Thesis defence

Hany El-Sayed Bashandy

“Flavonoid metabolomics in Gerbera hybrida and elucidation of complexity in the flavonoid biosynthetic pathway”

Saturday, 23rd January at 12 in Lecture room B7, (Viikki B building, Latokartanonkaari 7)

It wasn’t a transposon!

Ivory_revertantAnthocyanin biosynthesis in gerbera cultivar ‘Estelle’ and its acyanic sport ‘Ivory’

Hany Bashandy, Milla Pietiäinen, Elisabete Carvalho, Kean-Jin Lim, Paula Elomaa, Stefan Martens and Teemu H. Teeri


Planta 2015; DOI: 10.1007/s00425-015-2349-6

Identification of distinct allelic versions for dihydroflavonol 4-reductase in gerbera cultivars reveals that gerbera DFR enzymes have strong substrate preference in vivo that is not reflected to the activity in vitro.

Flavonoids in the model ornamental plant Gerbera hybrida consist of flavones, flavonols and anthocyanins. Anthocyanins accumulate in the adaxial epidermis of petals and give the different cultivars their characteristic red and violet colour. Both pelargonidin and cyanidin derivatives are found in gerbera, but none of the cultivars contain delphinidin. ‘Ivory’, a cultivar with white petals, is a sport of the pelargonidin-containing pink cultivar ‘Estelle’, i.e. it originates from an acyanic branch of ‘Estelle’. In this work, four different alleles encoding dihydroflavonol 4-reductase (DFR) were identified in gerbera cultivars. We found that, in contrast to ‘Estelle’ with the functional allele GDFR12, ‘Ivory’ carries a mutation in this gene that results in an inactive enzyme. Interestingly, ‘Ivory’ also expresses a second, nonmutated allele (GDFR13) in petal epidermi, leading to extractable DFR activity but not to anthocyanin biosynthesis. The second allele encodes a protein identical in amino acid sequence to the DFR of the cyanidin-containing variety ‘President’. Pelargonidin-containing cultivars do not react to the flavonoid 3′-hydroxylase inhibitor tetcyclacis, but cyanidin-containing cultivars lose their colour, instead of starting to synthesise pelargonidins, indicating the specificity of GDFR1-3 for the cyanidin pathway. This explains why petals of ‘Ivory’ are white, even when it has lost only one of the two enzymatically functional DFR forms, and shows that anthocyanin biosynthesis in gerbera is under more complex regulation than earlier thought.

Two special seminars hosted by the Gerbera lab

Monday 18.5.2015, seminar room C130 (Latokartanonkaari 5, C-building, 1st floor)

10.15-11.00 Prof. Annette Becker, Justus-Liebig University, Giessen, Germany: Molecular evolution of carpel developmental toolkit

11.00-11.45 Dr. Oriane Hidalgo, Royal Botanic Gardens, Kew, UK: Evolutionary-developmental insights into the inflorescences of Papaveraceae and Asteraceae