and possible trends of karyotype evolution are discussed, with special reference to the origin of x = 13 from x = 12 and the increase of heterochromatin, regarded as advanced features.Chromosome studies inCapsicum (Solanaceae), III. For the first and the second part seeMoscone (1990, 1993).     

Giemsa C-banded karyotypes in Serupius L. (Orchidaceae)

Giemsa C-banding is utilized for the first time to characterize eight taxa of the genus Serapias . Heterochromatin distribution indicated that the Serapias species form a very homogeneous group. All the species possess chromosome pairs with similar heterochromatin patterns. C-banding showed conspicuous bands located around the centromeres, with some het-erochromatic short arms. There was more heterochromatin in S. apulica and S. nurrika than in the other taxa. Extensive centromeric heterochromatin may indicate recent structural rearrangements in the chromosome complement. Taken altogether, karyomorphology indicates a rather recent origin for the genus Serapias , which might also account for the small amount of interspecific variation observed.     

Hystrix patula与Pseudoroegneria libanotica属间杂种的细胞学研究

为研究猬草Hystrixpatula的染色体组组成,进行了H.patula与Pseudoroegnerialibanotica的人工杂交,获得杂种F1,观察了亲本和杂种F1花粉母细胞减数分裂染色体配对行为。杂种F1染色体配对较高,84%的细胞形成7个或7个以上二价体,其构型为6.08Ⅰ+7.48Ⅱ,C-值为0.69。结果表明,H.patula含有St染色体组。     

Giemsa C-banded karyotypes ofAllium ericetorum andA. kermesinum (Alliaceae)

The widely distributedAllium ericetorum and the local endemic of the Steiner Alps (Slovenia),A. kermesinum, are two closely related species of sect.Rhizirideum, whose main distinguishing character is perianth colour. To obtain further evidence for species separation, karyotype morphology and C-banding patterns were examined in 10 populations. The chromosome number was 2n = 16. In some populations ofA. ericetorum a B-chromosome occurred. Arm and satellite lengths and C-banding patterns were subjected to cluster analysis. Three different karyotype classes were observed and described. Karyotypes did not clearly discriminate between plants with different colours of perianth segments and therefore did not provide evidence for a taxonomic separation ofA. ericetorum and A. kermesinum. There is polymorphism in number and patterns of C-bands within the populations. No correlation between B-chromosomes and particular banding patterns was observed.     

Meiotic pairing behaviour reveals differences in genomic constitution between Hystrix patula and other species of the genus Hystrix Moench (Poaceae, Triticeae)

Interspecific and intergeneric hybridizations were carried out to evaluate the genomic relationships among species of Hystrix Moench and to study the relationships between Hystrix species and Psathyrostachys huashanica Keng (2n=2x=14, Ns^h). Meiotic pairing in hybrids of Hystrix duthiei ssp. duthiei × P. huashanica (2n=3x=21), Hystrix duthiei ssp. longearistata × P. huashanica (2n=3x=21) and H. patula × P. huashanica (2n=3x=21) averaged 5.18, 5.11 and 0.29 bivalents per cell, while H. patula × H. duthiei ssp. longearistata (2n=4x=28) averaged 25.36 univalents and 1.32 bivalents per cell, respectively. The results indicate that (i) H. duthiei ssp. duthiei and H. duthiei ssp. longearistata have one set of Ns genome from Psathyrostachys; (ii) H. patula has no Ns genome; (iii) genomes of H. duthiei ssp. duthiei and H. duthiei ssp. longearistata are non-homologous to those of H. patula. The genomic relationships between H. patula and other Hystrix species are also discussed.     

Genome analysis of species in the genus Hystrix (Triticeae; Poaceae)

Genomic in situ hybridisation (GISH) and Southern genomic hybridisation were applied in order to gain further knowledge regarding generic delimitation of the genus Hystrix as well as to clarify the genomes of the Hystrix species H. patula, H. longearistata, H. coreana, H. duthiei and H. komarovii. The hybridisation intensity of different genomic probes was compared among the Hystrix species and with other Triticeae species. The Southern- and GISH results confirm that H. patula contains the StH genome and show that H. komarovii most likely has a variant of this StH genome. The other Hystrix species under study, i.e. H. longearistata, H. coreana and H. duthiei, contain an Ns basic genome, and most probably two variants of this basic genome, Ns ¹ Ns ² . The genus Hystrix is thus not a monophyletic group of species.     

小麦族下Hystrix longearistata和Hystrix duthiei的生物系统学研究

对Hystrix duthiei、H．longearistata和它们的人工种间杂种花粉母细胞减数分裂染色体配对行 为、繁育特征和形态特征进行了比较分析,结果表明：(1)这两个分类单位形态差异较小,H．longearista－ ta的外稃芒较长,叶片较宽,每小穗具2--3个小花;H．duthiei的外稃芒较短,叶片较窄,每小穗具1～2 个小花。(2)它们很容易杂交,杂种F_l染色体配对频率很高,为13～14个二价体。(3)亲本种花粉育 性和结实性正常,杂种F_l花粉育性较低,结实性较差。(4)H．longearistata和H．duthiei亲缘关系很 近,是同一物种。由于地理分布和生境的差异,使它们在形态上开始分异,并出现一定程度的生殖隔离。把H．longearistata处理为Hystrix duthiei的一亚种是合理的。     

Meiotic analysis of the interspecific and intergeneric hybrids between Hystrix patula Moench and H. duthiei ssp. longearistata, Pseudoroegneria, Elymus, Roegneria, and Psathyrostachys species (Poaceae, Triticeae)

Interspecific and intergeneric hybridizations were carried out in an investigation of genome homology between Hystrix patula and other species of Hystrix , as well as the generic relationships between H. patula and its related species. Meiotic pairing in the hybrids H. patula  ×  H. duthiei ssp. longearistata (Ns–), H. patula  ×  Pseudoroegneria spicata (St), H. patula  ×  Pse. libanotica (St), Elymus sibiricus (StH) ×  H. patula , H. patula  ×  E. wawawaiensis (StH), Roegneria ciliaris (StY) ×  H. patula , H. patula  ×  R. grandis (StY), and H. patula  ×  Psathyrostachys huashanica (Ns^h) averaged 1.32, 6.53, 5.62, 10.08, 12.83, 3.57, 3.98, and 0.29 bivalents per cell, respectively. The results indicate that: (1) H. patula has no genome homology with H. duthiei ssp. longearistata or the Ns genome from Psathyrostachys ; (2) H. patula contains the same StH genomes as the Elymus species, and the St genome is homologous to the genome of Pse. spicata and Pse. libanotica ; and (3) H. patula has a low genome affinity with the StY genomes of Roegneria . Therefore, it is reasonable to treat H. patula Moench as E. hystrix L.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 213–219.     

Biosystematic studies on Hystrix longearistata from Japan and Hystrix duthiei from China (Poaceae: Triticeae)

Morphological comparison, cytogenetic study and fertility analysis of Hystrix duthiei (2n = 28) from China, Hystrix longearistata (2n= 28) from Japan and their artificial hybrids were carried out. Morphologically H. duthiei was similar to H. longearistata. H. longearistata had longer lemma awn, wider leaf and 2～3 florets per spikelet, while H. duthiei had 1～2 florets per spikelet. These two taxa can be easily crossed. F_l hybrids showed very high degree of bivalent pairing (13～14 bivalents) at the metaphase- I of meiosis. No multivalents were found. The fertility of pollen and seed set of the parents were normal, while the F_l hybrids were of only partial fertility. H. longearistata was closely related to H. duthiei. They should be included in the same species. Because of the differences of their distributions and habitats, some morphological divergency and a little sterility barrier have had appeared between them. It is reasonable to treat Hystrix longearistata as a sub-species of Hystrix duthiei .     

利用RAPD特异标记分析东北猬草染色体组成

选用5个染色体组特异的RAPD引物(St、H、Ns、Ee、Eb),对东北猬草[Hystrix komarovii (Roshev.) Ohwi]等5个猬草属及其8个近缘属物种进行PCR扩增,以探讨东北猬草的染色体组组成.结果显示:Hy.komarovii具有Ns染色体组特异的RAPD标记,而没有St、H、Ee和Eb特异的RAPD标记.表明Hy.komarovii含有Ns染色体组,而不含St和H染色体组,认为其染色体组组成可能与Hy.duthiei、Hy.coreana和Leymus arenarius一样,具有NsXm染色体组.根据染色体组分类原理,支持将东北猬草归于赖草属中.     

Comparison of the Giemsa C-banded karyotypes of the three subspecies ofPsathyrostachys fragilis,subspp.villosus (2x),secaliformis (2x, 4x), andfragilis (2x) (Poaceae), with notes on chromosome pairing

The karyotypes of diploidP. fragilis subsp.villosus (2n = 2x = 14) and tetraploid subsp.secaliformis (2n = 4x = 28) were studied by Giemsa C- and N-banding, and AgNO₃ staining and compared with the karyotype of subsp.fragilis (2x). The complements of subsp.villosus and subsp.fragilis were similar, with 8 metacentric and 6 SAT-chromosomes, one metacentric and two submetacentric pairs, with small to minute, polymorphic, heterochromatic satellites. The complement of subsp.secaliformis on the whole agreed with a doubling of the complement of diploidP. fragilis, suggesting autopolyploidy. Only the presence of 12 nucleoli in interphases identified 6 SAT-chromosome pairs. In subsp.villosus one or two extra micronucleoli indicated a chromosome pair with very low nucleolusforming activity, bringing the number of SAT-chromosome pairs to 4. This number may be a characteristc ofPsathyrostachys. Besides very small, inconsistently observed bands, the C-banding pattern consisted of 0–3 small bands per chromosome at intercalary and terminal locations, and at NORs. The level of banding pattern polymorphism was low, but enough to indicate that the taxa are outbreeders. Similarities in chromosome morphology and C-banding patterns identified homology of all chromosomes of subsp.villosus, but for 12 pairs only in subsp.secaliformis. Between plants, reliable identification of homology and homoeology (subsp.secaliformis) was possible only for the SAT-chromosomes and the shortest metacentrics. Chromocentres were very small and the amount of constitutive heterochromatin was low. N-banding stained chromosomes uniformly. The basic karyotypes of theP. fragilis taxa were similar to those ofP. juncea, P. lanuginosa, andP. stoloniformis supporting a close relationship and the presence of a common genome, N. NORs had different nucleolus-forming activities. Meiotic analysis demonstrated a high level of bivalent pairing in the three taxa. A chromosomal rearrangement was suggested in subsp.villosus. The low multivalent frequency in subsp.secaliformis indicates the presence of a pairing regulation mechanism. The majority of chiasmata were interstitial. Pollen grain size discriminated between diploid and tetraploid taxa. The existence of a diploid cytotype of subsp.secaliformis is supported by pollen measurements of herbarium material.     

Phylogeny of Hystrix and related genera (Poaceae: Triticeae) based on nuclear rDNA ITS sequences

The taxonomic status of Hystrix and phylogenetic relationships among Hystrix and its related genera of Pseudoroegneria (St), Hordeum (H), Psathyrostachys (Ns), Elymus (StH), Leymus (NsXm), Thinopyrum bessarabicum (E(b)) and Lophopyrum elongatum (E(e)) were estimated from sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. The type species of Hystrix, H. patula, clustered with species of Pseudoroegneria, Hordeum, Elymus, Th. bessarabicum and Lo. elongatum, while H. duthiei ssp. duthiei, H. duthiei ssp. longearistata, H. coreana and H. komarovii were grouped with Psathyrostachys and Leymus species. The results indicate that: (i) H. patula is distantly related to other species of Hystrix, but is closely related to Elymus species; (ii) H. duthiei ssp. duthiei, H. duthiei ssp. longearistata, H. coreana and H. komarovii have a close affinity with Psathyrostachys and Leymus species, and H. komarovii might contain the NsXm genome of Leymus; and (iii) the St, H and Ns genomes in Hystrix originate from Pseudoroegneria, Hordeum and Psathyrostachys, respectively, while the Xm in Hystrix and Leymus has a complex relationship with the E or St genomes. According to the genomic system of classification in Tiritceae, it is reasonable to treat Hystrix patula as Elymus hystrix L, and the other species of Hystrix as species of a section of Leymus, Leymus Sect. Hystrix.     

利用RAPD分析披碱草属、鹅观草属和猬草属模式种的亲缘关系

利用随机扩增多态性DNA（RAPD）技术对小麦族披碱草属、鹅观草属和猬草属3个属的模式种进行了基因组DNA多态性分析。42个引物产物的290条谱带中,257条（88.62%)表现出多态性,说明披碱草属、鹅观草属和猬草属3个属的模式种间具有丰富的遗传多样性。利用290个RAPD标记,计算材料间Nei氏遗传相似性系和遗传距离,在NTSYS程序中利用UPGMA进行聚类。结果表明,Elymus sibiricus种不同居群间的遗传差异较小,遗传距离在0.097-0.180之间。E.sibiricus,Roegneria caucasica和Hystrix patula的种间遗传差异明显,遗传距离在0.458-0.605之间。H.patula与E.sibiricus的亲缘关系较近。R.caucasica与E.sibiricus的亲缘关系较远。     

Taxonomy ofHordeum caespitosum,H. jubatum,andH. lechleri (Poaceae: Triticeae)

Hordeum caespitosum Scribner,H. jubatum L., andH. lechleri (Steudel)Schenck are very similar in appearance and therefore until recently were mostly not recognized as separate entities. The first two are tetraploid and natives to North America, but the second occurs naturally in eastern Siberia and has been introduced in Europe and South America and may become a cosmopolitan weed. The third is hexaploid and South American. This study analyses their morphological diversity by means of selected multivariate techniques in order to determine if there is justification to recognize them as three separate morphological species. Logistic discrimination, although based on a reduced set of characters, yielded the highest percent of correct assignments. A linear discriminant function is provided and validated by 100 bootstrap repeats. Canonical discriminant analysis indicated three groups. It is subsequently concluded that the three are separate morphological species. Although a linear discriminant function is given, a traditional identification key is provided based on the palea length and triad (the group of three spikelets at each rachis node) length.     

鹅观草属、披碱草属、猬草属和仲彬草属物种的RAMP分析及系统学意义

对鹅观草属、披碱草属、猬草属和仲彬草属4属23个物种进行了RAMP分析。结果表明属间变异极大,多态性极高。31个引物组合产生的286条DNA扩增片段均具有多态性。聚类分析显示鹅观草属、披碱草属、猬草属和仲彬草属物种各自聚为一类;Roegneria alashanica、R．elytrigioides和R．magnticaespes聚类在一起;猬草属的模式种Hystrix patula与披碱草属物种聚类在一起,而Hystrix duthiei和H．longearistata单独聚为一类;形态相似、染色体组相同、地理分布一致的物种聚类在一起。本研究结果基本上同形态学和细胞学研究结果相吻合,将鹅观草属、披碱草属和仲彬草属作为属分类等级处理比较恰当,而猬草属的系统地位有待进一步确认。RAMP标记可作为评价多年生小麦族物种遗传多样性和亲缘关系的一种分子标记技术。     

长芒猬草与华山新麦草属间杂种的形态学和细胞学研究

为研究长芒猬草Hystrix duthiei ssp．longearistata的染色体组成,将其与华山新麦草Psathyrostachys huashanica进行了人工杂交,获得杂种F₁。对亲本及杂种F₁,花粉母细胞减数分裂染色体配对行为、繁育 特性和形态特征进行了比较分析。结果表明：杂种F₁的许多形态特征介于父母本之间,花粉完全不育, 结实率为0;杂种F₁花粉母细胞减数分裂中期Ⅰ染色体配对较高,55.12％的细胞形成5个或6个二价 体,其构型为：9.83Ⅰ+5.46Ⅱ+0.07Ⅲ,C-值为0.57。以上结果表明H．duthiei ssp．Longearistata含有Ns染色体组。本文还讨论了Hystrix与Leymus的关系。