Programmed Cell Death in Plants: Protective Effect of Tetraphenylphosphonium and Tetramethylrhodamine Cations Used as Transmembrane Quinone Carriers

---

L. A. Vasil’ev, D. B. Kiselevsky, E. V. Dzyubinskaya, A. V. Nesov, and V. D. Samuilov^*

Department of Immunology, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-3807; E-mail: vdsamuilov@mail.ru

^* To whom correspondence should be addressed.

Received November 22, 2011; Revision received December 22, 2011

---

Tetraphenylphosphonium (TPP⁺) and tetramethylrhodamine ethyl ester (TMRE⁺) cations used as transmembrane carriers of ubiquinone (MitoQ) and plastoquinone (SkQ, SkQR) in mitochondria prevented at nanomolar concentrations the chitosan- or H₂O₂-induced destruction of the nucleus in epidermal cells of epidermis isolated from pea leaves. The protective effect of the cations was potentiated by palmitate. Penetrating anions of tetraphenylboron (TB^–) and phenyl dicarbaundecaborane also displayed protective effects at micromolar concentrations; the effect of TB^– was potentiated by NH₄Cl. It is proposed that the protective effect of the penetrating cations and anions against chitosan is due to suppression of the generation of reactive oxygen species in mitochondria as a result of the protonophoric effect of the cations plus fatty acids and the anions plus NH₄⁺. Phenol was suitable as the electron donor for H₂O₂ reduction catalyzed by horseradish peroxidase, preventing the destruction of cell nuclei. The penetrating cations and anions, SkQ1, and SkQR1 did not maintain the peroxidase or peroxidase/oxidase reactions measured by their suitability as electron donors for H₂O₂ reduction or by the oxidation of exogenous NADH.

---

KEY WORDS: penetrating ions, tetraphenylphosphonium, tetramethylrhodamine ethyl ester, tetraphenylboron anion, phenyl dicarbaundecaborane anion, cell nucleus destruction, protective effect, plant epidermal cells, chitosan, CN^–

DOI: 10.1134/S0006297912040062

---