A Synopsis of the Genus Stipa (Poaceae) in Middle Asia, Including a Key to Species Identification, an Annotated Checklist, and Phytogeographic Analyses

Gudkova

et al. 2020

Sci Rep

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Hybridisation in the wild between closely related species is a common mechanism of speciation in the plant kingdom and, in particular, in the grass family. Here we explore the potential for natural hybridisation in Stipa (one of the largest genera in poaceae) between genetically distant species at their distribution edges in Mountains of Central Asia using integrative taxonomy. Our research highlights the applicability of classical morphological and genome reduction approaches in studies on wild plant species. The obtained results revealed a new nothospecies, Stipa × lazkovii, which exhibits intermediate characters to S. krylovii and S. bungeana. A high-density DArTseq assay disclosed that S. × lazkovii is an F1 hybrid, and established that the plastid and mitochondrial DNA was inherited from S. bungeana. In addition, molecular markers detected a hybridisation event between morphologically and genetically distant species S. bungeana and probably S. glareosa. Moreover, our findings demonstrated an uncertainty on the taxonomic status of S. bungeana that currently belongs to the section Leiostipa, but it is genetically closer to S. breviflora from the section Barbatae. Finally, we noticed a discrepancy between the current molecular data with the previous findings on S. capillata and S. sareptana. Hybridisation in the wild between closely related species is a common mechanism of speciation in the plant kingdom 1-7. Due to the prevalence of polyploidy found in angiosperms it has been estimated that around 11% of flowering plants may have arisen through hybridisation events 4. In addition, speciation via hybridisation can lead to an equal ploidy number within parental and newly formed species 3. In general, hybridisation is often accompanied by introgression and causes gene transfer between species via repeated backcrossing 4,8-11. On the one hand it may have contributed to species diversity and speciation 5,12,13 , on the other, deleterious consequences of hybridisation such as decreased fitness, genetic assimilation and gene swamping may drive populations toward the brink of extinction 14-16. In the grass family (Poaceae) hybridisation and introgression are well studied mainly for economically impor

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphological and genome-wide evidence for natural hybridisation within the genus Stipa (Poaceae)

Baiakhmetov

Gudkova

et al. 2020

Sci Rep

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“…According to the ten-volume study of the flora of the former Soviet Tajik Republic [11][12][13][14][15][16][17][18][19][20] supplemented by the works of Zakirov 21 , Tzvelev 22 , Ikonnikov 23 and more recently by, for example, Nobis et al 24,25 and Nowak & Nobis 26 , the vascular flora of the Pamir-Alai consists of ca. 4,300 species assigned to 116 families.…”

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confidence: 99%

Red List of vascular plants of Tajikistan – the core area of the Mountains of Central Asia global biodiversity hotspot

Świerszcz

et al. 2020

Sci Rep

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Central Pamir-Alai, which is located almost entirely within the area of Tajikistan, is one of the world hotspots of biodiversity, harbouring ca. 4,300 species and 1,400 endemic plants. The first application of the IUCN Red List criteria reveals that among all native species occurring in Tajikistan 1,627 taxa (38.11%) are threatened, including 23 extinct (0.54%), 271 (6.34%) critically endangered (CR), 717 (16.79%) endangered (EN) and 639 (14.96%) vulnerable (VU). Globally, 20 taxa are extinct, 711 (16.65%) threatened, including 144 (3.37%) critically endangered, 322 (7.54%) endangered and 245 (5.73%) vulnerable. As we found positive correlation between human density and the number of threatened species, we suspect this indirect factor responsible for the species diversity decline. Extinct or threatened taxa have short blooming periods in spring or early summer, have limited geographical range and inhabit mainly valley bottoms at lower altitudes. Threatened taxa occupy extremely dry or wet habitats, such as deserts, semi-deserts, water reservoirs and fens. The group of threatened plants consists mostly of Central Asian, Indo-Indochinese and Arctic species. Ornamental plants have a higher extinction risk than other plants, but species collected for medicinal reasons and used for forage or food reveal lower retreatment rate. Our assessment fills a gap for important plant area and provides the data for raising the effectiveness of plant diversity conservation. Species diversity loss still remains one of the main imperatives of our time and therefore one of the main topics of scientific studies. Currently, hundreds of plant species and many habitat types are globally threatened 1,2. A range of factors are responsible for these declines, with human population growth, habitat fragmentation and climate change regarded as the most crucial 3. The continuing decline of plant diversity demands continuous research on evaluation of the conservation status of flora with the use of comprehensive International Union for Conservation of Nature (IUCN) criteria (www.iucnredlist.org). These criteria are widely recognised as the most comprehensive tool for assessing the global conservation status of species and categorising plants according to their estimated risk of extinction (e.g. Orsenigo et al. 4 , Maes et al. 5). As the most effective conservation actions, policies and law implementation take place at the national scale, numerous countries have established national lists of threatened species with the use of IUCN criteria and guidelines at regional levels (Rossi et al. 6). Despite some biases and shortcomings of scientific foundations 7 , red lists are widely accepted as an appropriate measure for setting conservation priorities. In some countries, including Tajikistan, they also have a legal status and directly influence the state governance of the plant diversity 8. However, based on the information available in the National Red List Database 9 , almost 20% of Eurasian countries still have no available red lists for vascular p...

Proceedings of the VII International Scientific Conference, Dedicated to the 135th Anniversary of the P.N. Krylov Herbarium of

“…The BOP species are known as the "cool season" or "pooid" grasses and all are C3 and distributed in temperate climates. Following Tzvelev (1974), the genus Stipa includes six main sections Barbatae Junge, Leiostipa Dumort, Pseudoptilagrostis Tzvelev, Regelia Tzvelev, Stipa, and Smirnovia Tzvelev, and comprises over 150 species native to Asia, Europe and North Africa (Nobis, 2014;Nobis et al, 2020). In its strict sense, the genus is monophyletic, but subdivisions within the genus are not consistently supported by available molecular data (Kellogg, 2015).…”

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confidence: 99%

“…Based on morphology, a hybrid origin can be attributed to ca. 30 % of Stipa species, where only in Middle Asia 23 of 72 species are regarded as nothospecies (Nobis et al, 2020).…”

mentioning

confidence: 99%

Applying integrative taxonomy as a tool for revealing hybridisation events in Stipa (Poaceae)

Baiakhmetov¹,

Gudkova²,

Nobis³

2020

Hybridisation in the wild between closely related species is a common mechanism of speciation in the plant kingdom and, in particular, in the grass family. Here we show the usefulness of integrative taxonomy as a tool for revealing hybridisation events in Stipa (one of the largest genera in Poaceae). We demonstrate the usage of the classical morphological approach combining with scanning electron microscopy data, as well as analyses of pollen grains, and the application of molecular techniques including data derived from next generation sequencing. We illustrate the application of this integrative tool by specific examples: (1) in the S. × heptapotamica hybrid complex comprising morphologically distant but genetically closely related species, and (2) in the S. × lazkovii hybrid complex containing genetically distant species.