P026
Membrane sterols play essential roles in stress response
of plant cells
Albina Sulkarnayeva, Julia Valitova,
Fakhima Mukhitova, Anastasia Ponomareva and
Farida Minibayeva
Kazan Institute of Biochemistry and Biophysics, Kazan,
Russian Federation
Plant cells contain a complex mixture of membrane sterols (βsitosterol, campesterol, stigmasterol, cholesterol). Sterols are not
only the structural elements of membranes but also components
of signaling pathways, which are involved in the regulation of
growth, development and stress responses of plants. A useful
experimental approach for elucidating the roles of sterols in
membrane activity is the application of agents that specifically
bind with endogenous sterols, such as methyl-β-cyclodextrine
(MeβCD) and nystatin. In present work, despite of their similar
ability to reduce the sterol content, these agents had different
influence on membrane permeability for ions, cellular oxidative
status, induction of autophagy, and cell viability in the roots of
wheat seedlings. The effects of channel-forming nystatin were
more toxic than that of MeβCD for plants. Therefore, the disturbance of membrane integrity rather than the decrease in the
sterol content is responsible for the toxicity of sterol-binding
compounds. Furthermore, the significant changes in the levels of
sterol molecular species and the activity of a gene encoding the
key enzyme of plant sterol synthesis C24-sterol methyltransferase
(TaSMT1) were found in the roots of wheat (Triticum aestivum
L.) seedlings following cold, wounding and oxidative stresses.
Partial sequencing and analysis of promoter region of TaSMT1
revealed the presence several stress responsive cis-elements.
In conclusion, sterols are important players in stress response of
plant cells.