RESUMEN
Mitochondrial alternative oxidase is an important protein involved in maintaining cellular metabolic and energy balance, especially under stress conditions. AOX genes knockout is aimed at revealing the functions of AOX genes. Under unfavourable conditions, AOX-suppressed plants (mainly based on Arabidopsis AOX1a-knockout lines) usually experience strong oxidative stress. However, a compensation effect, which consists of the absence of AOX1a leading to an increase in defence response mechanisms, concomitant with a decrease in ROS content, has also been demonstrated. This review briefly describes the possible mechanisms underlying the compensation effect upon the suppression of AOX1a. Information about mitochondrial retrograde regulation of AOX is given. The importance of ROS and mitochondrial membrane potential in triggering the signal transmission from mitochondria in the absence of AOX or disturbance of mitochondrial electron transport chain functions is indicated. The few available data on the response of the cell to the absence of AOX at the level of changes in the hormonal balance and the reactions of chloroplasts are presented. The decrease in the relative amount of reduced ascorbate at stable ROS levels as a result of compensation in AOX1a-suppressed plants is proposed as a sign of stress development. Obtaining direct evidence on the mechanisms and signalling pathways involved in AOX modulation in the genome should facilitate a deeper understanding of the role of AOX in the integration of cellular signalling pathways.
Asunto(s)
Arabidopsis , Regulación de la Expresión Génica de las Plantas , Especies Reactivas de Oxígeno/metabolismo , Regulación hacia Arriba , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Proteínas de Plantas/metabolismo , Mitocondrias/metabolismo , Arabidopsis/metabolismoRESUMEN
Here, recent publications on the role of mitochondrial non-phosphorylating pathways (NPhPs) in the electron transport chain during the de-etiolation of wheat leaves are reviewed. Among NPhPs, the alternative oxidase (AOX) pathway is the most effective pathway in maintaining cellular redox and energy balance, especially under stress conditions, including light stress. AOX is considered to dissipate excess reductants produced in the chloroplasts, and thereby prevent photooxidation. However, when etiolated wheat plants were exposed to a physiologically relevant light level, AOX was rapidly induced and increased, although the etioplasts did not produce excess reductants and have their own strong photoprotective mechanisms. The present study provides further insights into the role of AOX in greening cells and highlights the importance of AOX in the integration of cellular signalling pathways.
Asunto(s)
Homeostasis , Proteínas Mitocondriales , Oxidorreductasas , Hojas de la Planta , Proteínas de Plantas , Plantas , Transporte de Electrón , Proteínas Mitocondriales/metabolismo , Oxidorreductasas/metabolismo , Hojas de la Planta/enzimología , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Plantas/enzimologíaRESUMEN
Applicability of a new substrate for crops cultivation in bioregenerative LSSs with a high degree of mass-exchange closure was tested. Optimization of leaf cabbage nutrition by supplementing the basic substrate fabricated of plant and animal residues with ion-exchange resins proved to have a success.