scholarly journals NADPH Oxidase Is Crucial for the Cellular Redox Homeostasis in Fungal Pathogen Botrytis cinerea

2019 ◽  
Vol 32 (11) ◽  
pp. 1508-1516
Author(s):  
Hua Li ◽  
Shiping Tian ◽  
Guozheng Qin

During interactions, both plants and pathogens produce reactive oxygen species (ROS). Plants generate ROS for defense induction, while pathogens synthesize ROS for growth, sporulation, and virulence. NADPH oxidase (NOX) complex in the plasma membrane represents a main protein complex for ROS production in pathogens. Although NOX plays a crucial role in pathogenicity of pathogens, the underlying molecular mechanisms of NOX, especially the proteins regulated by NOX, remain largely unknown. Here, we applied an iodoacetyl tandem mass tag-based redox proteomic assay to investigate the protein redox dynamics in deletion mutant of bcnoxR, which encodes a regulatory subunit of NOX in the fungal pathogen Botrytis cinerea. In total, 214 unique peptidyl cysteine (Cys) thiols from 168 proteins were identified and quantified in both the wild type and ∆bcnoxR mutant. The Cys thiols in the ∆bcnoxR mutant were generally more oxidized than those in the wild type, suggesting that BcNoxR is essential for maintaining the equilibrium of the redox state in B. cinerea. Site-specific thiol oxidation analysis indicated that 142 peptides containing the oxidized thiols changed abundance significantly in the ∆bcnoxR mutant. Proteins containing these differential peptides are classified into various functional categories. Functional analysis revealed that one of these proteins, 6-phosphate dehydrogenase, played roles in oxidative stress response and pathogenesis of B. cinerea. These results provide insight into the potential target proteins and the ROS signal transduction pathway regulated by NOX.

2016 ◽  
Vol 29 (12) ◽  
pp. 990-1003 ◽  
Author(s):  
Hua Li ◽  
Zhanquan Zhang ◽  
Chang He ◽  
Guozheng Qin ◽  
Shiping Tian

The NADPH oxidase (NOX) complex has been shown to play a crucial role in stress response and in the virulence of various fungal pathogens. The underlying molecular mechanisms of NOX, however, remain largely unknown. In the present study, a comparative proteomic analysis compared changes in protein abundance in wild-type Botrytis cinerea and ΔbcnoxR mutants in which the regulatory subunit of NOX was deleted. The ΔbcnoxR mutants exhibited reduced growth, sporulation, and impaired virulence. A total of 60 proteins, representing 49 individual genes, were identified in ΔbcnoxR mutants that exhibited significant differences in abundance relative to wild-type. Reverse transcription-quantitative polymerase chain reaction analysis demonstrated that the differences in transcript levels for 36 of the genes encoding the identified proteins were in agreement with the proteomic analysis, while the remainder exhibited reverse levels. Functional analysis of four proteins that decreased abundance in the ΔbcnoxR mutants indicated that 6-phosphogluconate dehydrogenase (BcPGD) played a role in the growth and sporulation of B. cinerea. The Δbcpgd mutants also displayed impaired virulence on various hosts, such as apple, strawberry, and tomato fruit. These results suggest that NOX can influence the expression of BcPGD, which has an impact on growth, sporulation, and virulence of B. cinerea.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 565-577
Author(s):  
Daniel B Szymanski ◽  
Daniel A Klis ◽  
John C Larkin ◽  
M David Marks

Abstract In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUS1 (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S::GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S::GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, try, and 35S::GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.


2018 ◽  
Vol 315 (4) ◽  
pp. C494-C501 ◽  
Author(s):  
Wenli Liu ◽  
Yueqin Liu ◽  
Hongzhen Li ◽  
Griffin P. Rodgers

Neutrophils increase production of reactive oxygen species, including superoxide, hydrogen peroxide (H2O2), and hydroxyl radical, to destroy invading microorganisms under pathological conditions. Conversely, oxidative stress conditions, such as the presence of H2O2, induce neutrophil apoptosis, which helps to remove neutrophils after inflammation. However, the detailed molecular mechanisms that are involved in the latter process have not been elucidated. In this study, we investigated the potential role of olfactomedin 4 (Olfm4) in H2O2-induced superoxide production and apoptosis in mouse neutrophils. We have demonstrated that Olfm4 is not required for maximal-dosage PMA- and Escherichia coli bacteria-induced superoxide production, but Olfm4 contributes to suboptimal-dosage PMA- and H2O2-induced superoxide production. Using an NADPH oxidase inhibitor and gp91phox-deficient mouse neutrophils, we found that NAPDH oxidase was required for PMA-stimulated superoxide production and that Olfm4 mediated H2O2-induced superoxide production through NADPH oxidase, in mouse neutrophils. We have shown that neutrophils from Olfm4-deficient mice exhibited reduced H2O2-induced apoptosis compared with neutrophils from wild-type mice. We also demonstrated that neutrophils from Olfm4-deficient mice exhibited reduced H2O2-stimulated mitochondrial damage and membrane permeability, and as well as reduced caspase-3 and caspase-9 activity, compared with neutrophils from wild-type mice. Moreover, the cytoplasmic translocation of the proapoptotic mitochondrial proteins Omi/HtrA2 and Smac/DIABLO in response to H2O2was reduced in neutrophils from Olfm4-deficient mice compared with neutrophils from wild-type mice. Our study demonstrates that Olfm4 contributes to H2O2-induced NADPH oxidase activation and apoptosis in mouse neutrophils. Olfactomedin 4 might prove to be a potential target for future studies on inflammatory neutrophil biology and for inflammatory disease treatment.


2008 ◽  
Vol 21 (6) ◽  
pp. 808-819 ◽  
Author(s):  
Nadja Segmüller ◽  
Leonie Kokkelink ◽  
Sabine Giesbert ◽  
Daniela Odinius ◽  
Jan van Kan ◽  
...  

Nicotinamide adenine dinucleotide (NADPH) oxidases have been shown to be involved in various differentiation processes in fungi. We investigated the role of two NADPH oxidases in the necrotrophic phytopathogenic fungus, Botrytis cinerea. The genes bcnoxA and bcnoxB were cloned and characterized; their deduced amino acid sequences show high homology to fungal NADPH oxidases. Analyses of single and double knock-out mutants of both NADPH oxidase genes showed that both bcnoxA and bcnoxB are involved in formation of sclerotia. Both genes have a great impact on pathogenicity: whereas bcnoxB mutants showed a retarded formation of primary lesions, probably due to an impaired formation of penetration structures, bcnoxA mutants were able to penetrate host tissue in the same way as the wild type but were much slower in colonizing the host tissue. Double mutants showed an additive effect: they were aberrant in penetration and colonization of plant tissue and, therefore, almost nonpathogenic. To study the structure of the fungal Nox complex in more detail, bcnoxR (encoding a homolog of the mammalian p67phox, a regulatory subunit of the Nox complex) was functionally characterized. The phenotype of ΔbcnoxR mutants is identical to that of ΔbcnoxAB double mutants, providing evidence that BcnoxR is involved in activation of both Bcnox enzymes.


Toxics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 48 ◽  
Author(s):  
Jin-Yong Lee ◽  
Maki Tokumoto ◽  
Gi-Wook Hwang ◽  
Min-Seok Kim ◽  
Tsutomu Takahashi ◽  
...  

Mercury compounds are known to cause central nervous system disorders; however the detailed molecular mechanisms of their actions remain unclear. Methylmercury increases the expression of several chemokine genes, specifically in the brain, while metallothionein-III (MT-III) has a protective role against various brain diseases. In this study, we investigated the involvement of MT-III in chemokine gene expression changes in response to methylmercury and mercury vapor in the cerebrum and cerebellum of wild-type mice and MT-III null mice. No difference in mercury concentration was observed between the wild-type mice and MT-III null mice in any brain tissue examined. The expression of Ccl3 in the cerebrum and of Cxcl10 in the cerebellum was increased by methylmercury in the MT-III null but not the wild-type mice. The expression of Ccl7 in the cerebellum was increased by mercury vapor in the MT-III null mice but not the wild-type mice. However, the expression of Ccl12 and Cxcl12 was increased in the cerebrum by methylmercury only in the wild-type mice and the expression of Ccl3 in the cerebellum was increased by mercury vapor only in the wild-type mice. These results indicate that MT-III does not affect mercury accumulation in the brain, but that it affects the expression of some chemokine genes in response to mercury compounds.


2017 ◽  
Author(s):  
Ye Yu ◽  
Xiaojing Liu ◽  
Xiao Ma ◽  
Zhongjie Zhang ◽  
Na Liu ◽  
...  

AbstractPulpal- and adult-stage minute wing (mw) mutants of the silkworm Bombyx mori have much smaller wings than those of the wild type. Herein, we report the genetic and molecular mechanisms underling the formation of the minute wing. Fine mapping and positional cloning revealed that a palmitoyltransferase ZDHHC18-like gene (BmAPP)was responsible for the mw mutation. CRISPR/Cas9 screening of the BmAPP gene in wild-type embryos revealed that a significant proportion of adults had the mw mutation. In an mw mutant strain, u11, a 10-bp insertion in the promoter of a novel gene resulted in low-level translation of a protein belonging to the DHHC family. A PiggyBac-based transgenic analysis showed that the promoter induced the expression of aBmAPP gene promoter in the wild type but not the mw mutant. These findings indicate that functional deletion of this gene promoter accounts for the mw mutation in silkworm. The possibility that BmAPP gene is involved in Hippo signalling pathway, an evolutionarily conserved signaling pathway that controls organ size, is discussed.


2021 ◽  
Author(s):  
Yanan Chen ◽  
Panpan Feng ◽  
Boyan Tang ◽  
Zongli Hu ◽  
Qiaoli Xie ◽  
...  

Abstract The process of plant senescence is complex and highly coordinated, and is regulated by many endogenous and environmental signals. Ethylene and jasmonic acid are well-known senescence inducers, but their molecular mechanisms for inducing leaf senescence have not been fully elucidated. Here, we studied a receptor gene downstream of an ethylene signal transduction pathway, ETHYLENE RESPONSE FACTOR F5 (SlERF.F5). The silence of SlERF.F5 causes accelerated senescence induced by age, darkness, ethylene, and jasmonic acid. However, overexpression of SlERF.F5 may delay leaf senescence. We further found that silencing of SlERF.F5 inhibited the expression of chlorophyll-related genes CHLH, CHLM, POR, CAO1, GUN4, PPH, SGR1, RBCS, and AUREA genes, and the light-responsive RBCS and LHCA1 gene. Moreover, silencing of SlERF.F5 increases the sensitivity of SlERF.F5-RNAi lines to ethylene and jasmonic acid compared to wild type. In the dark-induced aging experiment, the qRT-PCR analysis showed the expression levels of genes related to the ethylene biosynthesis pathway and the jasmonic acid signaling pathway in SlERF.F5-RNAi lines increased compared with wild type. Yeast two-hybrid experiments showed that SlERF.F5 and SlMYC2 (a transcription factor downstream of the JA receptor) can interact physically, thereby mediating the role of SlERF.F5 in jasmonic acid-induced leaf senescence. Collectively, our research provides new insights into how ethylene and jasmonic acid promote leaf senescence in tomatoes.


2012 ◽  
Vol 303 (7) ◽  
pp. C781-C789 ◽  
Author(s):  
Katherine J. Massey ◽  
Nancy J. Hong ◽  
Jeffrey L. Garvin

Angiotensin II (ANG II) stimulates production of superoxide (O2−) by NADPH oxidase (NOX) in medullary thick ascending limbs (TALs). There are three isoforms of the catalytic subunit (NOX1, 2, and 4) known to be expressed in the kidney. We hypothesized that NOX2 mediates ANG II-induced O2− production by TALs. To test this, we measured NOX1, 2, and 4 mRNA and protein by RT-PCR and Western blot in TAL suspensions from rats and found three catalytic subunits expressed in the TAL. We measured O2− production using a lucigenin-based assay. To assess the contribution of NOX2, we measured ANG II-induced O2− production in wild-type and NOX2 knockout mice (KO). ANG II increased O2− production by 346 relative light units (RLU)/mg protein in the wild-type mice ( n = 9; P < 0.0007 vs. control). In the knockout mice, ANG II increased O2− production by 290 RLU/mg protein ( n = 9; P < 0.007 vs. control). This suggests that NOX2 does not contribute to ANG II-induced O2− production ( P < 0.6 WT vs. KO). To test whether NOX4 mediates the effect of ANG II, we selectively decreased NOX4 expression in rats using an adenovirus that expresses NOX4 short hairpin (sh)RNA. Six to seven days after in vivo transduction of the kidney outer medulla, NOX4 mRNA was reduced by 77%, while NOX1 and NOX2 mRNA was unaffected. In control TALs, ANG II stimulated O2− production by 96%. In TALs transduced with NOX4 shRNA, ANG II-stimulated O2− production was not significantly different from the baseline. We concluded that NOX4 is the main catalytic isoform of NADPH oxidase that contributes to ANG II-stimulated O2− production by TALs.


2018 ◽  
Vol 19 (8) ◽  
pp. 2221 ◽  
Author(s):  
Yangyang Zheng ◽  
Xudong Wang ◽  
Siyuan Liu ◽  
Kewei Zhang ◽  
Zhibo Cai ◽  
...  

To investigate whether the ech42 gene in Clonostachysrosea can improve the biocontrol efficacy of Bacillus amyloliquefaciens and its molecular mechanism. Compared to the wild type, the B. amyloliquefaciens transformed with the ech42 gene exhibited higher chitinase activity. The B. amyloliquefaciens-ech42 also showed significantly higher biocontrol efficiency compared to Botrytiscinerea when tomato plants were pre-treated with B. amyloliquefaciens-ech42. No significant difference in biocontrol efficiency was observed between the wild type and B.amyloliquefaciens-ech42 when tomato plants were first infected by Botrytiscinerea. In addition, the activity of the defense-related enzyme polyphenol oxidase, but not superoxide dismutase, was significantly higher in B. amyloliquefaciens-ech42 than in the wild type. The ech42 enhances the biocontrol efficiency of B.amyloliquefaciens by increasing the capacity of preventative/curative effects in plants, rather than by killing the pathogens.


2011 ◽  
Vol 286 (12) ◽  
pp. 10105-10114 ◽  
Author(s):  
Myat T. Lin ◽  
Alexander A. Shubin ◽  
Rimma I. Samoilova ◽  
Kuppala V. Narasimhulu ◽  
Amgalanbaatar Baldansuren ◽  
...  

The cytochrome bo3 ubiquinol oxidase from Escherichia coli resides in the bacterial cytoplasmic membrane and catalyzes the two-electron oxidation of ubiquinol-8 and four-electron reduction of O2 to water. The one-electron reduced semiquinone forms transiently during the reaction, and the enzyme has been demonstrated to stabilize the semiquinone. The semiquinone is also formed in the D75E mutant, where the mutation has little influence on the catalytic activity, and in the D75H mutant, which is virtually inactive. In this work, wild-type cytochrome bo3 as well as the D75E and D75H mutant proteins were prepared with ubiquinone-8 13C-labeled selectively at the methyl and two methoxy groups. This was accomplished by expressing the proteins in a methionine auxotroph in the presence of l-methionine with the side chain methyl group 13C-labeled. The 13C-labeled quinone isolated from cytochrome bo3 was also used for the generation of model anion radicals in alcohol. Two-dimensional pulsed EPR and ENDOR were used for the study of the 13C methyl and methoxy hyperfine couplings in the semiquinone generated in the three proteins indicated above and in the model system. The data were used to characterize the transferred unpaired spin densities on the methyl and methoxy substituents and the conformations of the methoxy groups. In the wild type and D75E mutant, the constraints on the configurations of the methoxy side chains are similar, but the D75H mutant appears to have altered methoxy configurations, which could be related to the perturbed electron distribution in the semiquinone and the loss of enzymatic activity.


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