Here are more infos on my PhD thesis...

Last update: October 22, 1998

For the non-specialists...

The idea is to study Forsythia, the way this marvellous plants produces flavonoid pigments (that is, compounds taking to red, orange or blue colors), to eventually, hopefully, MAYBE change its flower color to any (most probably red) of the previously cited hues. What? What's Forsythia? Click here to discover the popular bright-yellow, early-flowering bush that you maybe have in your back yard...

"Why?", is the most common question I've been asked since the beginning of my work. "Yellow Forsythias are so nice..."
"Why not!" is my answer! Man has pursued novelties, discoveries and inventions since the beginning of his history. Japanese people would spend a fortune for a BLUE rose, so: why not a RED (or ORANGE) Forsythia?... Moreover, no red-flowered plants are present at such an early time of spring. Our new Forsythia would fill the gap...

Not persuaded? Write me, we'll discuss more extensively about it!


... and for the specialists!

I worked on my PhD thesis in Molecular Biology Forsythia from January 1995 to December 1997. My tutor, Mr. Duron, first developed an efficient transformation protocol for this ornamental species (described in Rosati et al., 1996. Plant Cell Reports 16(1-2):114-117).
The major subject of my PhD was the molecular and biochemical investigation of the flavonoid pathway in Forsythia, to point out the causes for the lack of anthocyans in Forsythia petals (whose yellow color is due to the accumulation of carotenoids), to hopefully develop a successful transformation strategy to modify petal color.

To do so, I've cloned some Forsythia flavonoid pathway genes, ( chs, dfr , ans ) and analyzed their expression throughout flower development by Northern blot, rtPCR and competitive PCR. On the basis of results, DFR should not be responsible for the lack of flavonoid pigments in petals. This assumption is confirmed by the phenotype of transformed plants carrying a 35S CaMV promoter-driven DFR cds of Antirrhinum majus, which displayed yellow (i.e., wild type) petals. These results are described more in detail in Rosati et al., 1997. Plant Mol Biol 35: 303-311.
Therefore, the block should be at another level - ANS? regulatory genes?...
rtPCR analyses pointed out a transcriptional block of ans in anthers and petals. This could explain the lack of anthocyanins in these organs. The analysis of ans gene promoter has revealed several potential DNA-protein binding sites... further analyses are in progress...

Enzymatic tests (at prof. Forkmann's lab, TUM Freising, Germany) and HPLC analyses (at Dr. M.-J. Amiot's lab, INRA Avignon, France) have confirmed and completed molecular data, and will determine a possible substrate-specificity of DFR, leading to the formation of 3'4'-hydroxylated compounds, the major fraction of the flavonoid pool. All these results have recently been accepted for publication in Plant Science (an Elsevier journal) and will soon be available. Its reference? Rosati C. et al., 1998 or 1999. Flavonoid metabolism in Forsythia. Plant Sci, in press.

To make a VERY long story shorter, ongoing work concerns:

  1. further analyses of the ans promoter and of ans allelic diversity among several Forsythia genotypes of the INRA Angers' collection;
  2. investigations on DFR at the protein level (currently testing DFR antibodies kindly provided by Dr. De Jaeger, University of Gent, Belgium);
  3. transformation of wt and DFR transgenic Forsythia plants with CaMV 35S promoter-driven ANS;
  4. cloning and characterization of Forsythia ufgt gene(s) and its encoded enzyme.


Collaborations are the basis of research. Angers and Freising groups have been collaborating since 1996, actively exchanging people, results and tools to progress in fundamental and applied research on flower color.
Here are some pics following last summer's Eucarpia Ornamentals Symposium in Angers, displaying Angers' and Freising's staff collaborating on the "Forsythia project"...

In the haploid apple field in Angers Featuring Stefan Martens (prof. Forkmann's PhD student, pink T-shirt), Alain Cadic (Head of INRA Angers Ornamental Breeding Unit, white T-shirt), Michel Duron (my former PhD Tutor, INRA Angers Ornamental Breeding Unit, yellow sweater) and Gert Forkmann (Professor at University of Munich, Freising-Weihenstephan, grey jacket)

In the Forsythia tunnel - 1 Dr. Philippe Simoneau (University of Angers, blue shirt) and prof. Forkmann with his PhD students Regine Hasselpflug and Christian

In the Forsythia tunnel - 2 Mr. Cadic and Prof. Forkmann discussing about Forsythia's future...

In the Forsythia tunnel - 3 Philippe Simoneau, Michel Duron and Regine Hasselpflug: a closer look to transgenic Forsythias

Even if I'm presently gone, my collaboration with Angers' - and Freising's as well - researchers continues. More infos/details/discussion/collaboration?
Send me an e-mail...

... to be continued...