ACTIN CYTOSKELETON REARRANGEMENTS DURING THE GRAVITROPIC RESPONSE OF ARABIDOPSIS ROOTS
Pozhvanov G.A.,1,2,* Suslov D.V.,1 Medvedev S.S.1
1 Saint-Petersburg State University, Faculty of Biology and Soil Sciences, Department of Plant Physiology and Biochemistry, and
2 Komarov Botanical Institute RAS, Saint-Petersburg;
* e-mail: gregory@pozhvanov.com
Gravitropic response is a plant growth response against changing its position relative to the gravity vector. In the present work we studied actin cytoskeleton rearrangements
during Arabidopsis root gravitropic response. Two alternative approaches were used to visualize actin microfilaments: histochemical staining of fixed roots with
rhodamine-phalloidin and live imaging of microfilaments in GFP-fABD2 transgenic plants. The curvature of actin microfilaments was shown to be increased within 30-60 min of g
ravistimulation, the fraction of axially oriented microfilaments decreased with a concomitant increase in the fraction of oblique and transversally oriented microfilaments.
Methodological issues of actin cytoskeleton visualization in the study of Arabidopsis root gravitropic response, as well as the role of microfilaments at the stages of gravity perception,
signal transduction and gravitropic bending formation are discussed. It is concluded that the actin cytoskeleton rearrangements observed are associated with the regulation of basic
mechanisms of cell extension growth by which the gravitropic bending is formed.
Key words: Arabidopsis thaliana, gravitropism, cytoskeleton, actin, root, extension growth
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