1. cycloidea genes in sunflower
cycloidea in snapdragon and Lotus controls floral zygomorpgy (left-right symmetry of the flowers) - when these genes are knocked out the flower resembles an ancestrally polysymmetric flower.
A member of the same gene family in corn, teosinte branched1 (tb1) controls the difference in branching patterns between corn (single stem) and its progenitor teosinte (multiple branches).
In sunflower I am isolating these genes because...
... sunflower flower heads contain polysymmetric disc florets and zygomorphic ray florets. We also gained some evidence that a cycloidea-like gene controls the formation of ray florets in Senecio. Hence we wish to determine if cycloidea is involved in sunflower flower development. Currently I have isolated 10 cycloidea-like genes - three are only expressed in floral parts, and one is only expressed in ray florets (this was a nice result!) (Chapman et al., in press). Im now looking at floral mutants (ones with no rays, and ones that have elongated ray-like disc florets) in an attempt to confirm whether these genes play a role.
... cultivated sunflower in unbranched, whereas the wild sunflower has many side branches, superficially resembling the ddiference between maize and teosinte. Two of the cycloidea genes i have isolated show good homology to maize tb1 and currently I am examining their expression patterns and their position on published and unpublished linkage maps relative to branching QTL
2. Safflower
Safflower (Carthamus tinctorius L.) is a crop used for its oil, in dyes as well as for some medicinal reasons. We are investigating the genus Carthamus to identify the progenitor of this crop. Here is some interesting information about safflower. Using DNA sequencing we have confirmed the wild progenitor was C. palaestinus (Chapman and Burke, 2007b)
3. Universal markers
Phylogenetic and comparative mapping projects require PCR-based markers that can be amplified in a range of species, however show variation within species. We have developed a suite of such markers for use in the sunflower family (Chapman et al 2007). If youre working on a member of the Asteraceae and want to stuudy DNA variation please feel free to contact me.
4. Senecio Hybridization
Following from my Phd I am continuing my research into hybridization between Senecio aethnensis and S. chrysanthemifolius on Mt. Etna. Im looking at gene flow through the hybrid zone using 'random' nuclear markers (above) and also a set of four candidate genes that affect the fatty acid profiles of the seed. The seed fatty acids differ significantly between aethnensis and chrysanthemifolius and this affects their germination behaviour (unpublished data). Im hoping to combine sequence data of these genes with the seed lipids to show that the species are maintained as 'good' species due to ecological isolation.
And if I havent convinced you that these species are exciting enough, you should know that hybrids transplanted from Mt. Etna to England in ca. 1690 have become established as a diploid hybrid species (Senecio squalidus; James and Abbott, 2005). And then..... this hybridized with native Senecio vulgaris to form the introgressant S. vulgaris var. hibernicus, the tetraploid S. eboracensis and the hexaploid S. cambrensis. The latter formed twice as well!