Cytogenetic and molecular characterization of morphologically variable Sisyrinchium micranthum (Iridaceae) in southern Brazil

Abstract

Sisyrinchium micranthum is native to southern Brazil and shows a wide range of morphological variation in this region. This study was performed to compare individuals of this species in terms of traits such as morphology, chromosome number, meiotic behaviour, pollen viability and genetic diversity using inter simple sequence repeat markers. First, general morphological aspects were evaluated and plants were classified into three morphological categories (CI, CII and CIII) to analyse the cytogenetic and genetic data. Three chromosome numbers corresponding to three ploidies were found: 2n = 2x = 16, 2n = 4x = 32 and 2n = 6x = 48. All morphological types showed regular meiotic behaviour and high meiotic index values and pollen viability. CII is the most frequent in southern Brazil. The most common haploid chromosome number, n = 8, has not been reported previously in this species. The percentage of polymorphic loci ranged from 6.45 to 61.29% for each accession. Molecular and cytogenetic analyses indicate that some S. micranthum accessions may have more than one ploidy. This study represents the first effort to characterize this taxonomically complex species based on cytogenetic and genetic aspects.

Differentiation between two self-compatible cytotypes of Herbertia lahue (Iridaceae): evidence from genotypic and phenotypic variation

“…This approach was effective for detecting some variations between cytotypes of Sisyrinchium micranthum Cav. (Tacuatiá et al 2012b) and among closely related taxa of Iris L. (section Oncocyclus), supporting some taxonomic decisions in this species complex (Arafeh et al 2002;Saad and Mahy 2009).…”

“…It is unclear whether other floral characters are suitable for distinguishing hexaploids and octoploids of H. lahue. Often, morphological studies on species that share cytotypic variation have led to the discovery of subtle differences between cytotypes, typically in terms of floral characteristics (Keeler and Davis 1999;Guldahl et al 2005;Tacuatiá et al 2012b;Kellner et al 2014). Cytotypes from H. lahue can possibly be discriminated by combining analysis of morphological and molecular characters.…”

O Estudo Da Biodiversidade E Evolução Vegetal Através De Marcadores De Dna E Citogenética: Exemplos Em Iridaceae E Poaceae

“…Uma característica importante para a família é a extensa variação morfológica vista em alguns grupos, o que torna os relacionamentos internos complexos. Assim, marcadores moleculares têm sido utilizados com sucesso tanto para a caracterização molecular de cultivares e de espécies (CAIOLA, CAPUTO & ZANIER, 2004;DE MARCO et al, 2009;MORAGA et al, 2010;RANJAN et al, 2010;TACUATIÁ et al, 2012b), quanto para a obtenção de estimativas de parâmetros de genética de populações (HANNAN & ORICK, 2000;WRÓBLEWSKA et al, 2003;DE MARCO et al, 2009;TACUATIÁ et al, 2012a), ou mesmo, para auxiliar na investigação de mecanismos envolvidos na especiação, correlacionando com informações ecológicas (RYMER et al, 2010). O mérito desses estudos foi esclarecer a complexidade evolutiva de alguns grupos de Iridaceae, evidenciando que a citogenética e a biologia da polinização foram fundamentais para a diversificação e para a adaptação de novidades evolutivas surgidas na família.…”

“…Das 14 espécies de Sisyrinchium cujos números cromossômicos foram obtidos pelo nosso grupo de pesquisa, Sisyrinchium micranthum Cav. (Figura 2-C) é um exemplo onde foram observados citótipos intraespecíficos, contemplando três diferentes níveis de ploidia (TACUATIÁ et al, 2012b). Também para Herbertia já foi encontrado mais de um nível de ploidia (2x, 4x, 6x e 8x) (WINGE, 1959;GOLDBLATT & TAKEI, 1997;ROITMAN & CASTILLO, 2004;MORENO et al, 2009).…”

Flora of Guaramacal (Venezuela): Monocotyledons

“…In Venezuela, found in the Andes (Mérida, Táchira, and Trujillo) and in the Cordillera de la Costa (Aragua, Distrito Federal, and Miranda; Map 99). In the park, found in open and rocky areas at the edge of forest on both slopes of Guaramacal; (1,700-)2,000-2,500 m. This is a morphologically and cytologically complex species (Tacuatiá et al, 2012) with an extensive range and a tendency to be invasive. Perennial herbs, (15-)22-32 cm tall; roots mostly fibrous, some thickened and tuberous, but always thin.…”