Dataset Information

Sexual intraspecific recombination but not de novo origin governs the genesis of new apomictic genotypes in Potentilla puberula (Rosaceae).

ABSTRACT: Apomixis - asexual reproduction via seeds - might arise de novo following polyploidisation events, or via reproductive transfer of apomixis. Both processes can be obtained within species or via hybridisation. We aimed to determine the origin of apomictic genotypes in Potentilla puberula, a rosaceous species showing reproductive differentiation with ploidy: sexual tetraploids and apomictic penta- to octoploids, which regularly co-occur in sympatry. The study is based on 726 individuals, comprising all cytotypes, collected from 138 populations in the Eastern European Alps. We established relationships of cytotypes based on AFLP fingerprinting and cpDNA sequencing to test (1) whether the apomicts are of recurrent allopolyploid origin or originated from within the species via autopolyploidy, and (2) whether there are indications for reproductive transfer versus de novo origin of apomixis. Three principal pathways were identified which explain the origin of new apomictic genotypes, all involving at least one apomictic parent and thus compatible with the idea of reproductive transfer of the apomictic trait to the progeny: (1) self-fertilisation of unreduced egg cells in apomicts; (2) cross-fertilisation among apomicts; and (3) occasionally, heteroploid crosses among sexuals and apomicts. Autopolyploids derived from tetraploid sexuals were repeatedly observed, but did not express apomixis. Finally, our results suggest no role of other species in the origin of extant apomictic genotypes of P. puberula, although local hybrids with P. crantzii were identified. In conclusion, our results show that the formation of new apomictic genotypes required a genetic contribution from at least one apomictic parent. This finding is in accordance with the idea that apomixis is inheritable in P. puberula. On the contrary, lack of apomixis in penta- and hexaploids derived from sexual backgrounds did not support the hypothesis of a de novo origin of apomixis. Relatively high frequency of remnant sexuality in the apomicts involving different cytological pathways of seed formation can explain their high cytological and genotypic diversity. Finally, lack of global introgression from a third taxon is in support of P. puberula as a concise, although highly diverse, species.

SUBMITTER: Nardi FD

PROVIDER: S-EPMC6382066 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Sexual intraspecific recombination but not de novo origin governs the genesis of new apomictic genotypes in Potentilla puberula (Rosaceae).

Nardi Flavia Domizia FD Dobeš Christoph C Müller Dorothee D Grasegger Tobias T Myllynen Tuuli T Alonso-Marcos Henar H Tribsch Andreas A

Taxon 20181201 6

Apomixis - asexual reproduction via seeds - might arise de novo following polyploidisation events, or via reproductive transfer of apomixis. Both processes can be obtained within species or via hybridisation. We aimed to determine the origin of apomictic genotypes in Potentilla puberula, a rosaceous species showing reproductive differentiation with ploidy: sexual tetraploids and apomictic penta- to octoploids, which regularly co-occur in sympatry. The study is based on 726 individu ...[more]

PMID: 30799883

Similar Datasets

Project description:Apomixis evolves from a sexual background and usually is linked to polyploidization. Pseudogamous gametophytic apomicts, which require a fertilization to initiate seed development, of various ploidy levels frequently co-occur with their lower-ploid sexual ancestors, but the stability of such mixed populations is affected by reproductive interferences mediated by cross-pollination. Thereby, reproductive success of crosses depends on the difference in ploidy levels of mating partners, that is, on tolerance of deviation from the balanced ratio of maternal versus paternal genomes. Quality of pollen can further affect reproductive success in intercytotype pollinations. Cross-fertilization, however, can be avoided by selfing which may be induced upon pollination with mixtures of self- and cross-pollen (i.e., mentor effects). We tested for reproductive compatibility of naturally co-occurring tetraploid sexuals and penta- to octoploid apomicts in the rosaceous species Potentilla puberula by means of controlled crosses. We estimated the role of selfing as a crossing barrier and effects of self- and cross-pollen quality as well as maternal: paternal genomic ratios in the endosperm on reproductive success. Cross-fertilization of sexuals by apomicts was not blocked by selfing, and seed set was reduced in hetero- compared to homoploid crosses. Thereby, seed set was negatively related to deviations from balanced parental genomic ratios in the endosperm. In contrast, seed set in the apomictic cytotypes was not reduced in hetero- compared to homoploid crosses. Thus, apomictic cytotypes either avoided intercytotype cross-fertilization through selfing, tolerated intercytotype cross-fertilizations without negative effects on reproductive success, or even benefitted from higher pollen quality in intercytotype pollinations. Our experiment provides evidence for asymmetric reproductive interference, in favor of the apomicts, with significantly reduced seed set of sexuals in cytologically mixed populations, whereas seed set in apomicts was not affected. Incompleteness of crossing barriers further indicated at least partial losses of a parental genomic endosperm balance requirement.

Dataset Information

Sexual intraspecific recombination but not de novo origin governs the genesis of new apomictic genotypes in Potentilla puberula (Rosaceae).

Publications

Sexual intraspecific recombination but not <i>de novo</i> origin governs the genesis of new apomictic genotypes in <i>Potentilla puberula</i> (Rosaceae).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets