Mdivi-1 Induced Mitochondrial Fusion as a Potential Mechanism to Enhance Stress Tolerance in Wheat

Abstract

Mitochondria play a key role in providing energy to cells. These organelles are constantly undergoing dynamic processes of fusion and fission that change in stressful conditions. The role of mitochondrial fusion in wheat root cells was studied using Mdivi-1, an inhibitor of the mitochondrial fragmentation protein Drp1. The effect of the inhibitor was studied on mitochondrial dynamics in the roots of wheat seedlings subjected to a wounding stress, simulated by excision. Treatment of the stressed roots with the inhibitor increased the size of the mitochondria, enhanced their functional activity, and elevated their membrane potentials. Mitochondrial fusion was accompanied by a decrease in ROS formation and associated cell damage. Exposure to Mdivi-1 also upregulated genes encoding the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and an energy sensor AMP-dependent protein sucrose non-fermenting-related kinase (SnRK1), suggesting that mitochondrial fusion is associated with a general activation of energy metabolism. Controlling mitochondrial fusion rates could change the physiology of wheat plants by altering the energy status of the cell and helping to mitigate the effects of stress.

Nitric Oxide Induces Autophagy in Triticum aestivum Roots

“…The assessment of cell viability was performed by staining dead cells with propidium iodide (1 μM PI, Sigma, λ ab 485 nm/λ em 610 nm) [ 19 ]. The mitochondrial membrane potential was assessed using the voltage-dependent fluorescent dye tetramethylrhodamine methyl ester (1 μM TMRM, Sigma, Shanghai, China, λ ab 543 nm/λ e m 573 nm), which accumulates in the matrix of energized mitochondria [ 20 ]. Fluorescence images were visualized using a confocal microscope LSM-510 META (Carl Zeis, Jena, Germany).…”

“…Membrane permeability was evaluated by the leakage of electrolytes from roots using a conductivity meter, Cond 7310 (WTW, Weilheim, Germany), and the index of membrane stability (IMS) was calculated as a percentage of the total yield of electrolytes [ 20 ].…”

“…Roots (150 mg) were immersed in the corresponding solutions (3 mL) in Warburg vials. Respiration rates were measured during 3 h [ 20 ].…”

“…For transmission electron microscopy, the intact roots from 10–15 randomly chosen wheat seedlings were incubated by gentle shaking in working solutions for 3 h. Root slices 1–2 mm thick from the root elongation zone were initially fixed with a 2.5% glutaraldehyde solution (1.5 h) and then post-fixed with 1% osmium tetroxide in 0.1 M Na phosphate buffer, pH 7.4, for 2 h, and then the samples were processed as described previously [ 20 ]. The preparations were examined using a transmission electron microscope, Jem-1200 EX (Jeol Ltd., Akishima, Japan).…”