Reinhard M. Fritsch

Phylogenetic analysis of Allium subg. Melanocrommyum infers cryptic species and demands a new sectional classification

Allium subgenus Melanocrommyum (Alliaceae) from Eurasia comprises about 150 mostly diploid species adapted to arid conditions. The group is taxonomically complicated with different and contradictory taxonomic treatments, and was thought to include a considerable number of hybrid species, as the taxa show an admixture of assumed morphological key characters. We studied the phylogeny of the subgenus, covering all existing taxonomic groups and their entire geographic distribution. We analyzed sequences of the nuclear rDNA internal transcribed spacer region (ITS) for multiple individuals of more than 100 species. Phylogenetic analyses of cloned and directly sequenced PCR products confirmed the monophyly of the subgenus, while most sections were either para- or polyphyletic. The splits of the large sections are supported by differences in the anatomy of flower nectaries. ITS data (i) demand a new treatment at sectional level, (ii) do not support the hypotheses of frequent gene flow among species, (iii) indicate that multiple rapid radiations occurred within different monophyletic groups of the subgenus, and (iv) detected separately evolving lineages within three morphologically clearly defined species (cryptic species). In two cases these lineages were close relatives, while in Allium darwasicum they fall in quite different clades in the phylogenetic tree. Fingerprint markers show that this result is not due to ongoing introgression of rDNA (ITS capture) but that genome-wide differences between both lineages exist. Thus, we report one of the rare cases in plants where morphologically indistinguishable diploid species occurring in mixed populations are non-sister cryptic species.

Analysis of molecular data of Arabidopsis thaliana (L.) Heynh. (Brassicaceae) with Geographical Information Systems (GIS)

A Geographical Information System (GIS) is used to analyse allelic information of 13 sequenced loci of natural populations of Arabidopsis thaliana and to identify geographical structures. GIS provides tools for visualization and analysis of geographical population structures using molecular data. The geographical distribution of the number of variable positions in the alignments, the distribution of recombinant sequence blocks, and the distribution of a newly defined measure, the differentiation index, are studied. The differentiation index is introduced to measure the sequence divergence among individual plants sampled from various geographical localities. The numbers of variable positions and the differentiation index are also used for a metadata analysis covering about 26 kb of the genome. This analysis reveals, for the first time, differences in DNA sequence structures of geographically different populations of A. thaliana. The broadly defined west Mediterranean region consists of accessions with the highest numbers of polymorphic positions followed by the west European region. The GIS technology Kriging is used to define Arabidopsis specific diversity zones in Europe. The highest genetic variability is observed along the Atlantic coast from the western Iberian Peninsula to southern Great Britain, while lowest variability is found in central Europe.

Phylogenetic relationships of wild and cultivated species of Allium section Cepa inferred by nuclear rDNA ITS sequence analysis

Allium section Cepa consists of 12 species most of which are used by humans as condiment, vegetable or medicinal plants. Common onion (Allium cepa) and bunching onion (A. fistulosum) are cultivated species while all others are locally collected from the wild. Although common onion is the most important crop within Allium, its wild progenitor and origin are still not clear. We analyzed the phylogeny of Allium section Cepa using sequences of the nuclear ribosomal DNA internal transcribed spacer (ITS) region of 36 accessions representing eleven species of section Cepa, together with eight outgroup species with phenetic, cladistic, and model-based algorithms. These analyses confirmed section Cepa to be monophyletic and revealed three species groups within the section. These are (i) A. altaicum/A. fistulosum, (ii) A. farctum/A. roylei/A. asarense/A. cepa/A. vavilovii, and (iii) A. galanthum/A. oschaninii/A. praemixtum/A. pskemense. While the first two groups were statistically well supported for the last group support was low, although it resulted in all phylogenetic analyses conducted. Tree and network-based analyses grouped A. cepa within A. vavilovii, indicating the latter to be progenitor of the common onion. However, also an origin of A. cepa through hybridization of A. vavilovii with A. galanthum or A. fistulosum seems possible. We argue that a subdivision of section Cepa in subsections Cepa and Phyllodolon, although possible from our data, as well as the formal description of alliances do not seem reasonable in a small group of species.

Allium vavilovii M. Popov et Vved. and a new Iranian species are the closest among the known relatives of the common onion A. cepa L. (Alliaceae)

A wild onion species from Karaj valley east of Tehran istaxonomically described as Allium asarense R. M.Fritsch et Matin. Sharing the bubble-like inflated lower scapewith A. vavilovii, the newspecies differs by semi-cylindrical leaves and small flowerswith translucent greenish-yellow tepals from all other knownspecies of Allium sect.Cepa. Molecular data suggest a closerelationship to A. cepa(but to a lesser degree than A.vavilovii) and indicate a still weakerphylogenetic connection of A.oschaninii to the common onion. The questionabout the possible wild ancestor of A.cepa is discussed against this background, and akey for determination of the Oschaninii-alliance of sect.Cepa is presented.

Four New Species of Allium (Alliaceae) from Iran

Four species of Allium from northwest Iran are described as new: Allium alamutense Razyfard, Zarre & R.M. Fritsch, A. kurdistanicum Maroofi & R.M. Fritsch, A. subakaka Razyfard & Zarre, and A. mahneshanense Razyfard, Zarre & R.M. Fritsch. A detailed description for each species, a table including the diagnostic morphological characters useful in separating these species from their relatives, images of type material and illustrations of flower parts as well as distribution maps are provided.

Comparative Analysis of Growth, Genome Size, Chromosome Numbers and Phylogeny of Arabidopsis thaliana and Three Cooccurring Species of the Brassicaceae from Uzbekistan

Contrary to literature data Arabidopsis thaliana was rarely observed in Middle Asia during a collection trip in 2001. Instead, three other Brassicaceae species were frequently found at places where A. thaliana was expected. To reveal reasons for this frequency pattern, we studied chromosome numbers, genome sizes, phylogenetic relationships, developmental rates, and reproductive success of A. thaliana, Olimarabidopsis pumila, Arabis montbretiana, and Arabis auriculata from Uzbekistan in two temperature treatments. There are little but partially significant differences between phenotypes. All studied species have very small genomes. The 1Cx-values of different genotypes within the sampled species are correlated with altitude. Developmental rates are also correlated with 1Cx-values. In our growth experiments, Arabidopsis had high seed sterility at higher temperature, which might be one reason for the rarity of A. thaliana in Middle Asia.

Allium Oriento-Iranicum (Alliaceae), a New Species from Iran

Allium oriento-iranicum Neshati, Zarre & R.M. Fritsch (Alliaceae) is described and illustrated as a new species from NE Iran. It belongs in sect. Megaloprason and is compared with other species in that section.

Phylogenetic relationships of ornamental species in Allium L. subg. Melanocrommyum (Webb et Berthel.) Rouy (Alliaceae)

About 30 ornamental Allium species are affiliated to nine sections of subg. Melanocrommyum. Recent molecular investigations (sequences of the Internal Transcribed Spacer of nuclear DNA and the trnL-trnF region of chloroplast DNA) showed that most sections are either para- or polyphyletic. Therefore, genetic relationship of these ornamental taxa cannot simply be deduced from affiliation to identical sections. After a brief historical outline, the current affiliation is discussed in connection with relevant molecular data. Molecular data confirmed these pairs of very closely related species: A. nigrum / A. atropurpureum; A. orientale / A. cyrilli; A. alexeianum / A. nevskianum; A. stipitatum / A. altissimum; but their next related species are mostly other ones than formerly deduced from morphological similarities. Allium hollandicum is a species-pair only with Iranian accessions of A. stipitatum and might be of Iranian offspring. A remarkable genetic diversity related to geography was found in A. rosenorum / A. jesdianum, and A. stipitatum. Allium akaka in the wide sense consists of several taxa. Among the material of A. darwasicum two genetically different entities were detected. Unexpectedly, A. giganteum, A. macleanii, A. protensum, A. caspium, A. lipskyanum, A. aflatunense, A. backhousianum, A. karataviense, A. cupuliferum, A. cristophii, A. regelii, A. cardiostemon, A. aschersonianum A. schubertii, A. fetisowii, and A. decipiens occupy phylogenetic positions rather isolated from their morphologically most similar species.

Pollen morphology of some Allium L. species (Alliaceae) from Iran

Neshati, F., Fritsch, R. M. & Zarre, Sh.: Pollen morphology of some Allium L. species (Alliaceae) from Iran. — Bot. Jahrb. Syst. 127: 433–451. 2009. — ISSN 0006-8152. Pollen grains of 30 Allium species, representing 15 of the currently recognized sections distributed in Iran, were examined by light and scanning electron microscopy. The pollen grains were eutectate, mono-anasulcate and heteropolar, 22 to 38 μm long (equatorial axis E) and 13 to 24 μm wide (polar axis P), the form was peroblate to suboblate (mean of P/E ratio 0.46 to 0.69) and in polar view boat-shaped. Sculpturing was rugulate to microrugulate and perforate, with transitions to striate condition in subg. Melanocrom myum and a few more species. Clear striate sculpturing occurred only in A. helicophyllum. Our data confirmed an elongated sulcus continuing to the proximal side and ending before the proximal pole to be apparently a synapomorphy of sect. Allium only. The relatively short sulcus of A. borszczowii can be accepted as palynological evidence that this species does not belong to sect. Allium. In our material, several sectionor species-specific character combinations (of shape and relative length of pollen grains as well as sulcus lengths and diameter of tectum perforations) occurred, but these results need verification by study of much more material. Underlining this statement, we found disagreeing with data from literature variation pattern of muri shape and perforation density for A. cristophii, A. regelii, A. giganteum, A. xiphopetalum, and A. scabriscapum.

Allium monophyllum (Amaryllidaceae) is a diploid species

In the last decade there was a remarkable progress in karyological analyses among members of Allium Linnaeus (1753: 294) subg. Melanocrommyum (Webb & Berthelot 1848: 347) Rouy (1910: 378) (Gurushidze et al. 2012, Genc et al. 2013, Akhavan et al. 2015, Genc & Firat 2016, Fritsch 2016), confirming that most species are diploid based on x = 8 (x = 9 and x = 10 are only rare exceptions, Fritsch & Astanova 1998). Triploid plants were rarely found in some members of A. sect. Melanocrommyum Webb & Berthel. (Tzanoudakis 1999, Genc & Ozhatay 2014). The tetraploid level was repeatedly reported by several authors for A. cyrilli Tenore (1827: 364) and sporadically for some other species, but higher ploidy levels were only exceptionally reported: 2n = 48 for A. cyrilli by Khoshoo et al. (1966) and for A. giganteum Regel (1883: 97) by Mensinkai (1939), and even 2n = 64 for A. monophyllum Vved. in Czerniakowska (1930: 266) by Kurita (1956). Unfortunately, these hexa- and octoploid counts were based on plants from botanical collections, and the taxonomic identity cannot be proofed because herbarium vouchers of these counts are not known to exist.