Interspecific gene flow and an intermediate molecular profile of Dyckia julianae (Bromeliaceae), an endemic species from southern Brazil

Abstract

When related species are distributed in sympatric populations, hybridization may occur. Likewise, one or more of these species may have arisen through historical hybridization between taxa. Here, we aim to elucidate the occurrence of hybridization among three Dyckia spp. (Bromeliaceae) from southern Brazil. We used seven nuclear and six plastid microsatellite loci to assess patterns of genetic diversity, population structure and hybridization in the three species. Furthermore, we performed manual crosses between species to test compatibility and fertility. The results showed that Dyckia julianae has an intermediate molecular profile, low gene flow occurs between Dyckia hebdingii and Dyckia choristaminea and higher gene flow occurs between D. julianae and the other two species. Plastid microsatellites identified 12 haplotypes that are shared among the species. The manual crosses between D. julianae and the other two species produced viable seeds, but no crosses between D. hebdingii and D. choristaminea generated fruits. Our data suggest that the reproductive barrier between D. julianae and the other two species is permeable. Further investigation into the hybrid origin hypothesis of D. julianae should be undertaken, as well as the mechanisms involved in reproductive isolation between D. hebdingii and D. choristaminea.

From micro- to macroevolution: insights from a Neotropical bromeliad with high population genetic structure adapted to rock outcrops

“…Bromeliads adapted to rock outcrops, such as the recently radiated Pitcairnia genus (11.8 Mya, Schütz et al 2016;Schubert 2017), are particularly suitable for addressing the potential role of intra-and interspecific gene flow during plant speciation and radiation, and establishing connections between macro-and microevolutionary processes (Palma- Silva et al , 2020Mota et al 2019). In fact, bromeliads are emerging as model systems for understanding evolutionary genetics and the ecology of species' complex of radiations in naturally fragmented habitats (Barbará et al 2007;Boisselier-Dubayle et al 2010;Lavor et al 2014;Palma-Silva et al 2011Lexer et al 2016;Hmeljevski et al 2017;Gonçalves-Oliveira et al 2017;Hirsch et al 2020;Pinange et al 2017;Ruas et al 2020;Wöhrmann et al 2020).…”

IAPT chromosome data 31

“…As mentioned above, Hirsch & al. (2019) showed that D. julianae has an intermediate molecular profile when compared to D. hebdingii and D. choristaminea (both with pure molecular profiles), raising questions about the origin of this pattern.…”

“…Dyckia choristaminea, D. hebdingii and D. julianae are endemic to southern Brazil with restricted distribution, often occurring in sympatry (Smith & Downs, 1974;Strehl, 2004). Hirsch & al. (2019), analyzing sympatric populations of these three species through SSR markers, found an intermediate molecular profile for D. julianae when compared to the other two species.…”

“…Cytogenetic data obtained for the three sympatric species of Dyckia are presented in Table 4 and discussed taking into account the recent study of our team (Hirsch & al., 2019) involving molecular markers and hybridization of these species.…”

Structural anomalies in pollen grains of Dyckia racinae L.B.Sm. (Bromeliaceae)

“…The description of pollen variants of D. racinae is an important record for studies of Bromeliaceae reproductive biology. We suggest that experimental analyzes of genetic and environmental factors are important for elucidation of the anomalies presented here, since most of them are related to stress during the reproductive process, or phenomena such as hybridization, both possible scenarios in the context of Dyckia, a genus with xerophytic species (Benzing 2000;Dorneles et al 2014) and quite susceptible to hybridization (Hirsch et al 2019). Furthermore, future ultrastructural and ontogenetic approaches should contribute to a better understanding of the reported anomalies at cellular level.…”