Alternative oxidase pathway is involved in the exogenous SNP-elevated tolerance of Medicago truncatula to salt stress

Ji, Wei; Zhang, Dawei; Feng, Zhaozhong; Wang, Shuo-xun; Pu, Xiaojun; Deng, Xing-Guang; Luo, Shi-Shuai; Lin, Honghui

doi:10.1016/j.jplph.2016.01.018

Cited by 41 publications

(36 citation statements)

References 45 publications

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“…5e). Plant signaling molecules, such as nitric oxide, can regulate the alternative respiratory pathway in stress conditions44. Whether an H 2 S signal or Cys could affect AP activity was not previously known; our analysis found that exogenous H 2 S or Cys supplementation could further induce the activity of AP in Cd 2+ stress.…”

Section: Discussionmentioning

confidence: 62%

Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots

Jia

Wang

Dou

et al. 2016

Sci Rep

108

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Cadmium (Cd 2+ ) is a common toxic heavy metal ion. We investigated the roles of hydrogen sulfide (H 2 S) and cysteine (Cys) in plant responses to Cd 2+ stress. The expression of H 2 S synthetic genes LCD and DES1 were induced by Cd 2+ within 3 h, and endogenous H 2 S was then rapidly released. H 2 S promoted the expression of Cys synthesis-related genes SAT1 and OASA1, which led to endogenous Cys accumulation. The H 2 S and Cys cycle system was stimulated by Cd 2+ stress, and it maintained high levels in plant cells. H 2 S inhibited the ROS burst by inducing alternative respiration capacity (AP) and antioxidase activity. H 2 S weakened Cd 2+ toxicity by inducing the metallothionein (MTs) genes expression. Cys promoted GSH accumulation and inhibited the ROS burst, and GSH induced the expression of phytochelatin (PCs) genes, counteracting Cd 2+ toxicity. In summary, the H 2 S and Cys cycle system played a key role in plant responses to Cd 2+ stress. The Cd 2+ tolerance was weakened when the cycle system was blocked in lcddes1-1 and oasa1 mutants. This paper is the first to describe the role of the H 2 S and Cys cycle system in Cd 2+ stress and to explore the relevant and specificity mechanisms of H 2 S and Cys in mediating Cd 2+ stress.Cadmium (Cd 2+ ) is a common toxic heavy metal ion in the environment. It greatly affects the growth and development of plants and is harmful to human health through the food chain 1,2 . Because of its carcinogenic properties and its detrimental effects on the growth of organisms, Cd 2+ contamination of agricultural soil has become a critical concern. Preventing reduced growth and accumulation of Cd 2+ in harvested organs of plants growing on Cd 2+ -contaminated soils has become an urgent task as it can contribute to food safety. Thus, it is important to explore plant stress defense mechanisms and to find ways to reduce the Cd 2+ accumulation in grains.As a heavy metal not participating in redox reactions, Cd 2+ can easily dissolve in water and quickly be taken up by plant roots 3,4 . The physiological consequences of Cd 2+ toxicity in plants are chlorosis, stunted growth, and cell death, among others [5][6][7] . At the cellular level, Cd 2+ can alter protein structure and inhibit enzyme activity by binding to sulfhydryl and carbonyl groups and replacing essential co-factors of enzymes [7][8][9] . The overproduction of reactive oxygen species (ROS) is the primary response of plants to Cd 2+ with negative impact on cell function 10 . Further damage can be caused by ROS-independent, secondary mechanisms. Lipid peroxidation is the most deleterious effect caused by Cd 2+ -induced ROS 4 . Malondialdehyde (MDA), one of the decomposition products of lipid peroxidation, can modify active substrates in plant cells, including nucleic acids, proteins and saccharides 11 . To become resistant to Cd 2+ toxicity, plants have developed several strategies, such as inducing the

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Section: Discussionmentioning

confidence: 62%

Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots

Jia

Wang

Dou

et al. 2016

Sci Rep

108

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“…In this study, we found that endogenous CA (RNAi-aco strains) and exogenous CA induced aox gene expression under heat stress. A large amount of evidence has suggested that the enhanced alternative pathway improved stress tolerance by maintaining redox homeostasis in the plants (21,47). In fungi, AOX is involved in stress defense mechanisms or in metabolism regulation.…”

Section: Discussionmentioning

confidence: 99%

Nitric Oxide Improves the Tolerance of Pleurotus ostreatus to Heat Stress by Inhibiting Mitochondrial Aconitase

Hou

Zhao

Huang

et al. 2020

Appl Environ Microbiol

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Pleurotus ostreatus is widely cultivated in China. However, its cultivation is strongly affected by seasonal temperature changes, especially the high temperatures of summer. Nitric oxide (NO) was previously reported to alleviate oxidative damage to mycelia by regulating trehalose. In this study, we found that NO alleviated oxidative damage to P. ostreatus mycelia by inhibiting the protein and gene expression of aconitase (ACO), and additional studies found that the overexpression and interference of aco could affect the content of citric acid (CA). Furthermore, the addition of exogenous CA can induce alternative oxidase (aox) gene expression under heat stress, reduce the content of H 2 O 2 in mycelium, and consequently protect the mycelia under heat stress. An additional analysis focused on the function of the aox gene in the heat stress response of mycelia. The results show that the colony diameter of the aox overexpression (OE-aox) strains was significantly larger than that of the wild-type (WT) strain under heat stress (32°C). In addition, the mycelia of OEaox strains showed significantly enhanced tolerance to H 2 O 2 . In conclusion, this study demonstrates that NO can affect CA accumulation by regulating aco gene and ACO protein expression and that CA can induce aox gene expression and thereby be a response to heat stress. IMPORTANCE Heat stress is one of the abiotic stresses that affect the growth and development of edible fungi. Our previous study found that exogenous NO had a protective effect on mycelia under heat stress. However, its regulatory mechanism had not been elucidated. In this study, we found that NO altered the respiratory pathway of mycelia under heat stress by regulating aco. The results have enhanced our understanding of NO signaling pathways in P. ostreatus.

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“…3 ROS and RNS plays a major role in developmental as well as abiotic and biotic stress signaling in plants attributed to the regulatory mechanisms controlling their production. 26 …”

Section: Aox and Retrograde Signalingmentioning

confidence: 99%

Alternative oxidase and plant stress tolerance

Saha

Боровский

Panda

2016

Plant Signaling & Behavior

137

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Alternative oxidase (AOX) is one of the terminal oxidases of the plant mitochondrial electron transport chain. AOX acts as a means to relax the highly coupled and tensed electron transport process in mitochondria thus providing and maintaining the much needed metabolic homeostasis by directly reducing oxygen to water. In the process AOX also act as facilitator for signaling molecules conveying the metabolic status of mitochondria to the nucleus and thus able to influence nuclear gene expression. Since AOX indirectly, is able to control the synthesis of important signaling molecules like hydrogen peroxide, superoxide, nitric oxide, thus it is also helping in stress signaling. AOX mediated signaling and metabolic activities are very much important for plant stress response. This include both biotic (fungal, bacterial, viral, etc.) and abiotic (drought, salinity, cold, heavy metal, etc.) stresses. The review provides a gist of regulation and functioning of AOX. Plants being sessile, are exposed to various environmental stressors, viz, drought, salinity, metal toxicity, low or high temperature, pathogen attack, nutrient deficiency, hypoxia etc; which aims to hamper their lifestyle and lifespan to a great extent. So, it has developed certain inbuilt mechanism for perception of minute changes in the environment and responders which facilitates, either tolerance or avoidance responses to alleviate the stress. This review rotates round one of these molecules which helps in stress perception and mediates a retrograde signaling pathway to architect a tolerance/avoidance response. What is Alternative Oxidase?The discovery of alternative oxidase (AOX) was at the beginning of the 20 th century from thermogenic plants during anthesis. AOXs are interfacial membrane bound, cyanide insensitive, metallo-protein involved in mitochondrial redox reactions. AOX branches off from the cytochrome pathway of mitochondria at the level of Ubiquinone (UQ) and is responsible for coupling, oxidation of ubiquinol, to 4 electron reduction of oxygen to water.1 As AOX bypasses Complex III and IV of the cytochrome pathway, it dramatically reduces ATP generation and the energy thus released is dissipated as heat.2 It helps in maintaining metabolic homeostasis and signaling dynamics in mitochondria. Stressors effect plant growth resulting in misbalance of energy demands and production. The ability of plants to maintain the delicate balance of energy production and utilization is fundamentally important for their survival. Presence of AOX forms the striking functional difference between mitochondria of higher plants (as well as some fungi and protists) and animals, i.e., presence of two terminal oxidases, AOX and cytochrome oxidase. AOX is encoded by two nuclear gene subfamily, AOX1 and AOX2, where dicotyledons possesses both gene ubfamilies, while monocots have only AOX1 genes.3 AOX is responsible for thermogenesis (attract insects for pollination) and stress tolerance. In response to stress AOX mediates a retrograde signaling pathway which...

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Alternative oxidase pathway is involved in the exogenous SNP-elevated tolerance of Medicago truncatula to salt stress

Cited by 41 publications

References 45 publications

Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots

Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots

Nitric Oxide Improves the Tolerance of Pleurotus ostreatus to Heat Stress by Inhibiting Mitochondrial Aconitase

Alternative oxidase and plant stress tolerance

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