Disturbance of reactive oxygen species homeostasis induces atypical tubulin polymer formation and affects mitosis in root‐tip cells of Triticum turgidum and Arabidopsis thaliana

Abstract

In this study, the effects of disturbance of the reactive oxygen species (ROS) homeostasis on the organization of tubulin cytoskeleton in interphase and mitotic root-tip cells of Triticum turgidum and Arabidopsis thaliana were investigated. Reduced ROS levels were obtained by treatment with diphenylene iodonium (DPI) and N-acetyl-cysteine, whereas menadione was applied to achieve ROS overproduction. Both increased and low ROS levels induced: (a) Macrotubule formation in cells with low ROS levels and tubulin paracrystals under oxidative stress. The protein MAP65-1 was detected in treated cells, exhibiting a conformation comparable to that of the atypical tubulin polymers. (b) Disappearance of microtubules (MTs). (c) Inhibition of preprophase band formation. (d) Delay of the nuclear envelope breakdown at prometaphase. (e) Prevention of perinuclear tubulin polymer assembly in prophase cells. (f) Loss of bipolarity of prophase, metaphase and anaphase spindles. Interestingly, examination of the A. thaliana rhd2/At respiratory burst oxidase homolog C (rbohc) NADPH oxidase mutant, lacking RHD2/AtRBOHC, gave comparable results. Similarly to DPI, the decreased ROS levels in rhd2 root-tip cells, interfered with MT organization and induced macrotubule assembly. These data indicate, for first time in plants, that ROS are definitely implicated in: (a) mechanisms controlling the assembly/disassembly of interphase, preprophase and mitotic MT systems and (b) mitotic spindle function. The probable mechanisms, by which ROS affect these processes, are discussed.

Role of Reactive Oxygen Species during Cell Expansion in Leaves

“…Interestingly, microtubules and actin filaments are known to be very sensitive to ROS, and emerging evidence suggests that redox cues impact on cytoskeleton dynamics (Livanos et al, 2012). Chemical interference with ROS homeostasis results in the reorientation and replacement of MTs in plants.…”

“…ANPs are required during cytokinesis, but also regulate pavement cell expansion, since anp2anp3 mutants show aberrant epidermal cell morphology (Beck et al, 2010). Notably, downstream the MAPK cascade act two conserved key regulators of cortical MT array organization, the microtubule-associated proteins MAP65-1 and MAP65-2, which both have been implicated in ROS responses (Lucas et al, 2011;Zhu et al, 2013;Livanos et al, 2012). Potentially, H 2 O 2 sensed by the ANP cascade modulates cytoskeleton dynamics during cell proliferation and expansion (Fig.…”

oiwa, a Female Gametophytic Mutant Impaired in a Mitochondrial Manganese-Superoxide Dismutase, Reveals Crucial Roles for Reactive Oxygen Species during Embryo Sac Development and Fertilization in Arabidopsis

“…This defect may be due to the fact that intracellular ROS oscillations might regulate key components of the cell division machinery. ROS were reported to regulate Ca 2+ gradients and to participate in the regulation of proteins such as cyclin-dependent kinases, mitogen-activated proteins, and possibly aurora kinases and therefore to regulate cell cycle progression, microtubule organization, and cell plate formation (Livanos et al, 2012a(Livanos et al, , 2012b. The abnormal nuclei migration patterns observed in some oiwa embryo sacs may also account for the elevated concentration of ROS in mutant gametophytes, as ROS might also disturb microtubule organization or dynamics.…”

“…The abnormal nuclei migration patterns observed in some oiwa embryo sacs may also account for the elevated concentration of ROS in mutant gametophytes, as ROS might also disturb microtubule organization or dynamics. The formation of atypical tubulin paracrystals has been reported to occur under elevated ROS levels via mitogen-activated protein kinase activation and MAP65 phosphorylation (Livanos et al, 2012b).…”

Immunogold method evidences that kinesin and myosin bind to and couple microtubules and actin filaments in lipotubuloids of Ornithogalum umbellatum ovary epidermis

“…cell growth (Mucha et al 2011). Recently, formation of wide microtubules, ''macrotubules'' was found in plant cells under changing level of reactive oxygen species (ROS) which function as signaling molecules (Livanos et al 2012).…”