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The evening primrose family (Onagraceae) includes 664 species (803 taxa) with a center of diversity in the Americas, especially western North America. Ongoing research in Onagraceae includes exploring striking variation in floral morphology, scent composition, and breeding system, as well as the role of these traits in driving diversity among plants and their interacting pollinators and herbivores. However, these efforts are limited by the lack of a comprehensive, well-resolved phylogeny. Previous phylogenetic studies based on a few loci strongly support the monophyly of the family and the sister relationship of the two largest tribes but fail to resolve several key relationships.

We used a target enrichment approach to reconstruct the phylogeny of Onagraceae using 303 highly conserved, low-copy nuclear loci. We present a phylogeny for Onagraceae with 169 individuals representing 152 taxa sampled across the family, including extensive sampling within the largest tribe, Onagreae. Deep splits within the family are strongly supported, whereas relationships among closely related genera and species are characterized by extensive conflict among individual gene trees.

This phylogenetic resource will augment current research projects focused throughout the family in genomics, ecology, coevolutionary dynamics, biogeography, and the evolution of characters driving diversification in the family.

 

Oenothera sect. Calylophus is a North American group of 13 recognized taxa in the evening primrose family (Onagraceae) with an evolutionary history that may include independent origins of bee pollination, edaphic endemism, and permanent translocation heterozygosity. Like other groups that radiated relatively recently and rapidly, taxon boundaries within Oenothera sect. Calylophus have remained challenging to circumscribe. In this study, we used target enrichment, flanking noncoding regions, gene tree/species tree methods, tests for gene flow modified for target-enrichment data, and morphometric analysis to reconstruct phylogenetic hypotheses, evaluate current taxon circumscriptions, and examine character evolution in Oenothera sect. Calylophus. Because sect. Calylophus comprises a clade with a relatively restricted geographic range, we were able to extensively sample across the range of geographic, edaphic, and morphological diversity in the group. We found that the combination of exons and flanking noncoding regions led to improved support for species relationships. We reconstructed potential hybrid origins of some accessions and note that if processes such as hybridization are not taken into account, the number of inferred evolutionary transitions may be artificially inflated. We recovered strong evidence for multiple evolutionary origins of bee pollination from ancestral hawkmoth pollination, edaphic specialization on gypsum, and permanent translocation heterozygosity. This study applies newly emerging techniques alongside dense infraspecific sampling and morphological analyses to effectively reconstruct the recalcitrant history of a rapid radiation. [Gypsum endemism; Oenothera sect. Calylophus; Onagraceae; phylogenomics; pollinator shift; recent radiation; target enrichment.]

 

Limited work to date has examined plastic ingestion in highly migratory seabirds like Great Shearwaters ( Ardenna gravis ) across their entire migratory range. We examined 217 Great Shearwaters obtained from 2008–2019 at multiple locations spanning their yearly migration cycle across the Northwest and South Atlantic to assess accumulation of ingested plastic as well as trends over time and between locations. A total of 2328 plastic fragments were documented in the ventriculus portion of the gastrointestinal tract, with an average of 9 plastic fragments per bird. The mass, count, and frequency of plastic occurrence (FO) varied by location, with higher plastic burdens but lower FO in South Atlantic adults and chicks from the breeding colonies. No fragments of the same size or morphology were found in the primary forage fish prey, the Sand Lance ( Ammodytes spp., n = 202) that supports Great Shearwaters in Massachusetts Bay, United States, suggesting the birds directly ingest the bulk of their plastic loads rather than accumulating via trophic transfer. Fourier-transform infrared spectroscopy indicated that low- and high-density polyethylene were the most common polymers ingested, within all years and locations. Individuals from the South Atlantic contained a higher proportion of larger plastic items and fragments compared to analogous life stages in the NW Atlantic, possibly due to increased use of remote, pelagic areas subject to reduced inputs of smaller, more diverse, and potentially less buoyant plastics found adjacent to coastal margins. Different signatures of polymer type, size, and category between similar life stages at different locations suggests rapid turnover of ingested plastics commensurate with migratory stage and location, though more empirical evidence is needed to ground-truth this hypothesis. This work is the first to comprehensively measure the accumulation of ingested plastics by Great Shearwaters over the last decade and across multiple locations spanning their yearly trans-equatorial migration cycle and underscores their utility as sentinels of plastic pollution in Atlantic ecosystems. 

Nyctaginaceae are one of the most diverse families in core Caryophyllales. The most diagnostic character of the family is a persistent anthocarp derived from a calyx-like perianth. Anthocarp morphology is highly variable across the family, but its evolution is poorly studied. We investigate anthocarp evolution in Nyctaginaceae through extensive anatomical studies (159 species from 28 genera representing six of seven tribes) and phylogenetic character state reconstructions. We found highly diverse anthocarp anatomy across Nyctaginaceae, with most traits analysed evolving multiple times throughout the family. The representatives of three early-diverging clades of Nyctaginaceae (Leucastereae, Boldoeae and Colignonieae) possess a calyx-like anthocarp with simplified anatomy. The so-called ‘glands’ in Nyctagineae and Pisonieae are emergences, whereas wings originate by accrescence of perianth segments, elongation of the ribs and outgrowths (emergences) of anthocarp mesophyll. Anthocarp anatomy can be considered as a generic-level feature in Colignonieae, Pisonieae, Bougainvilleeae and Nyctagineae. The most dramatic transitions from perianth to anthocarp involve the shrivelling and abscission of the upper perianth part and the maintenance of the basal modified perianth portion that originated in the clade comprising Colignonieae and sister clades.

 

The evolution ofl‐DOPA4,5‐dioxygenase activity, encoded by the geneDODA, was a key step in the origin of betalain biosynthesis in Caryophyllales. We previously proposed thatl‐DOPA4,5‐dioxygenase activity evolved via a single Caryophyllales‐specific neofunctionalisation event within theDODAgene lineage. However, this neofunctionalisation event has not been confirmed and theDODAgene lineage exhibits numerous gene duplication events, whose evolutionary significance is unclear.

To address this, we functionally characterised 23 distinctDODAproteins forl‐DOPA4,5‐dioxygenase activity, from four betalain‐pigmented and five anthocyanin‐pigmented species, representing key evolutionary transitions across Caryophyllales. By mapping these functional data to an updatedDODAphylogeny, we then explored the evolution ofl‐DOPA4,5‐dioxygenase activity.

We find that lowl‐DOPA4,5‐dioxygenase activity is distributed across theDODAgene lineage. In this context, repeated gene duplication events within theDODAgene lineage give rise to polyphyletic occurrences of elevatedl‐DOPA4,5‐dioxygenase activity, accompanied by convergent shifts in key functional residues and distinct genomic patterns of micro‐synteny.

In the context of an updated organismal phylogeny and newly inferred pigment reconstructions, we argue that repeated convergent acquisition of elevatedl‐DOPA4,5‐dioxygenase activity is consistent with recurrent specialisation to betalain synthesis in Caryophyllales.