David vs Goliath: searching for genetic markers underlying growth form, life-history and correlating features using a crossing experiment in cabbage (Brassica oleracea)
What is the genetic mechanism behind woodiness and associated characteristics such as flowering time, drought stress resistance, stem elongation, ageing, and plant herbivory?
- F.P. Lens
- Naturalis Biodiversity Center
- Plant Ecology and Phytochemistry
Why are there so many phenotypic differences between woody and herbaceous species? To this day, scientists have failed to provide satisfying answers. We have crossed a tall, woody, late flowering cabbage accession (Jersey kale) with a small, rapid flowering cabbage accession (TO1000) to find genomic regions associated with the phenotypic differences observed in the F2 generation (QTL experiment). A number of phenotypic differences that interests us are woodiness, flowering time, developmental speed, drought stress resistance, stem elongation, ageing, and plant herbivory.
An ongoing global database has revealed hundreds of independent evolutionary transitions from herbaceousness towards derived woodiness in flowering plants and highlights that most of these woody species occur in continental re
gions with a marked drought period. Brassicaceae, with Arabidopsis thaliana as a famous model species, is the number two family in terms of number of these growth form transitions in flowering plants, making the family an excellent case study to investigate the genetic mechanism behind phenotypic differences between closely related woody and herbaceous species that differ strongly in morphological and life-history characteristics.
The frequent evolutionary shifts towards derived woodiness suggest that the genetic mechanism should be relatively simple, which is supported by a shrub-like woody mutant of Arabidopsis thaliana in which two genes (SOC1 & FUL) are knocked out. Also in Brassica oleracea, some island accessions develop into woody, walking stick cabbages extending up to 3-4m tall, while others are small and produce much less wood. These differences in woodiness are associated with major changes in life-history characteristics.
We have set up a tissue culture line of a cross consisting of the Jersey kale – a giant, late-flowering, walking stick accession (Goliath), with TO1000 – a small, rapid flowering accession (David). The F1 generation is similar in growth form but shows more than six months difference in flowering time, owing to the heterozygosity of the Jersey kale parent. The reciprocal cross of an early and a late flowering F1 is being initiated, and a huge phenotypic difference in the F2 generation is expected.
SNP calling of the parents is ongoing, necessary to make the genetic map based on the F2 individuals. Phenotyping the F2 generation will be done in cooperation with our partners, each having specific research questions related to woodiness, flowering time, drought stress resistance, stem elongation, ageing, and plant herbivory.
Additional Researchers list
- Davin N, Hefer CA, Edger PP, Mizrachi E, Schuetz M, Smets E, Myburg AA, Douglas CJ, Schranz ME, Lens F. 2016. Functional network analysis of genes differentially expressed during xylogenesis in soc1ful woody Arabidopsis plants. The Plant Journal 86: 376-390
- De Jong TJ, Klinkhamer PGL. 2005. Evolutionary ecology of plant reproductive strategies. Cambridge University Press
- Dória LC, Podadera DS, del Arco M, Chauvin T, Smets E, Delzon S, Lens F. 2018. Insular woody daisies (Argyranthemum, Asteraceae) are more resistant to drought-induced hydraulic failure than their herbaceous relatives. Functional Ecology DOI: 10.1111/1365-2435.13085
- Lin T, Klinkhamer PGL, Vrieling K. 2017. Parallel evolution in an invasive plant: effect of herbivores on competitive ability and regrowth of Jacobaea vulgaris. Ecology Letters: 18: 668-676
- Melzer S, Lens F, Gennen J, Vanneste S, Rhode A, Beeckman T. 2008. Flowering-time genes modulate meristem determinacy and growth form in Arabidopsis. Nature Genetics 40: 1489-1492