Nitric oxide as a critical factor for perception of UV‐B irradiation by microtubules in Arabidopsis

Abstract

Influence of ultraviolet-B (UV-B) as an abiotic stress factor on plant microtubules (MTs) and involvement of nitric oxide (NO) as a secondary messenger mediating plant cell response to environmental stimuli were investigated in this study. Taking into account that endogenous NO content in plant cells has been shown to be increased under a broad range of abiotic stress factors, the effects of UV-B irradiation and also the combined action of UV-B and NO donor sodium nitroprusside (SNP) or NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) on the MTs organization in different root cells of Arabidopsis thaliana were tested. Subsequently, realization of the MT-mediated processes such as root growth and development was studied under these conditions. Arabidopsis thaliana seedlings expressing the chimeric gene gfp-map4 were exposed to the enhanced UV-B with or without SNP or c-PTIO pretreatment. The UV-B irradiation alone led to a dose-dependent root growth inhibition and to morphological alterations of the primary root manifested in their swelling and excessive root hair formation. Moreover, dose-dependent randomization and depolymerization of MTs in both epidermal and cortical cells under the enhanced UV-B were found. However, SNP pretreatment of the UV-B irradiated A. thaliana seedlings recovered the UV-B inhibited root growth as compared to c-PTIO pretreatment. It has been shown that in 24 h after UV-B irradiation the organization of MTs in root epidermal cells of SNP-pretreated A. thaliana seedlings was partially recovered, whereas in c-PTIO-pretreated ones the organization of MTs has not been distinctly improved. Therefore, we suppose that the enhanced NO levels in plant cells can protect MTs organization as well as MT-related processes of root growth and development against disrupting effects of UV-B.

Role and Interrelationship of Gα Protein, Hydrogen Peroxide, and Nitric Oxide in Ultraviolet B-Induced Stomatal Closure in Arabidopsis Leaves

“…The structure and dynamics of cytoskeleton, the main cellular players in stomatal movement (Huang et al, 2009;Eisinger et al, 2012aEisinger et al, , 2012b) that can control ion channels in guard cells (Zhang et al, 2007), have been shown to be regulated by NO as well as H 2 O 2 (Huang et al, 2009;Wilkins et al, 2011;Yemets et al, 2011). Recent evidence also suggests that NO mediates UV-B signaling in plant cells by modulating cytoskeleton (Yemets et al, 2011;Krasylenko et al, 2012). Thus, whether the UV-B-dependent NO induces stomatal closure via modulating cytoskeleton and the subsequent activation of ion channels is an interesting question to be addressed in the future.…”

Plant microtubules reorganization under the indirect UV-B exposure and during UV-B-induced programmed cell death

“…[21][22][23][24][25] It was shown recently that the interphase and mitotic MTs in epidermal and cortex cells of all primary root zones of Arabidopsis thaliana L. seedlings expressing gfp-map4 (microtubule-assosiated protein 4) were randomized, depolymerized and/or stabilized in dose-dependent manner after the UV-B exposure (13.6-68 kJ/m 2 ) in vivo that was accompanied by the cell swelling and excessive root hairs formation. 26 Our further experiments give additional evidences that plant MTs are involved in signal transduction under UV-B stress. The experimental system based on A. thaliana (GFP-MAP4) 4 d-old seedlings having their primary roots protected with aluminum foil downwards from the hypocotyls (hereinafter referred to as shielded seedlings) to avoid the direct UV-B exposure were designed.…”

“…32 We have shown also that immediately after the UV-B exposure (13.6-68 kJ/m 2 ) cortical MTs in both transition and elongation zones depolymerized rapidly. 26 Furthermore, UV-B-induced MTs reorganization in root cells of shielded A. thaliana seedlings was accompanied by primary root growth inhibition (Fig. 1II, 27.2 kJ/m 2 UV-B, shielded roots, 68 kJ/m 2 UV-B, shielded roots, respectively) and epidermal cells swelling together with the intense root hairs formation in differentiation zone (Fig.…”

Functional Role of Nitric Oxide Under Abiotic Stress Conditions

“…It was also indicated that NO is involved in secondary metabolite production. Recently, it was suggested that UV-B-enhanced NO levels in plant cells can also protect microtubule organization as well as microtubule-related processes of root growth and development against disrupting effects of UV-B (Krasylenko et al 2012). …”