Sexual, apomictic and mixed populations in Handroanthus ochraceus (Bignoniaceae) polyploid complex

Mendes, Mariana Gonçalves; Oliveira, Ana Paula de Lima; Oliveira, Paulo Eugênio; Bonetti, Ana Maria; Sampaio, Diana Salles

doi:10.1007/s00606-018-1512-5

Cited by 11 publications

(4 citation statements)

References 36 publications

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“…Changes in ploidy have occurred commonly in the group (Costa et al 2017;Mendes-Rodrigues et al 2019). Mixed ploidy populations have been documented for Handroantus ochraceous (Bignoniaceae), another agamic polyploid complex in Cerrado (Mendes et al 2018). However, for the Eriotheca studied here, we did not find evidence of further admixture or mixed populations.…”

Section: Stomata and Genome Size Measurementscontrasting

confidence: 64%

Interploidy hybridization in Eriotheca gracilipes and E. pubescens (Malvaceae): experimental evidence, genome and stomatal size

et al. 2022

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Hybridization and changes in ploidy have been associated with shifts from sexuality to apomixis, and may explain isolation among populations and species. Hybrids resulting from interploidy crosses may contribute to a broader understanding of how these populations and species have originated and evolved. Stomatal morphometrics and flow cytometry analyses were carried out for seedlings from different populations of Eriotheca estevesiae, E. gracilipes and E. pubescens, a group of closely related tree species in the Central Brazilian Cerrados. Controlled cross-pollinations between individuals of different cytotypes of E. gracilipes (2n = 2x = 92 and 2n = 6x = 276) and between sexual cytotypes of E. gracilipes (2n = 2x = 92) and E. pubescens (2n = 4x = 184) were performed. Only one viable seed was obtained from interploidy crosses of E. gracilipes. The hybridization between sexual cytotypes did not produce fruits. Genome size analyses indicated that there were apparently no natural hybrids or mixed ploidy populations among the seedlings analyzed. Seedlings stomatal size was consistent with previously reported cytotypes and ploidy levels; and when compared with the stomata of the viable interploidy hybrid of E. gracilipes, indicated a tetraploid, intermediate ploidy level. Although the data suggest the possibility of interploidy hybridization, cytotypes appeared relatively stable and natural interploidy hybridization seems to be uncommon among Eriotheca trees.

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Section: Stomata and Genome Size Measurementscontrasting

confidence: 64%

Interploidy hybridization in Eriotheca gracilipes and E. pubescens (Malvaceae): experimental evidence, genome and stomatal size

et al. 2022

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“…An insertion at the promotor region of CitRWP is associated with polyembryony (Wang et al, 2017). Similar as in gametophytic apomixis, adventitious embryony often appears in polyploids and/or hybrids (Alves et al, 2016; Mendes et al, 2018), but also in diploids or paleopolyploids (Carman, 1997; Whitton et al, 2008).…”

Section: The Foundational Phase: the Emergence Of An Apomictic Indivimentioning

confidence: 95%

The Rise of Apomixis in Natural Plant Populations

2019

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Apomixis, the asexual reproduction via seed, has many potential applications for plant breeding by maintaining desirable genotypes over generations. Since most major crops do not express natural apomixis, it is useful to understand the origin and maintenance of apomixis in natural plant systems. Here, we review the state of knowledge on origin, establishment and maintenance of natural apomixis. Many studies suggest that hybridization, either on diploid or polyploid cytotypes, is a major trigger for the formation of unreduced female gametophytes, which represents the first step toward apomixis, and must be combined to parthenogenesis, the development of an unfertilized egg cell. Nevertheless, fertilization of endosperm is still needed for most apomictic plants. Coupling of these three steps appears to be a major constraint for shifts to natural apomixis. Adventitious embryony is another developmental pathway toward apomixis. Establishment of a newly arisen apomictic lineage is often fostered by side-effects of polyploidy. Polyploidy creates an immediate reproductive barrier against the diploid parental and progenitor populations; it can cause a breakdown of genetic self-incompatibility (SI) systems which is needed to establish self-fertility of pseudogamous apomictic lineages; and finally, polyploidy could indirectly help to establish an apomictic cytotype in a novel ecological niche by increasing adaptive potentials of the plants. This step may be followed by a phase of diversification and range expansion, mostly described as geographical parthenogenesis. The utilization of apomixis in crops must consider the potential risks of pollen transfer and introgression into sexual crop fields, which might be overcome by using pollen-sterile or cleistogamous variants. Another risk is the escape into natural vegetation and potential invasiveness of apomictic plants which needs careful management and consideration of ecological conditions.

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“…Each assembly may be further improved by the incorporation of long-reads for gap-filling ( English et al 2012 ; Rhie et al 2020 ), linkage maps created by population resequencing ( The Heliconius Genome Consortium 2012 ; Kawakami et al 2017 ), or syntenic information from alignments of multiple draft Bignoniaceae genomes ( Kolmogorov et al 2018 ). Chromosome-scale assemblies of additional Bignoniaceae will aid further investigations of the remarkable variation in genome size and chromosome number documented in these taxa ( Collevatti and Dornelas 2016 ; Mendes et al 2018 ). Furthermore, phylogenomic investigations of Handroanthus and relatives in the Tabebuia alliance will increase resolution of unclear speciation histories ( Grose and Olmstead 2007a , 2007b ) that may involve hybridization among sympatric species ( Gentry 1992 ; Pinheiro et al 2018 ).…”

Section: Resultsmentioning

confidence: 99%

Genome assemblies for two Neotropical trees: Jacaranda copaia and Handroanthus guayacan

Burley

Kellner

Hubbell

et al. 2021

G3 Genes|Genomes|Genetics

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The lack of genomic resources for tropical canopy trees is impeding several research avenues in tropical forest biology. We present genome assemblies for two Neotropical hardwood species, Jacaranda copaia and Handroanthus (formerly Tabebuia) guayacan, that are model systems for research on tropical tree demography and flowering phenology. For each species, we combined Illumina short-read data with in vitro proximity-ligation (Chicago) libraries to generate an assembly. For J. copaia, we obtained 104X physical coverage and produced an assembly with N50/N90 scaffold lengths of 1.020 Mbp/0.277 Mbp. For H. guayacan, we obtained 129X coverage and produced an assembly with N50/N90 scaffold lengths of 0.795 Mbp/0.165 Mbp. J. copaia and H. guayacan assemblies contained 95.8% and 87.9% of benchmarking orthologs, although they constituted only 77.1% and 66.7% of the estimated genome sizes of 799 Mbp and 512 Mbp, respectively. These differences were potentially due to high repetitive sequence content (> 59.31% and 45.59%) and high heterozygosity (0.5% and 0.8%) in each species. Finally, we compared each new assembly to a previously sequenced genome for H. impetiginosus using whole-genome alignment. This analysis indicated extensive gene duplication in H. impetiginosus since its divergence from H. guayacan.

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Sexual, apomictic and mixed populations in Handroanthus ochraceus (Bignoniaceae) polyploid complex

Cited by 11 publications

References 36 publications

Interploidy hybridization in Eriotheca gracilipes and E. pubescens (Malvaceae): experimental evidence, genome and stomatal size

Interploidy hybridization in Eriotheca gracilipes and E. pubescens (Malvaceae): experimental evidence, genome and stomatal size

The Rise of Apomixis in Natural Plant Populations

Genome assemblies for two Neotropical trees: Jacaranda copaia and Handroanthus guayacan

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