1. PhD Studentship available now METABOLIC REGULATION OF FLOWERING
2. Supervisors: Drs. D Francis, HJ Rogers; (School of Biosciences,
Cardiff University, Dr RJ Herbert, (University College, Worcester)
3. Project description
Flowering is an economically important process, since much of what
mankind eats is either plant seeds and fruit (which depend on
flowering) or storage organs (which depend on the prevention of
flowering). Induction of flowering is an environmentally regulated
process, and although much is known about genes that specify the
formation of floral organs (1) very little is known about signalling
pathways that lead to the expression of these genes nor about the
substrates upon which these genes act. Investment by Worcester in a
previous collaborative studentship has led to exciting discoveries
about the timing of floral organ appearance in a model plant species.
(Pharbitis nil, a short-day plant). Using a tissue culture based
system, we have found that the outer organs of the flower (sepal,
petal and stamen `whorls') are determined simultaneously within one
day of a 48h florally inductive treatment. However, most
surprisingly, the female reproductive organs (carpels) were not
determined until five days later. This is an important and exciting
discovery because previous work had indicated that all floral organs
were determined simultaneously (2). Significantly, a specific
carbohydrate at a specific concentration (3% w/v glucose) in the
culture medium shortened carpel determination time to such an extent
that the carpels were determined at the exactly the same time as the
other floral organs. We now wish to discover the mechanism whereby
glucose treatment results in the expression of carpel identity genes .
Moreover, another collaborative studentship is making substantial
progress on resolving floral genes in another model species (Silene
coeli-rosa, a long-day plant). Hence were are now in a powerful
position to exploit the Pharbitis system to understand the molecular
basis of the metabolic regulation of flowering. Existing genetic
models for flower development feature a gene (AGAMOUS) which specifies
stamen and carpel formation (3) The results of our experiments suggest
the activation of other important genes which specify carpels and that
these genes can be regulated by specific carbohydrate signals.
References
1. Meyerowitz EM (1997) Cell 88, 299-3082. Larkin JC et al. (1990)
Dev, Biol. 137, 434-4433. Coen E. EM (1991) ARev Pl Physiol 42,
241-279.
4. Facilities
All tissue culture facilities required are available both at Worcester
and Cardiff. All molecular biology facilities required are available
at Cardiff.
We are seeking a well qualified graduate in biological sciences (
2:1/First). A knowledge of plant molecular biology would be an
advantage but the project will provide comprehensive training
molecular and tissue culture techniques. Informal inquiries can be
made by contacting
Dennis Francis, Cardiff School of Biosciences(01222 875086 fax 01222
874305 email: [log in to unmask] Hilary J Rogers, Cardiff School
of Biosciences(01222 876352 email: [log in to unmask] Robert
Herbert ( 01905 855215, email: [log in to unmask]
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