scholarly journals MNB1 gene is involved in regulating the iron-deficiency stress response in Arabidopsis thaliana

Author(s):  
Hui Song ◽  
Feng Chen ◽  
Xi Wu ◽  
Min Hu ◽  
Qingliu Geng ◽  
...  

Abstract Abstract Iron (Fe) is an indispensable mineral element for normal growth of plants. Fe deficiency induces a complex series of responses in plants, involving physiological and developmental changes, to increase Fe uptake from soil. However, the molecular mechanism involved in plant Fe-deficiency is not well understood. Here, we found that the MNB1 gene is involved in modulating Fe-deficiency response in Arabidopsis thaliana . The expression of MNB1 was inhabited by Fe-deficiency stress. Knockout of MNB1 led to enhanced Fe accumulation and tolerance, whereas the MNB1-overexpressing plants were sensitive to Fe-deficiency stress. Lower H 2 O 2 concentrations in mnb1 mutant plants were examined under Fe deficiency circumstances compared to wild-type. On the contray, higher H 2 O 2 concentrations were found in MNB1-overexpressing plants, which was adversely linked with malondialdehyde (MDA) concentrations. Furthermore, in mnb1 mutants, the transcription level of the Fe-uptake and translocation genes, FIT , IRT1 , FRO2 , Z IF , FRD3 , NAS4 , PYE and MYB72 , were considerably elevated during Fe-deficiency stress, resulting in higher Fe accumulation. Together, our findings show that the MNB1 gene negatively controls the Fe-deficiency response in Arabidopsis via modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling pathway, thereby affecting the expression of Fe-uptake and translocation genes.

2016 ◽  
Vol 43 (3) ◽  
pp. 221 ◽  
Author(s):  
Min Yan ◽  
Wen Jing ◽  
Ni Xu ◽  
Like Shen ◽  
Qun Zhang ◽  
...  

Reactive oxygen species (ROS) play a key signalling role in cells. Plant NADPH oxidases, also known as respiratory burst oxidase homologues (Rbohs), are well characterised ROS-generating systems. In this study, we found that the constitutively active small guanosine triphosphatase (GTPase) ROP11 (CA-ROP11) interacted with RbohF by using a yeast two-hybrid analysis, a pull-down assay and an in vivo bimolecular fluorescence complementation assay. The mutation of amino acid L336 or L337 in RbohF abolished its interaction with CA-ROP11. Coexpression of CA-ROP11 and wild-type RbohF in Nicotiana benthamiana Domin enhanced ROS production compared with coexpression of CA-ROP11 and mutant RbohF or of dominant negative ROP11 and wild-type RbohF. Moreover, CA-ROP11 overexpression resulted in ROS accumulation and a swollen root hair phenotype in Arabidopsis thaliana (L.) Heynh. The deletion of RbohF partially reduced the increase in ROS in Arabidopsis plants overexpressing CA-ROP11. These results suggest that Arabidopsis ROP11 modulates ROS production by interacting with RbohF in root hairs.


2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Anne-Cécile Ribou ◽  
Klaus Reinhardt

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Christopher S Wilcox ◽  
Cheng Wang ◽  
Dan Wang

Background: Angiotensin II (Ang II) increases reactive oxygen species (ROS) and contractions to thromboxane and endothelin-1 (ET-1). Therefore, we tested the hypothesis that cyclooxygenase (COX) and/or thromboxane-prostanoid receptors (TP-Rs) mediate enhanced ROS generations with ET-1 in Ang II-infused mice. Methods: ROS was assessed by urinary 8-isoprotane(8-Iso) excretion and ethedium : dihydroetheldium (DHE) in mesenteric resistance arterioles (MRAs) from wild type (+/+) and littermate COX-1 -/- or TP-R -/- mice infused with vehicle or angiotensin II (Ang II, 400 ng/kg/min for 14 days) (n=6/ group, mean ±SEM). Results: Ang II infusion increased excretion (ng/mg creatine) of TxB 2 (1.3±0.1±1.0±0.1 in COX-1 +/+ mice and 1.9±0.1 vs 1.2±0.1 in TP-R +/+ mice, all P<0.05) and 8-Iso (2.1±0.2 vs 1.4±0.1 in COX-1 +/+ mice and 2.2±0.1 vs 1.4±0.2 in TP-R +/+ mice, all P<0.05) but not in COX-1 -/- or TP-R -/- mice. Ang II enhanced ROS generation (Δunit) with 10 -7 M ET-1 in MRAs from both +/+ mouse genotypes (1.7±0.2 vs 0.1±0.1 in COX-1 +/+ mice and 3.2±0.3 vs 0.1±0.1 in TP-R +/+ mice, all P<0.01). However, this increase in ROS was fully prevented in TP-R-/- mouse vessels (0.3±0.2 vs 0.2±0.1, NS) and in COX-1 +/+ mouse vessels after combined blockade of COX-1( 10 -5 M SC-560) and -2 (paracoxib 10 -5 M) (0.2±0.1 vs 0.1±0.1, NS) and in COX-1 -/- mouse vessels after paracoxib (0.2±0.1 vs 0.2±0.2, NS). Increased ROS generation was only partially prevented in COX-1 -/- mouse vessels (0.5±0.1 vs 0.2±0.2, P<0.05) or in COX-1 +/+ mouse vessels after blockade of COX-1 ( 0.7±0.1 vs 0.1±0.1, NS) or COX-2 (1.0±0.1 vs 0.1±0.1,P<0.05). Conclusions: Increased ROS generation with ET-1 in microvessels from Ang II infused mice depends on products of both COX-1 and -2 that activate TP-Rs. Thus, combined blockade of COX-1 and -2 or TP-Rs may prevent vascular ROS and its many complications during increased Ang II and ET-1, such as hypertension, hypoxia or shock.


Author(s):  
Minu Kesheri ◽  
Swarna Kanchan ◽  
Rajeshwar P. Sinha

In retrospect to the rise in the occurrence of ageing related disorders and the everlasting desire to overcome ageing, exploring the causes, mechanisms and therapies to curb ageing becomes relevant. Reactive Oxygen Species (ROS) are commonly generated during normal growth and development. However abiotic and biotic stresses enhance the level of ROS which in turn pose the threat of oxidative stress. Ability to perceive ROS and to speedily commence antioxidant defenses is crucial for the survival as well as longevity of living cells. Therefore living organisms are bestowed with antioxidants to combat the damages caused by oxidative stress. This chapter aims to elucidate an overview of the process of ageing, generation and enhancement of reactive oxygen species, damages incurred by oxidative stress, its amelioration strategies, therapeutic and biotechnological potentials of antioxidants and various sources of bioactive compounds significant in retardation of aging process.


2004 ◽  
Vol 286 (5) ◽  
pp. C1152-C1158 ◽  
Author(s):  
A. McArdle ◽  
J. van der Meulen ◽  
G. L. Close ◽  
D. Pattwell ◽  
H. Van Remmen ◽  
...  

Contractions of skeletal muscles produce increases in concentrations of superoxide anions and activity of hydroxyl radicals in the extracellular space. The sources of these reactive oxygen species are not clear. We tested the hypothesis that, after a demanding isometric contraction protocol, the major source of superoxide and hydroxyl radical activity in the extracellular space of muscles is mitochondrial generation of superoxide anions and that, with a reduction in MnSOD activity, concentration of superoxide anions in the extracellular space is unchanged but concentration of hydroxyl radicals is decreased. For gastrocnemius muscles from adult (6–8 mo old) wild-type ( Sod2+/+) mice and knockout mice heterozygous for the MnSOD gene ( Sod2+/-), concentrations of superoxide anions and hydroxyl radical activity were measured in the extracellular space by microdialysis. A 15-min protocol of 180 isometric contractions induced a rapid, equivalent increase in reduction of cytochrome c as an index of superoxide anion concentrations in the extracellular space of Sod2+/+ and Sod2+/- mice, whereas hydroxyl radical activity measured by formation of 2,3-dihydroxybenzoate from salicylate increased only in the extracellular space of muscles of Sod2+/+ mice. The lack of a difference in increase in superoxide anion concentration in the extracellular space of Sod2+/+ and Sod2+/- mice after the contraction protocol supported the hypothesis that superoxide anions were not directly derived from mitochondria. In contrast, the data obtained suggest that the increase in hydroxyl radical concentration in the extracellular space of muscles from wild-type mice after the contraction protocol most likely results from degradation of hydrogen peroxide generated by MnSOD activity.


2011 ◽  
Vol 168 (5) ◽  
pp. 434-440 ◽  
Author(s):  
Lung-Jiun Shin ◽  
Hsiang-En Huang ◽  
Hsiang Chang ◽  
Yi-Hsien Lin ◽  
Teng-Yung Feng ◽  
...  

2009 ◽  
Vol 22 (7) ◽  
pp. 868-881 ◽  
Author(s):  
Jeannine Lherminier ◽  
Taline Elmayan ◽  
Jérôme Fromentin ◽  
Khadija Tantaoui Elaraqui ◽  
Simona Vesa ◽  
...  

Chemiluminescence detection of reactive oxygen species (ROS) triggered in tobacco BY-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane NADPH oxidase, NtrbohD. Here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and NtrbohD mediated. Furthermore, the presence of NtrbohD in detergent-resistant membrane fractions could be associated with the presence of NtrbohD-mediated hydrogen peroxide patches along the plasma membrane. Comparison of the subcellular localization of ROS in wild-type tobacco and in plants transformed with antisense constructs of NtrbohD revealed that this enzyme is also responsible for the hydrogen peroxide production occurring at the plasma membrane after infiltration of tobacco leaves with cryptogein. Finally, the reactivity of wild-type and transformed plants to the elicitor and their resistance against the pathogenic oomycete Phytophthora parasitica were examined. NtrbohD-mediated hydrogen peroxide production does not seem determinant for either hypersensitive response development or the establishment of acquired resistance but it is most likely involved in the signaling pathways associated with the protection of the plant cell.


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