On the hybrid origin of the C2 Salsola divaricata agg. (Amaranthaceae) from C3 and C4 parental lineages

  • Delphine T. Tefarikis (Creator)
  • Diego F. Morales-Briones (Ludwig-Maximilians-Universit√§t M√ľnchen) (Creator)
  • Ya Yang (Creator)
  • Gerald Edwards (Creator)
  • Gudrun Kadereit (Creator)



C<sub>2</sub> photosynthesis is characterized by recapturing photorespiratory CO<sub>2</sub> by RuBisCO in Kranz-like cells and is therefore physiologically intermediate between C<sub>3</sub> and C<sub>4</sub> photosynthesis. C<sub>2</sub> can be interpreted as an evolutionary precursor of C<sub>4</sub> and/or as the result of hybridization between a C<sub>3</sub> and C<sub>4</sub> lineage.
We compared the expression of photosynthetic traits among populations of the <em>Salsola divaricata </em>agg. (C<sub>2</sub>) 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<sub>4</sub>-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 hybridization analyses we tested for hybrid origin of the <em>Salsola divaricata </em>agg.
We observed distinct independent variation of photosynthetic traits within and among populations and no clear evidence for selection towards C<sub>4</sub>-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 <em>Salsola divaricata </em>agg.
C<sub>2</sub> photosynthesis in the <em>Salsola divaricata </em>agg. combines traits inherited from its C<sub>3</sub> and C<sub>4</sub> parental lineages and seems evolutionarily stable, possibly well adapted to a wide climatic amplitude.
Date made available2022

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