Ya Yang

Premise Better understanding of the relationship between plant specialized metabolism and traditional medicine has the potential to aid in bioprospecting and untangling of cross‐cultural use patterns. However, given the limited information available for metabolites in most plant species, understanding medicinal use–metabolite relationships can be difficult. The order Caryophyllales has a unique pattern of lineages of tyrosine‐ or phenylalanine‐dominated specialized metabolism, represented by mutually exclusive anthocyanin and betalain pigments, making Caryophyllales a compelling system to explore the relationship between medicine and metabolites by using pigment as a proxy for dominant metabolism. Methods We compiled a list of medicinal species in select tyrosine‐ or phenylalanine‐dominant families of Caryophyllales (Nepenthaceae, Polygonaceae, Simmondsiaceae, Microteaceae, Caryophyllaceae, Amaranthaceae, Limeaceae, Molluginaceae, Portulacaceae, Cactaceae, and Nyctaginaceae) by searching scientific literature until no new uses were recovered. We then tested for phylogenetic clustering of uses using a “hot nodes” approach. To test potential non‐metabolite drivers of medicinal use, like how often humans encounter a species (apparency), we repeated the analysis using only North American species across the entire order and performed phylogenetic generalized least squares regression (PGLS) with occurrence data from the Global Biodiversity Information Facility (GBIF). Results We hypothesized families with tyrosine‐enriched metabolism would show clustering of different types of medicinal use compared to phenylalanine‐enriched metabolism. Instead, wide‐ranging, apparent clades in Polygonaceae and Amaranthaceae are overrepresented across nearly all types of medicinal use. Conclusions Our results suggest that apparency is a better predictor of medicinal use than metabolism, although metabolism type may still be a contributing factor.

Summary C 2 photosynthesis is characterised using recapturing photorespiratory CO 2 by RuBisCo in Kranz‐like cells and is therefore physiologically intermediate between C 3 and C 4 photosynthesis. C 2 can be interpreted as an evolutionary precursor of C 4 and/or as the result of hybridisation between a C 3 and C 4 lineage. We compared the expression of photosynthetic traits among populations of the Salsola divaricata agg. (C 2 ) from humid subtropical to arid habitats on the coasts of the Canary Islands and Morocco and subjected them to salt and drought treatments. We screened for enhanced C 4 ‐like expression of traits related to habitat or treatment. We estimated species trees with a transcriptome dataset of Salsoleae and explored patterns of gene tree discordance. With phylogenetic networks and hybridisation analyses we tested for the hybrid origin of the Salsola divaricata agg. We observed distinct independent variation of photosynthetic traits within and among populations and no clear evidence for selection towards C 4 ‐like trait expression in more stressful habitats or treatments. We found reticulation and gene tree incongruence in Salsoleae supporting a putative hybrid origin of the Salsola divaricata agg. C 2 photosynthesis in the Salsola divaricata agg. combines traits inherited from its C 3 and C 4 parental lineages and seems evolutionarily stable, possibly well adapted to a wide climatic amplitude.