Margret Veltman

• Anthoons, Bastien; Veltman, Margret; Tsiftsis, Spyros; Gravendeel, Barbara; Drouzas, Andreas D. & Boer, Hugo de [Show all 7 contributors for this article] (2025). Exploring the potential of Angiosperms353 markers for species identification of Eastern Mediterranean orchids. Molecular Phylogenetics and Evolution. ISSN 1055-7903. 209. doi: 10.1016/j.ympev.2025.108360. Full text in Research Archive Show summary

  Tuberous orchids are ecologically vulnerable species, threatened by a range of environmental pressures such as overharvesting, grazing and land use change. Conservation efforts require accurate species identification, but are impeded by limited phylogenetic resolution of traditional genetic markers, which is exacerbated by widespread taxonomic conflict regarding the classification of orchids. Target enrichment holds promise to resolve both these challenges by offering a large set of nuclear loci with which to increase phylogenetic resolution and evaluate competing species models. Here, we evaluate the effectiveness of the Angiosperms353 markers for distinguishing over 50 tuberous orchid species native to Greece and we explore the possibility of narrowing these markers to a smaller set that could function as a minimal probe set. Our methodology consists of a three-tiered approach: 1) generating a species-level phylogeny using all Angiosperms353 loci with sufficient target recovery, 2) evaluating competing species models based on “splitter” and “lumper” classifications through Bayes Factor species delimitation, and 3) ranking the potential of Angiosperms353 loci to discriminate representatives of lineages with different divergence times based on their phylogenetic informativeness. While the inferred multi-species coalescent phylogeny had overall high support, Bayes Factor delimitation revealed mixed outcomes, favouring splitting in Serapias, while favouring splitting in basal clades and lumping in more recently diverged clades in Ophrys. A molecular clock analysis of Ophrys confirms rapid and recent radiation in clades marked by phylogenetic uncertainty, suggesting the need for additional loci to fully resolve this genus. Finally, we found 30 loci to be highly phylogenetically informative across four epochs of Orchidinae evolution; we suggest these are promising candidates for future marker development. Our findings enhance the Plant Tree of Life (PAFTOL) by contributing additional phylogenomic data for species that were previously underrepresented in trees built with these markers, while shedding light on the ongoing “splitter”-vs-“lumper” debate and offering new directions for species identification of tuberous orchids, a group with distinct taxonomic and conservation challenges.

• Scharwies, Johannes D.; Clarke, Taylor; Zheng, Zihao; Dinneny, Andrea; Birkeland, Siri & Veltman, Margret [Show all 16 contributors for this article] (2025). Moisture-responsive root-branching pathways identified in diverse maize breeding germplasm. Science. ISSN 0036-8075. 387(6734), p. 666–673. doi: 10.1126/science.ads5999. Full text in Research Archive
• Veltman, Margret; Anthoons, Bastien; Schrøder-Nielsen, Audun; Gravendeel, Barbara & Boer, Hugo de (2024). Orchidinae-205: A new genome-wide custom bait set for studying the evolution, systematics, and trade of terrestrial orchids. Molecular Ecology Resources. ISSN 1755-098X. doi: 10.1111/1755-0998.13986. Full text in Research Archive Show summary

  Terrestrial orchids are a group of genetically understudied, yet culturally and economically important plants. The Orchidinae tribe contains many species that produce edible tubers that are used for the production of traditional delicacies collectively called ‘salep’. Overexploitation of wild orchids in the Eastern Mediterranean and Western Asia threatens to drive many of these species to extinction, but cost-effective tools for monitoring their trade are currently lacking. Here we present a custom bait kit for target enrichment and sequencing of 205 novel genetic markers that are tailored to phylogenomic applications in Orchidinae s.l. A subset of 31 markers capture genes putatively involved in the production of glucomannan, a water-soluble polysaccharide that gives salep its distinctive properties. We tested the kit on 73 taxa native to the area, demonstrating universally high locus recovery irrespective of species identity, that exceeds the total sequence length obtained with alternative kits currently available. Phylogenetic inference with concatenation and coalescent approaches was robust and showed high levels of support for most clades, including some which were previously unresolved. Resolution for hybridizing and recently radiated lineages remains difficult, but could be further improved by analysing multiple haplotypes and the non-exonic sequences captured by our kit, with the promise to shed new light on the evolution of enigmatic taxa with a complex speciation history. Offering a step-up from traditional barcoding and universal markers, the genome-wide custom loci targeted by Orchidinae-205 are a valuable new resource to study the evolution, systematics and trade of terrestrial orchids.

• Veltman, Margret; Flowers, Jonathan M; Andel, Tinde R. van & Schranz, M Eric (2019). Origins and geographic diversification of African rice (Oryza glaberrima). PLOS ONE. 14(3). doi: 10.1371/journal.pone.0203508. Full text in Research Archive
• Andel, Tinde R. van; Veltman, Margret; Bertin, Alice; Maat, Harro; Polime, Thomas & Lambers, Derk Hille Ris [Show all 9 contributors for this article] (2019). Hidden Rice Diversity in the Guianas. Frontiers in Plant Science. doi: 10.1101/562769. Full text in Research Archive Show summary

  Traditional crop varieties are an important source of genetic diversity for crop adaptation and modern breeding. Landraces of Asian (Oryza sativa) and African (Oryza glaberrima) rice have been well studied on the continents where they were domesticated. However, their history of cultivation in northern South America is poorly understood. Here, we reveal the rice diversity that is maintained by Maroons, descendants of enslaved Africans who fled to the interior forests of the Guianas ca. 300 years ago. We interviewed subsistence farmers who practice shifting cultivation along the Maroni and Lawa rivers that form the natural border between French Guiana and Suriname, and used ethnobotanical and morphological methods to identify around 50 varieties, of which 15 were previously undocumented. The genetic origin of these varieties was explored using the Angiosperms353 universal probe set. Despite the large distances between sites and relative inaccessibility of the area, phenotypic and genetic diversity did not display any geographic structure, which is consistent with knowledge of seed exchange among members of the same ethnolinguistic group. Although improved US cultivars were introduced in Maroon villages in the 1940s, these have not displaced the traditional landraces, which are cherished for their taste and nutritious qualities and for their importance in Maroon spiritual life. The unique agricultural and ritual practices of Maroons confirm their role as custodians of rice diversity, a role that is currently under threat from external pressures and encroaching globalization. We expect that the rice diversity uncovered in this study represents only a fraction of the total diversity in the Guianas and may constitute a large untapped resource that holds promise for future rice improvement. Further efforts to inventory and preserve these landraces will help to protect a precious cultural heritage and local food security.

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