Reproduction biology and chloroplast inheritance in Bromeliaceae: a case study in Fosterella (Pitcairnioideae)

Abstract

We applied a series of intra-and interspecific in situ cross-pollination experiments under greenhouse conditions to evaluate the breeding systems in four Fosterella species (Pitcairnioideae s.str.; Bromeliaceae). Viable hybrids were produced between each pair of the investigated species, suggesting that reproduction barriers may be low also under natural conditions. Seed germination rates proved to be high in each crossing treatment, indicating a high viability of the artificial hybrids. Large numbers of seeds were produced after both closed and open pollination treatments, suggesting that autogamy may be a major reproductive strategy in the genus. Our results support the concept that self-compatibility is an appropriate way to avoid natural hybridization in Bromeliaceae and could assist in maintaining species integrity in the presence of pollen flow. Paternity was verified in all crosses by genotyping parents and offspring with a set of polymorphic nuclear microsatellite markers. To study the mode of chloroplast inheritance, we developed a novel set of 24 chloroplast microsatellite markers using 454 pyrosequencing technology, and applied four of these markers for genotyping parents and offspring from all crosses. Our results clearly demonstrated a maternal inheritance of plastids.

The role of hybridization and introgression in maintaining species integrity and cohesion in naturally isolated inselberg bromeliad populations

“…; Wagner et al . ; Neri et al . , ) studies have recognised that selfing rather than outcrossing rates hamper hybridization and introgression, and thus represent an important pre‐zygotic reproductive isolation barrier.…”

“…; Wagner et al . ) and natural hybridization has been recorded in some species (Gardner ; Luther ; Wendt et al . , ; Gonçalves & de Azevêdo‐Gonçalves ; Schulte et al .…”

Hybridization between two sister species of Bromeliaceae:Vriesea carinataandV. incurvata

“…In addition, the presence of plastid DNA haplotypes of both parental species in the hybrids (Fig. 4) suggests that hybridization is bidirectional between these two species, considering that the plastid genome in Bromeliaceae is maternally inherited (Wagner et al, 2015). Palma-Silva et al (2011) also observed that hybridization between Pitcairnia albiflos Herb.…”

Microsatellites from Fosterella christophii (Bromeliaceae) by de novo transcriptome sequencing on the Pacific Biosciences RS platform

“…Observed and expected heterozygosity values ranged from zero to 1 and from 0.17 to 0.83, respectively. Significant deviations from HWE in terms of heterozygote deficiency were detected at three loci (Foc_01, Foc_05, Foc_12) in population NW09.005 and at one locus (Foc_18) in population NW09.034, which is possibly explained by the potential of Fosterella species to self-pollinate (Wagner et al, 2015). With one exception (Foc_04), all 13 loci were also polymorphic in F. micrantha (two to 11 alleles) and in F. villosula (two to six alleles) (Table 2).…”

“…Such high levels of similarity are surprising, given that F. micrantha is endemic to Central America, whereas the other two species reside in the Bolivian Andes. Controlled pollination experiments indicated that all three species are self-compatible but also form viable hybrids (Wagner et al, 2015). To investigate the genetic diversity and differentiation in this closely related species complex, we used Pacific Biosciences’ single-molecule real-time (SMRT) technology (Eid et al, 2009) to develop a set of genic microsatellite markers in F. christophii .…”