Přednáška z Anatomie a fyziologie rostlin

datum 18.11.2014
přednáší RNDr. Jan Petrášek, Ph.D. (KEBR PřF UK a ÚEB AV ČR, Praha)
název Differential plasma membrane dynamics of auxin influx and efflux carriers in tobacco cells
anotace The generation of auxin concentration gradients is important for numerous aspects of plant development. A significant proportion of auxin action is regulated by carrier-mediated cell-to-cell auxin transport that is controlled by the dynamic localization of plasma membrane (PM) auxin carriers. However, the knowledge on the mechanisms determining the mobility of auxin carriers within the PM is still limited. Here we used the combination of fluorescence microscopy methods to follow the PM dynamics of Arabidopsis thaliana auxin influx and efflux carriers EYFP:AUX1 and PIN1:GFP heterologously expressed under inducible promoters in the cells of Nicotiana tabacum cv. Bright Yellow 2 (BY-2). Although fluorescence recovery after photobleaching (FRAP) showed that for both AUX1 and PIN1 the proportion of mobile PM fraction is quite low, raster image correlation spectroscopy (RICS) revealed that PIN1 is more dynamic then AUX1 within this mobile fraction. Pharmacological treatments uncovered that the mobility of PIN1 depends on actin and microtubular cytoskeleton, while AUX1 mobility depends largely on sterol composition of the PM. Auxin transport assays suggested that cytoskeleton-dependent dynamics of auxin transporters affects partly carrier-mediated auxin efflux, but not auxin influx. Alltogether, we have uncovered new cytoskeleton-dependent mechanisms for both dynamics and function of auxin efflux carriers from PIN family.

This work is supported by the Czech Science Foundation; project GAP305/11/2476.

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