Breeding system variation, genetics and evolution in the Turneraceae

Shore, Joel S.; Arbo, María Mercedes; Fernández, Aveliano

doi:10.1111/j.1469-8137.2006.01807.x

Cited by 44 publications

(42 citation statements)

References 86 publications

(134 reference statements)

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“…Under the Primula S supergene model, the genotype of the short-styled morph at the S-locus is GPA/gpa whereas long-styled plants are gpa/gpa, where G/g determines style length and its incompatibility, P/p determines pollen size and its incompatibility and A/a determines stamen length (Dowrick, 1956;Lewis and Jones, 1992;Barrett and Shore, 2008). In Turnera, genetic studies are consistent with the hypothesis that a supergene comprised of at least two genes, determines distyly (Shore and Barrett, 1985;Tamari et al, 2005;Shore et al, 2006). In this study, 10 of the X-ray generated floral mutants had the long-styled phenotype indicating that all the S components of the putative supergene have been deleted.…”

Section: Discussionsupporting

confidence: 50%

Characterization of X-ray-generated floral mutants carrying deletions at the S-locus of distylous Turnera subulata

2010

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To investigate the genetic architecture of distyly in Turnera subulata and test the hypothesis that a supergene determines distyly, we used X-ray mutagenesis to generate floral mutants. Based upon the crossing design, all progeny were expected to be short-styled. Of 3982 progeny screened, 10 long-styled mutants, one long homostyle and one short homostyle were recovered. Assays for molecular markers tightly linked to the S-locus showed that the mutants were missing 1-3 markers indicating they are deletion mutants. We investigated the incompatibility phenotype of the mutants and found that both their styles and pollen behaved like those of the long-styled morph. There was a variation in the absolute length of styles, stamens and pollen size of the long-styled mutants. Furthermore, long-styled mutants possessing larger deletions tended to have their anthers and stigmas in closer proximity. We explored the inheritance of the S-locus mutations and found that only one of the deletion mutations was transmitted to progeny where we recovered seven such progeny. Remarkably, our data are consistent with the supergene model (GPA/gpa) of Primula. The long homostyle mutant appears to have deletions involving both the G and P loci. The other mutants appear to have deletions of the entire S-locus. The mutants generated will serve as a valuable resource for the molecular dissection of the S-locus region, and in the identification of genes determining distyly.

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Section: Discussionsupporting

confidence: 50%

Characterization of X-ray-generated floral mutants carrying deletions at the S-locus of distylous Turnera subulata

2010

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“…Similarly, distyly is also preserved in P. clusiana, the only other dodecaploid taxon of P. section Auricula . The high herkogamy and the conservation of heterostyly in Pm12x individuals corroborates the idea that polyploidization itself does not necessarily trigger the switch from heterostyly to homostyly (Shore et al, 2006;Naiki, 2012). Furthermore, the lack of transition to selfing is in line with the increase of petal lobe length in Pm12x individuals, suggesting that flower size in polyploids may be related to the importance of pollinators for plant reproduction (Vamosi et al, 2007).…”

Section: Discussionsupporting

confidence: 63%

Do floral and niche shifts favour the establishment and persistence of newly arisen polyploids? A case study in an Alpine primrose

Casazza

Boucher

Minuto

et al. 2016

Ann Bot

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Background and Aims Polyploidization plays a key role in plant evolution. Despite the generally accepted 'minority-cytotype exclusion' theory, the specific mechanisms leading to successful establishment and persistence of new polyploids remain controversial. The majority of newly formed polyploids do not become established, because they are less common, have fewer potential mates or may not be able to compete successfully with co-occurring progenitors at lower ploidy levels. Changes in floral traits and ecological niches have been proposed as important mechanisms to overcome this initial frequency-dependent disadvantage. The aim of this study was to determine whether dodecaploids of the heterostylous P. marginata differ from their hexaploid progenitors in P. marginata and P. allionii for selected floral traits and ecological preferences that might be involved in establishment and persistence, providing a possible explanation for the origin of polyploidized populations.Methods Floral morphological traits and ecological niche preferences among dodecaploids and their hexaploid progenitors in P. marginata and P. allionii, all restricted to the south-western Alps, were quantified and compared Key Results Differences in floral traits were detected between dodecaploids and their closest relatives, but such differences might be too weak to counter the strength of minority cytotype disadvantage and are unlikely to enable the coexistence of different cytotypes. Furthermore, the results suggest the preservation of full distyly and no transition to selfing in dodecaploids. Finally, dodecaploids occur almost exclusively in environments that are predicted to be suitable also for their closest hexaploid relatives.Conclusions In light of the results, P. marginata dodecaploids have probably been able to establish and persist by occupying geographical areas not yet filled by their closest relatives without significant evolution in their climatic and pollination niches. Dispersal limitation and minority-cytotype exclusion probably maintain their current range disjunct from those of its close relatives.

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“…However, chromosome numbers are unknown for the African genera. The genus Turnera including 66 % of the species of the family has three base chromosome numbers: x = 7, x = 5 and x = 13 (Fernández 1987), and polyploidy has played an important role in speciation, given that several species, including T. ulmifolia L. (type of the genus) are allopolyploids (Shore et al 2006). At present, Turnera is divided into 11 series, but critical information to change taxonomic circumscriptions is still missing, since the base number of ser.…”

Section: Genera From Continentalmentioning

confidence: 99%

Phylogenetic relationships within Turneraceae based on morphological characters with emphasis on seed micromorphology

2015

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Genera of Turneraceae differ notably in connation/adnation of calyx, corolla, and androecium. Floral and seed morphology were analyzed in all genera. Phylogenetic analyses were made using a matrix of 91 characters coded for 102 taxa including all genera of Turneraceae and all series of Turnera. Our goals were: assessing the impact of morphology in the cladistic analyses of Turneraceae and comparing our results with those based on molecular datasets. Our analyses suggest that all genera are monophyletic. The inclusion of seed micromorphology in the analyses increased resolution within Turnera, the strict consensus tree shows four main clades, each gathering two or more current series.

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Breeding system variation, genetics and evolution in the Turneraceae

Cited by 44 publications

References 86 publications

Characterization of X-ray-generated floral mutants carrying deletions at the S-locus of distylous Turnera subulata

Characterization of X-ray-generated floral mutants carrying deletions at the S-locus of distylous Turnera subulata

Do floral and niche shifts favour the establishment and persistence of newly arisen polyploids? A case study in an Alpine primrose

Phylogenetic relationships within Turneraceae based on morphological characters with emphasis on seed micromorphology

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