Role of cytoskeleton in mediating the action of abiotic factors on plant cells

Work number - M 47 AWARDED

Authors:Krasylenko Y.A. , Horiunova I.I., Plohovskaya S.H.

Presented by the Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine

The cycle of scientific works consists of 24 research papers and 3 chapters in monographs published during the 2009–2018.

Plant lifeactivityand productivityareregulatedby a plethora of defensive cell mechanisms allowing plants to counteract adverse environmental сonditions. Among the key  abiotic factors affecting plantfitness are theheavy metals accumulation, low/high temperatures,and UV-B. The study of the adaptation mechanisms is crucial for the enhancement ofcertain signalling pathways toimprove plant yield undervarious stress conditions.Cytoskeleton is a mechanic force of cell morphogenesis as well as highly sensitive and dynamic signaling cascade link of plant cell (a)biotic stress response. In a current work, we have summarized the results on the effects of nitric oxide (NO) content modulators, an NO-synthase inhibitor, marker of NO activity as well as UV-B, toxic metals, low temperatures on growth, morphology and in vivo organization of cytoskeleton components of Arabidopsis thaliana roots. It was found that cortical microtubules in cells of transition and elongation zones of A. thaliana (GFP-MAP4) primary roots is the most sensitive to changes of NO content. Tyrosine nitration of plant α-tubulin and decoration of mitotic figures by 3-nitrotyrosine was shown for the first time. UB-B-triggered disturbances of A. thaliana root growth and morphology together with the dramatic changes of microtubules organization were described. Moreover, we have establish the functional link between the NO content and microtubule stability under UV-B exposure. It was shown for the first time that actin filaments and microtubules of A. thaliana cells are sensitive to the increase of Cd²⁺, Ni²⁺ , Zn²⁺ and Cu²⁺ concentration. Cd²⁺ affected microtubules mostly in apical meristem and transition zone cells,  Ni²⁺– in meristem and elongation zone, Cu²⁺ – only in meristem, while Zn²⁺ – predominantly in transition zone. In turn, microfilaments in cells of meristem and transition zone were the most sensitive to Cd²⁺, Ni²⁺ – of meristem and elongation zone, Zn²⁺ – of transition zone, and Cu²⁺ – of differentiation zone. It was found that heavy metals directly affects microtubules, what can be one the reasons of  time- and concentration-dependent changes of root growth and morphology. Furthermore, in vivo organization of actin filaments in A. thaliana (GFP-ABD2-GFP) cell after the exposure of seedlings to low temperatures (0.5–4⁰C) was studied for the first time. The most susceptible this abiotic stress were actin microfilaments in root hairs, and also epidermal cells of division and elongation zones. Our data demonstrates the negative impact of the combined effect of low temperature and NO-scavenger on microfilaments organization analyzed by MFA software, while the exposure to cold causes actin filaments reorientation and changes of polymerization state of actin in root cells.Generally, our studies provide novel data on mechanisms of plant stress response mediated by cytoskeleton as the universal component of signaling pathways triggered by changes of nitric oxide content,heavy metals, UV-B and low temperatures.

The results of studies on the subject are set out in 1 chapter in monograph, 24 articles (including 12 in foreign journals) and 41abstracts. Total number of publications of the authors is 68.

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