Origin of triploid Arachis pintoi (Leguminosae) by autopolyploidy evidenced by FISH and meiotic behaviour

Lavia, Graciela Inés; Ortiz, Alejandra Marcela; Robledo, Germán; Fernández, Aveliano; Seijo, Guillermo

doi:10.1093/aob/mcr108

Cited by 46 publications

(28 citation statements)

References 37 publications

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“…In triploids, unbalanced and unreduced gametes, especially the formation of triploid eggs, can lead to tetraploid or hexaploid formation, so that the triploid works as a “bridge” (Tate et al, 2005). This way of forming polyploids was observed in the natural population of Centaurea stoebe (Mraz et al, 2012) and other species (Ramsey and Schemske, 1998; Levin, 2002; Lavia et al, 2011). In Lippia alba , it is also possible that the cytotype with 2 n = 45 (triploid) has been working as a bridge that contributes to the origination of other cytotypes.…”

Section: Discussionmentioning

confidence: 52%

Lippia alba(Verbenaceae): A new tropical autopolyploid complex?

Reis

Sousa

Vale

et al. 2014

American J of Botany

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• Premise of the study: Tropical regions have high species diversity, and polyploidization is a major mechanism of speciation in plants. However, few cases of natural polyploidy have been reported in tropical regions. Lippia alba, is a tropical, aromatic shrub with a wide distribution, extensive morphological plasticity, and several chemotypes. The species has long been recognized as a diploid with 2n = 30 chromosomes. Recently, two variations in chromosome number (2n = 60; 2n = 12-60) have been reported, suggesting the occurrence of polyploidy within the species.• Methods: Flow cytometry was used to investigate the genome size in 106 accessions from 14 Brazilian States. Conventional and molecular cytogenetic techniques and pollen viability analysis were employed to characterize each chromosome number observed.• Key results: The DNA 1C-value varied from 1.17 to 3.45 pg, showing a large variation in genome size. Five distinct chromosome numbers were observed (2n = 30, 38, 45, 60, 90); three are cytogenetically described here for the first time. The 5S rDNA signals varied proportionally according to each chromosome number, but 45S rDNA sites did not. High rates of meiotic irregularity were observed, mainly in cytotypes with higher chromosome numbers.• Conclusions: The data provide new support for the occurrence of a polyploid series in Lippia alba. We provide a hypothesis for how this complex may have arisen. Other cryptic polyploid complexes may remain undiscovered in tropical regions.

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Section: Discussionmentioning

confidence: 52%

Lippia alba(Verbenaceae): A new tropical autopolyploid complex?

Reis

Sousa

Vale

et al. 2014

American J of Botany

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“…However, the mechanisms that lead to the formation of restitution nuclei are diverse, and range from persistent chromatin bridges, as in Arachis (Lavia et al 2011) and Begonia (Dewitte et al 2010), to spindle failures, as in several species of both monocotyledonous and dicotyledonous plants (Bretagnolle and Thompson 1995). The meiotic analysis here conducted in L. nervosus evidenced the presence of remaining bridges, some of them until telophase II.…”

Section: Autopolyploidy In the Section Notolathyrusmentioning

confidence: 68%

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

et al. 2012

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Knowledge of the chromosome variation in wild populations is essential to understand the pathways and restrictions of karyotype evolution in plants. The aim of this study is to conduct an intraspecific analysis of the karyotypes by fluorochrome banding and ribosomal DNA (rDNA) loci detection by fluorescent in situ hybridization (FISH) and of the meiotic behaviour in natural populations of Lathyrus nervosus, sect. Notolathyrus. Chromosome banding showed that, despite the high constancy in the karyotype formula and in the rDNA loci among populations, there is intraspecific variation in the amount and distribution pattern of 4',6-diamidino-2-phenylindole (DAPI ? ) heterochromatin. However, those changes were not related to the total chromosome length of the haploid complements. This fact demonstrates that structural chromosome changes may be one of the most important mechanisms for karyotype variation among natural populations of L. nervosus. The chromosome number surveyed at the population level revealed the first case of polyploidy in South American species and the first case of uneven polyploidy of the genus. All the chromosome markers analysed indicated that the polyploids found originated by autopolyploidy. The meiotic analysis showed different chromosome abnormalities that may be generating numerical and structural changes in the sporads. The finding of unreduced gametes that are alive at anthesis suggests sexual polyploidization as the most probable mechanism involved in the origin of these 3x and 4x autopolyploid cytotypes in L. nervosus.

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“…On the other hand, since cytomixis is most frequently observed in microsporocytes, the cells that further form gametes, many researchers believe that this process may contribute to the changes in their ploidy level. The latter assumption is confirmed by numerous cases of diploid and polyploid pollen formation in the plants with a high rate of cytomixis in microsporogenesis (Falistocco et al, ; Ghaffari ; Lattoo et al, ; Song and Li ; Lavia et al, ; Alka et al, ). Unfortunately, any direct evidence for the effect of cytomixis on the ploidy of produced gametes is still lacking.…”

Section: Introductionmentioning

confidence: 83%

Distribution of telomeres in the tobacco meiotic nuclei during cytomixis

Mursalimov

Sidorchuk

Байбородин

et al. 2015

Cell Biology International

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Cytomixis is the migration of nuclei from one cell to another in higher plants, most frequently observable during microsporogenesis, which has a potential evolutionary significance. Currently, a major challenge is to label the chromatin migrating between cells to clarify its further fate. We have for the first time succeeded in visualizing the telomeric chromatin regions in the nuclei migrating between cells using fluorescent in situ hybridization. It has been shown that the telomeric signals in tobacco microsporocytes are randomly distributed in migrating nuclei without any deviations from their normal meiotic dynamics. According to our data, the chromatin migrating during cytomixis always contains telomeres and the telomeric signals are retained in the micronuclei formed after cytomixis.

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Origin of triploid Arachis pintoi (Leguminosae) by autopolyploidy evidenced by FISH and meiotic behaviour

Cited by 46 publications

References 37 publications

Lippia alba(Verbenaceae): A new tropical autopolyploid complex?

Lippia alba(Verbenaceae): A new tropical autopolyploid complex?

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

Distribution of telomeres in the tobacco meiotic nuclei during cytomixis

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