Karyotype Evolution and New Chromosomal Data in Erodium: Chromosome Alteration, Polyploidy, Dysploidy, and Symmetrical Karyotypes
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Turkish Journal of Botany Turk J Bot (2020) 44: 255-268 http://journals.tubitak.gov.tr/botany/ © TÜBİTAK Research Article doi:10.3906/bot-1912-22 Karyotype evolution and new chromosomal data in Erodium: chromosome alteration, polyploidy, dysploidy, and symmetrical karyotypes 1 2 3 1 4, Esra MARTİN , Ahmet KAHRAMAN , Tuncay DİRMENCİ , Havva BOZKURT , Halil Erhan EROĞLU * 1 Department of Biotechnology, Faculty of Science, Necmettin Erbakan University, Konya, Turkey 2 Department of Biology, Faculty of Arts and Science, Uşak University, Uşak, Turkey 3 Department of Biology Education, Necatibey Education Faculty, Balıkesir University, Balıkesir, Turkey 4 Department of Biology, Faculty of Science and Arts, Yozgat Bozok University, Yozgat, Turkey Received: 18.12.2019 Accepted/Published Online: 27.03.2020 Final Version: 06.05.2020 Abstract: Chromosomal data are valuable and very useful for revealing evolution and speciation processes. Due to its wide distribution throughout the world, morphological differences, and chromosomal alterations, Erodium L’ Hé r. is an important genus for investigating the relationship between chromosomal alterations and karyotype evolution. In the present study, the chromosome records of 15 taxa are provided; three are reported here for the first time (E. birandianum, E. gaillardotii, and E. hendrikii), seven present new chromosome numbers, and five are in agreement with previous reports. Karyotype evolution is summarized in the light of this data, and four different genomes are presented in the genus. Millions of years ago the ancestral karyotype was x = 9 in Asia (Genome I). Then, karyotypesx = 8 (Genome II) and x = 10 (Genome III) were shaped through dysploidy in Anatolia and Asia. They were distributed in the Mediterranean Basin through the Anatolian land bridge and in North and South America via the Bering land bridge and the North Atlantic land bridge. Finally, a high proportion of polyploidization was observed in secondary centers, especially the Mediterranean Basin and Australia (Genome IV). Key words: Anatolia, ancestral, Erodium, Geraniaceae, Mediterranean Basin 1. Introduction crossover barriers for speciation and diversification Chromosomal data support the characteristics determining (Baltisberger and Hörandl, 2016). Some genera of the family karyotype evolution and karyotypic relationships. The Geraniaceae are excellent systems to use for determining primary characteristics of karyotype are basic chromosome speciation and diversification. number (x), diploid chromosome number (2n), and Geraniaceae is a cosmopolitan family with five genera: chromosome length. These characteristics could be California Aldasoro & C.Navarro & P.Vargas & L.Sáez modified numerically through polyploidy and aneuploidy, & Aedo, Erodium L’Hér., Geranium L., Monsonia L., and as well as through structural rearrangements including Pelargonium L’Hér. The genus Erodium is distinguished translocations (which could modify the chromosome from the others by its five staminodes. AlthoughErodium number through dysploidy), deletions, and inversions. has fewer species than Geranium and Pelargonium, it has All of these events generate intraspecific and interspecific undergone important shifts in speciation (Fiz-Palacios variability of karyotypes, alter chromosome morphology, et al., 2010). Furthermore, members of the genus have mainly by changing the centromere position, and affect high diversity, as they can be annual or perennial; all karyotype asymmetry indexes as mean centromeric autogamous, mixed-mating, or (usually) allogamous; and asymmetry (MCA) and coefficient of variation of hermaphrodite or dioecious. Erodium is an important chromosome length (CVCL) (Schubert, 2007; Guerra, 2008; model for examining karyotype evolution due to the Schubert and Lysak, 2011; Guerra, 2012; Şirin et al., 2019). global distribution of species, different basic chromosome Mechanisms such as hybridization or polyploidization numbers, and various ploidy levels (Fiz et al., 2008). contribute significantly to changing chromosomal Anatolia is an important region for determining the behavior (Winterfeld et al., 2018). Karyotypic variations karyotype evolution and geographic distribution of and chromosomal differences produce sudden postzygotic- Erodium species. * Correspondence: [email protected] 255 This work is licensed under a Creative Commons Attribution 4.0 International License. MARTİN et al. / Turk J Bot Erodium contains 74 annual and perennial species greatest diversity, hosting 30 taxa including 16 endemics distributed on all continents except Antarctica. The (Oskay, 2017). Mediterranean Basin region is a major center of The chromosomal data are reported from 68 species. diversity of the genus and hosts 62 species, unlike other Forty-six species are only diploid; however, they reveal continents which have fewer native species (Figure 1): three different basic numbers: x = 8 (2n = 16), x = 9 five in Australia, four in Asia, and one each in North and (2n = 18), and x = 10 (2n = 20) (Fiz et al., 2006). Seven South America (Alarcón et al., 2003; Fiz et al., 2006; Fiz- species are polyploid and reveal three different polyploidy Palacios et al., 2010; Coşkunçelebi et al., 2012). In terms of levels: tetraploidy (2n = 4x = 36 and 40), hexaploidy (2n species diversity in Erodium, the Mediterranean Basin is = 6x = 60), and octoploidy (2n = 8x = 80) (Carolin, 1958; divided into two subregions: the western Mediterranean, Guittonneau, 1965a, 1966, 1967; Kentzinger, 1974; Diaz et with section Barbata (Boiss.) Guitt., and the Eastern al., 1992; Fiz et al., 2006). Erodium macrocalyx (G.López) Mediterranean, with subsection Absinthioidea (Brumh.) López Udias & Fabregat & Mateo shows a high ploidy Guitt. (Fiz-Palacios et al., 2010). Southwest Asia is one of level (2n = ca. 160) (Fiz et al., 2006). Fifteen species are the main centers of Erodium diversity, and Turkey has the diploid and polyploid (Fiz et al., 2006). In addition, several Figure 1. The general distribution map of the genus Erodium (single asterisk represents native species, and double asterisk represents species of ancestral region) with the Mediterranean Basin as a major center (including chromosome numbers reported from the Mediterranean Basin species in this study). For detailed references see Fiz et al. (2006). 256 MARTİN et al. / Turk J Bot species show dysploidy, which is an alteration in basic analysis to determine the interspecific relationships; and number, generally by fusion, without the significant loss (viii) compares and discusses the hypothetical ancestral or gain of genetic material (Rottgardt, 1956; Pajaron, 1982; karyotype and new data. Fiz et al., 2006). In genus Erodium, the chromosomal data are generally based on reports of chromosome number, 2. Materials and methods karyotype analysis, and karyotype formula. Based on 2.1. Plant material phylogenetic relationships and evolution, Fiz et al. (2006) Fifteen Erodium taxa were collected from their natural examined 68 Erodium (66 species and two subspecies) and habitats across Turkey (Table 1). Exsicates were deposited four outgroups in molecular investigations and chose 74 at the herbarium of the Department of Biological Sciences Erodium species and three genera from Geraniaceae for at Middle East Technical University (METU) in Ankara, morphological analyses. They reported that the genera and live plants were kept in the Plant Systematics and Erodium and California formed a monophyletic group, and Phylogenetics Research Laboratory at Uşak University. the 68 Erodium taxa were sister with California. Moreover, 2.2. Chromosome preparation the trnL analysis showed three clades in a polytomy, Chromosome spreads were prepared from roots pretreated whereas the combined morphological and trnL-F analysis with α-mono-bromonaphthalene at 4 °C for 16 h, fixed in displayed California as sister to the 68 Erodium taxa. fixative solution containing absolute alcohol:glacial acetic The results also indicated the three basic chromosome acid (3:1, v:v) for 24 h, and stored in ethanol (70%) at 4 °C numbers with two main lineages (clade I: x = 8, 9, 10 and until use. Then, the roots were hydrolyzed in 1 N HCl at clade II: x = 10), polyploidy, and rare dysploidy (Fiz et al., 60 °C for 12 min and stained in 2% aceto-orcein. Finally, 2006). Fiz-Palacios et al. (2010) examined 58 Erodium preparations were made by the squash method (Altay et taxa and two outgroups [California macrophylla (Hook. & al., 2017; Martin et al., 2019). Arn.) Aldasoro & C.Navarro & P.Vargas & L.Sáez & Aedo 2.3. Karyotype analysis and Geranium biuncinatum Kokwaro] by nrITS sequence Ten metaphase plates were analyzed with Software Image combined with existing plastid data for biogeography Analyses (Bs200ProP) loaded on a personal computer. and phylogenetic relationships. They pointed out that the The following parameters were calculated: long arm (LA), phylogenetic relationships were similar to previous plastid short arm (SA), total length (LA + SA), arm ratio (LA / reconstructions. Additionally, their biogeographical SA), centromeric index [(SA) / (LA + SA) × 100], total reconstructions pointed to Asia as the ancestral region haploid length (THL), relative length [(LA + SA) × 100 / of Erodium, where it appeared approximately 18 million THL], and mean haploid length. The karyotype formulas years ago. The basic chromosome number isx = 9 in were determined based on centromere position (Levan species of the ancestral region (Figure 1). Distribution to et al., 1964). The