Biochemical and molecular approach of oxidative damage triggered by water stress and rewatering in sunflower seedlings of two inbred lines with different ability to tolerate water stress

2020 ◽  
Vol 47 (8) ◽  
pp. 727
Author(s):  
Federico Ramírez ◽  
Maximiliano Escalante ◽  
Ana Vigliocco ◽  
M. Verónica Pérez-Chaca ◽  
Mariana Reginato ◽  
...  

Water stress accelerates the generation of reactive oxygen species, which trigger a cascade of antioxidative defence mechanisms comprising enzymatic and nonenzymatic antioxidants. The aim of this study was to investigate the oxidative damage and the antioxidative defence systems in seedlings of the water stress-tolerant (B71) and the sensitive (B59) inbred lines of sunflower (Helianthus annuus L.) in response to water stress and rewatering. In addition, we characterised the transcriptomic profile associated with enzymatic antioxidative defence. An elevated electrolyte leakage in B59 indicated increased plasmatic membrane permeability, which correlated with greater sensitivity to water stress. In response to water stress, both lines showed an increase in malondialdehyde and H2O2 content but these increases were more noticeable in the sensitive line. In both lines, an increase in enzymatic activity (e.g. peroxidase and ascorbate peroxidase) was not sufficient to overcome the H2O2 accumulation triggered by water stress. Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71 and decreased in B59, which showed downregulated levels of most genes in the shoots. The general profile of phenolic compounds was clearly different between organs and between inbred lines. The B59 line activated nonenzymatic antioxidant responses to counteract the oxidative stress caused by water stress. The tolerance of B71 to water stress could be associated with compensatory antioxidant mechanisms based on the expression of genes encoding enzyme components of the ascorbate–glutathione and redoxin cycles, which contributed to explaining, at least partly, the response of this line.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zheng Chen ◽  
Jiayang Xu ◽  
Fazhan Wang ◽  
Lin Wang ◽  
Zicheng Xu

AbstractTo gain insight into the molecular mechanisms underpinning tobacco (Nicotiana tabacum) tolerance to drought stress, we integrated anatomical, physiological, and proteomic analyses of drought-tolerant (Yuyan6, [Y6]) and -sensitive (Yunyan87 [Y87]) varieties. In comparison to Y87, Y6 exhibited higher water retention capability, improved photosynthetic performance, delayed leaf-senescence, stable leaf ultrastructure, a stronger antioxidant defense, and lesser ROS accumulation when subjected to water stress. Using an iTRAQ-based proteomics approach, 405 and 1,560 differentially accumulated proteins (DAPs) were identified from Y6 and Y87 plants, respectively, of which 114 were found to be present in both cultivars. A subsequent functional characterization analysis revealed that these DAPs were significantly enriched in eight biological processes, six molecular functions, and six cellular components and displayed differential expression patterns in Y6 and Y87 plants, suggesting that the response to water stress between both varieties differed at the proteomic level. Furthermore, we constructed protein coexpression networks and identified hub proteins regulating tobacco defenses to water stress. Additionally, qPCR analysis indicated that the majority of genes encoding selected proteins showed consistency between mRNA levels and their corresponding protein expression levels. Our results provide new insights into the genetic regulatory mechanisms associated with drought response in tobacco plants.


2014 ◽  
Vol 69 (7-8) ◽  
pp. 300-308 ◽  
Author(s):  
Xin Sun ◽  
Cui-Qin Yang ◽  
Tao Wen ◽  
Fu-Chun Zeng ◽  
Qiang Wang ◽  
...  

Plastid terminal oxidase (PTOX) is a plastid-localized plastoquinone (PQ) oxidase in plants. It functions as the terminal oxidase of chlororespiration, and has the potential ability to regulate the redox state of the PQ pool. Expression of the PTOX gene was up-regulated in soybean seedlings after exposure to water deficit stress for 6 h. Concomitantly expression of the NDH-H gene, encoding a component of the NADPH dehydrogenase (NDH) complex which is a key component of both chlororespiration and NDH-dependent cyclic electron transfer (CET), was also up-regulated. Transcript levels of the proton gradient regulation (PGR5) gene, which encodes an essential component of the PGR5-dependent CET, were not affected by water stress, while the expression of the alternative oxidase (AOX1) gene, which encodes a terminal oxidase of alternative respiration in mitochondria, was also up-regulated under water stress. Therefore, our results indicate that water stress induced the up-regulation of genes encoding key components of chlororespiration and alternative respiration. Transcript levels of the AOX1 gene began to increase in response to water stress before those of PTOX suggesting that alternative respiration may react faster to water stress than chlororespiration.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Cai-Xia Liu ◽  
Ying-Zi Tan ◽  
Chang-Qing Deng

To explore the main active components and effects of cell cycle regulation mechanism of Astragali radix (AR) and Angelicae sinensis radix (ASR) on oxidative damage in vascular endothelial cells, a model of oxidative damage in human umbilical vein endothelial cells (HUVECs) induced by oxidized low-density lipoprotein (ox-LDL) treatment was developed. Based on the “knock-out/knock-in” model of the target component, cell viability, intracellular reactive oxygen species (ROS), and lactate dehydrogenase (LDH) leakage were assessed by Cell Counting Kit-8 assay, fluorescent probe 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA), and colorimetric assay, respectively, to evaluate the protective effect of the active components of AR and ASR (astragaloside IV (AS IV), astragaloside I (AS I), formononetin (FRM), calycosin (CAL), calycosin-7-O-β-D glucoside (CLG), and ferulic acid (FRA)) against oxidative damage. The cell cycle and expression of genes encoding cyclins and cyclin-dependent kinases (CDKs) were observed using flow cytometry and quantitative real-time polymerase chain reaction. The results showed that the combination of active components (ACC) significantly inhibited the decrease in cell viability as well as the increase in ROS and LDH release in HUVECs induced by ox-LDL treatment. AS IV and FRM promoted the proliferation of HUVECs but the proliferation index was decreased in the AS I and FRA groups; this inhibitory effect was counteracted by the ACC. The ACC reduced and increased the proportion of positive cells in G1 and S phases, respectively, followed by the upregulation of cyclin A (CCNA), cyclin E (CCNE), and CDK2 mRNA expression and downregulation of cyclin B (CCNB), cyclin D1 (CCND1), CDK1, CDK4, and CDK6 mRNA expression, which significantly mitigated inhibition of HUVECs proliferation induced by ox-LDL treatment. Taken together, AS IV, AS I, FRM, CAL, CLG, and FRA were the primary pharmacodynamic substances of AR and ASR that alleviated oxidative injury in HUVECs. ACC mitigated the upregulation of intracellular ROS levels and LDH release induced by ox-LDL treatment, which promoted the cell cycle procession of HUVECs by regulating the expression of genes encoding cyclins and CDKs and thus preventing oxidative damage in HUVECs.


Crop Science ◽  
2011 ◽  
Vol 51 (1) ◽  
pp. 157-172 ◽  
Author(s):  
Kristen A. Leach ◽  
Lindsey G. Hejlek ◽  
Leonard B. Hearne ◽  
Henry T. Nguyen ◽  
Robert E. Sharp ◽  
...  

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