Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)
Jeudi 24 avril 2014
Amphi 2 (Bâtiment 2 Bis) à 14h
Hormonal regulation of root system architecture
Institute of Science and Technology Austria Austria, Am Campus 1, 3400 Klosterneuburg, Austria
The plant hormones auxin and cytokinin are central endogenous signaling molecules that regulate lateral root organogenesis. Stimulatory effect of auxin is counterbalanced by cytokinin, and thus, tight control and mutual balance of their antagonistic activities are particularly important during the early phases of lateral root organogenesis to ensure continuous lateral root initiation and proper development of lateral root primordia. Our studies reveal how cytokinin contributes to spatiotemporal regulation of lateral root organogenesis. We analyzed cytokinin and cytokinin signaling distribution along the root and show that the early phases of lateral root organogenesis including priming and initiation take place in the root zone with strongly repressed cytokinin responses. Enhancement of the cytokinin activity in the zone encompassing the basal meristem inhibits most efficiently lateral root initiation, but when increased in the mature differentiated parts of the roots cytokinin interfered with the development, but not initiation of lateral roots. In contrast, cytokinin response is enhanced in the pericycle cells neighboring the lateral root primordia and we propose that this cytokinin activity is critical to prevent initiation in close proximity of existing primordia. Further progress in our understanding of auxin-cytokinin crosstalk in regulation of root system architecture will be discussed.
Contact : Benoît Lacombe