Fruit evolution and adaptation to Mediterranean habitats in Raphanus (Brassicaceae)

• Applicant: Professor Dr. Klaus Mummenhoff
• Subject Area: Evolution and Systematics of Plants and Fungi ; Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 288490669

• Final Report Year: 2024

Final Report Abstract

The two genetically close wild radishes, "Raphanus raphanistrum" and "R. pugioniformis", differ in fruit structure and dispersal units. Dispersal experiments supported the ability of R. raphanistrum for long-distance dispersal by wind and running water, explaining ist wide local and global distribution. In contrast, the relatively large and heavy fruits of R. pugioniformis disperse only short distances, consistent with ist limited distribution and possibly ist endemic nature. Botanical surveys conducted within the scope of this project indicated that populations of R. pugioniformis are characterized by a patchy spatial structure, whereas the relatively large populations of R. raphanistrum show a more uniform structure. Genotyping-by-sequencing (GBS) confirmed our assumption that long-distance dispersal across homogeneous environments (R. raphanistrum) versus short-distance dispersal in heterogeneous habitats (R. pugioniformis) influences the genetic structure within and among populations. Furthermore, single nucleotide polymorphism (SNP) loci associated with directional selection and environmental conditions were more pronounced in R. pugioniformis, indicating local adaptation. Results of a common garden experiment, which showed variation in phenological traits only among populations of R. pugioniformis and their association with climatic variables, provided further support for local adaptation. Finally, phenotypic differentiation in root morphology and growth indicated adaptations to specific edaphic conditions. Thus, altogether, the results of this project provide evidence for the link between speciation and local adaptation in two genetically close species.

Publications

• Molecular phylogeny indicates polyphyly in Raphanus L. (Brassicaceae). Edinburgh Journal of Botany, 72(1), 1-11.
  Ziffer-Berger, J.; Hanin, N.; Fogel, T.; Mummenhoff, K. & Barazani, O.
  
• Seed dispersal of wild radishes and its association with within-population spatial distribution. BMC Ecology, 20(1).
  Ziffer-Berger, J.; Waitz, Y.; Behar, E.; Ben, Joseph O.; Bezalel, L.; Wasserstrom, H.; Bajpai, P. K.; Bhattacharya, S.; Przesdzink, F.; Westberg, E.; Mummenhoff, K. & Barazani, O.
  
• Phenotypic variation of wild radishes Raphanus pugioniformis and R. raphanistrum associated with local conditions in the southeast Mediterranean. Flora, 287, 151997.
  Wasserstrom, Haggai; Berger, Jotham Ziffer; Barzilai, Michal; Mummenhoff, Klaus & Barazani, Oz
  
• ‘Root of all success’: Plasticity in root architecture of invasive wild radish for adaptive benefit. Frontiers in Plant Science, 13.
  Bhattacharya, Samik; Gröne, Franziska; Przesdzink, Felix; Ziffer-Berger, Jotham; Barazani, Oz; Mummenhoff, Klaus & Kappert, Niels