Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5–7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.
1 October 2021 in Molecular Phylogenetics and Evolution
Premise of the Study: While brinjal eggplant (Solanum melongena L.) is the second most important solanaceous fruit crop, we lack firm knowledge of its evolutionary relationships. This in turn limits efficient use of crop wild relatives in eggplant improvement. Here, we examine the hypothesis of linear step‐wise expansion of the eggplant group from Africa to Asia.Methods: We use museum collections to generate nuclear and full‐plastome data for all species of the Eggplant clade. We combine a phylogenomic approach with distribution data to infer a biogeographic scenario for the clade.Key Results: The Eggplant clade has Pleistocene origins in northern Africa. Dispersals to tropical Asia gave rise to Solanum insanum, the wild progenitor of the eggplant, and to African distinct lineages of widespread and southern African species. Results suggest that spread of the species to southern Africa has been recent and likely facilitated by large mammalian herbivores, such as the African elephant and impala feeding on Solanum fruit.Conclusions: Rather than a linear ‘Out Of Africa’ sequence, our results are more consistent with an initial dispersal event into Asia, and subsequent wide dispersal and differentiation across Africa driven by large mammalian herbivores. Our evolutionary results will affect future work on eggplant domestication and affect the use of wild relatives in breeding of this increasingly important solanaceous crop.
Premise: The economically important, cosmopolitan soapberry family (Sapindaceae) comprises ca. 1900 species in 144 genera. Since the seminal work of Radlkofer, several authors have attempted to overcome challenges presented by the family’s complex infra‐familial classification. With the advent of molecular systematics, revisions of the various proposed groupings have provided significant momentum, but we still lack a formal classification system rooted in an evolutionary framework.Methods: Nuclear DNA sequence data were generated for 123 genera (86%) of Sapindaceae using target sequence capture with the Angiosperms353 universal probe set. HybPiper was used to produce aligned DNA matrices. Phylogenetic inferences were obtained using coalescence‐based and concatenated methods. The clades recovered are discussed in light of both benchmark studies to identify synapomorphies and distributional evidence to underpin an updated infra‐familial classification.Key Results: Coalescence‐based and concatenated phylogenetic trees had identical topologies and node support, except for the placement of Melicoccus bijugatus Jacq. Twenty‐one clades were recovered, which serve as the basis for a revised infra‐familial classification.Conclusions: Twenty tribes are recognized in four subfamilies: two tribes in Hippocastanoideae, two in Dodonaeoideae, and 16 in Sapindoideae (no tribes are recognized in the monotypic subfamily Xanthoceratoideae). Within Sapindoideae, six new tribes are described: Blomieae Buerki & Callm.; Guindilieae Buerki, Callm. & Acev.‐Rodr.; Haplocoeleae Buerki & Callm.; Stadmanieae Buerki & Callm.; Tristiropsideae Buerki & Callm.; and Ungnadieae Buerki & Callm. This updated classification provides a backbone for further research and conservation efforts on this family.
Open science and open data within scholarly research programs are growing both in popularity and by requirement from grant funding agencies and journal publishers. A central component of open data management, especially on collaborative, multidisciplinary, and multi-institutional science projects, is documentation of complete and accurate metadata, workflow, and source code in addition to access to raw data and data products to uphold FAIR (Findable, Accessible, Interoperable, Reusable) principles. Although best practice in data/metadata management is to use established internationally accepted metadata schemata, many of these standards are discipline-specific making it difficult to catalog multidisciplinary data and data products in a way that is easily findable and accessible. Consequently, scattered and incompatible metadata records create a barrier to scientific innovation, as researchers are burdened to find and link multidisciplinary datasets. One possible solution to increase data findability, accessibility, interoperability, reproducibility, and integrity within multi-institutional and interdisciplinary projects is a centralized and integrated data management platform. Overall, this type of interoperable framework supports reproducible open science and its dissemination to various stakeholders and the public in a FAIR manner by providing direct access to raw data and linking protocols, metadata and supporting workflow materials.
Premise: A novel protocol for rapid plant DNA extraction using microneedles is proposed, which supports botanic surveys, taxonomy, and systematics. This protocol can be conducted in the field with limited laboratory skills and equipment. The protocol is validated by sequencing and comparing the results with QIAGEN spin‐column DNA extractions using BLAST analyses.Methods and Results: Two sets of DNA extractions were conducted on 13 species spanning various leaf anatomies and phylogenetic lineages: (i) fresh leaves were punched with custom polymeric microneedle patches to recover genomic DNA, or (ii) QIAGEN DNA extractions. Three plastid (matK, rbcL, and trnH‐psbA) and one nuclear ribosomal (ITS) DNA regions were amplified and sequenced using Sanger or nanopore technology. The proposed method reduced the extraction time to 1 min and yielded the same DNA sequences as the QIAGEN extractions.Conclusions: Our drastically faster and simpler method is compatible with nanopore sequencing and is suitable for multiple applications, including high‐throughput DNA‐based species identifications and monitoring.