Lucio Conti - The A-B-A of the floral transition: role of abscisic acid in developmental reprogramming under varying water scenarios
- Datum: 13.06.2018
- Uhrzeit: 14:00 - 15:30
- Vortragende(r): Lucio Conti
- Ort: Central Building
- Raum: Seminar Room
- Gastgeber: Aleksandra Skirycz
Among the different environmental
factors influencing plant development, the effects of water scarcity
are extremely relevant in today’s science for their implications with the
ongoing climate change. Under
natural conditions, plants can evade water deficit by synchronising the onset
of reproductive
development with the rainy season. In temperate climates, characterised by dry
summers, this usually
involves the selection for early flowering genotypes that can effectively
escape the summer drought.
Such drought escape strategy (DE) can be adaptive. This means that upon drought
stress some plants
can utilise drought signals as a cue to hasten their life cycle, thereby
anticipating potentially lethal stress
conditions.
Our work is centred upon the study of the molecular events underpinning the DE
phenomenon in
Arabidopsis with the long-term goal of revealing their conservation in crops.
Two signalling components
form the basic structure of the DE response; the photoperiodic gene GIGANTEA
(GI), and the droughtrelated
phytohormone abscisic acid (ABA). GI and ABA converge upon the transcriptional
activation
of the florigen genes FT and TSF. The activation of FT is usually mediated by
CONSTANS (CO). I will
thus discuss the potential ABA-dependent mode of activation of GI signaling and
its connection with
CO function in the leaf. Another related topic pertains the regulation of ABA
targets outside the leaf and
their role in the floral transi tion. The study of mutants defective in ABA
signalling suggests that ABA
has multiple roles in flowering, some of which are exerted in the shoot apical
meristem. In this spatial
context, I plan to illustrate the role of a class of ABA-regulated bZIP
transcription factors which are
structurally related to the flowering protein FD.
In summary, besides the key role upstream of FT, ABA is connected with the
flowering network at
multiple points. Since contrasting flowering responses have been reported in
nature and in crops under
varying drought scenarios, our data suggest that plants may utilize ABA signals
in different ways to
coordinate flowering time according to the prevailing watering conditions.