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259 results on '"Love, Andrew J"'

1. Poly ADP-Ribosylation in a Plant Pathogenic Oomycete Phytophthora infestans : A Key Controller of Growth and Host Plant Colonisation.

Author

Samarskaya, Viktoriya O., Koblova, Sofya, Suprunova, Tatiana, Rogozhin, Eugene A., Spechenkova, Nadezhda, Yakunina, Sofiya, Love, Andrew J., Kalinina, Natalia O., and Taliansky, Michael

Subjects
RNA interference, PLANT colonization, SMALL interfering RNA, NUCLEIC acids, PHYTOPHTHORA infestans
Abstract

ADP-ribosylation is a reversible modification of proteins and nucleic acids, which controls major cellular processes, including DNA damage repair, cell proliferation and differentiation, metabolism, stress, and immunity in plants and animals. The involvement of ADP-ribosylation in the life cycle of Dictyostelium and some filamentous fungi has also been demonstrated. However, the role of this process in pathogenic oomycetes has never been addressed. Here, we show that the Phytophthora infestans genome contains two PARP-like protein genes (PiPARP1 and PiPARP2), and provide evidence of PARylation activity for one of them (PiPARP2). Using dsRNA-mediated RNA silencing of the PiPARP2 gene and chemical (pharmacological) inhibition of PARP activity by 3-aminobenzamide (3AB) PARP inhibitor, we demonstrate the critical functional role of ADP-ribosylation in Phytophthora mycelium growth. Virulence test on detached leaves also suggests an important role of ADP-ribosylation in Phytophthora host plant colonisation and pathogenesis. On a practical level, our data suggest that targeting the PARylation system may constitute a novel powerful approach for the management of Phytophthora diseases. [ABSTRACT FROM AUTHOR]

Published
2025
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4. Disruption of Poly(ADP-ribosyl)ation Improves Plant Tolerance to Methyl Viologen-Mediated Oxidative Stress via Induction of ROS Scavenging Enzymes.

Author

Kalinina, Natalia O., Spechenkova, Nadezhda, Ilina, Irina, Samarskaya, Viktoriya O., Bagdasarova, Polina, Zavriev, Sergey K., Love, Andrew J., and Taliansky, Michael

Subjects
APOPTOSIS, GENE silencing, TISSUE viability, REACTIVE oxygen species, OXIDATIVE stress, POLY ADP ribose, ADP-ribosylation
Abstract

ADP-ribosylation (ADPRylation) is a mechanism which post-translationally modifies proteins in eukaryotes in order to regulate a broad range of biological processes including programmed cell death, cell signaling, DNA repair, and responses to biotic and abiotic stresses. Poly(ADP-ribosyl) polymerases (PARPs) play a key role in the process of ADPRylation, which modifies target proteins by attaching ADP-ribose molecules. Here, we investigated whether and how PARP1 and PARylation modulate responses of Nicotiana benthamiana plants to methyl viologen (MV)-induced oxidative stress. It was found that the burst of reactive oxygen species (ROS), cell death, and loss of tissue viability invoked by MV in N. benthamiana leaves was significantly delayed by both the RNA silencing of the PARP1 gene and by applying the pharmacological inhibitor 3-aminobenzamide (3AB) to inhibit PARylation activity. This in turn reduced the accumulation of PARylated proteins and significantly increased the gene expression of major ROS scavenging enzymes including SOD (NbMnSOD; mitochondrial manganese SOD), CAT (NbCAT2), GR (NbGR), and APX (NbAPX5), and inhibited cell death. This mechanism may be part of a broader network that regulates plant sensitivity to oxidative stress through various genetically programmed pathways. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Superchiral near fields detect virus structure

Author

Kakkar, Tarun, Keijzer, Chantal, Rodier, Marion, Bukharova, Tatyana, Taliansky, Michael, Love, Andrew J., Milner, Joel J., Karimullah, Affar S., Barron, Laurence D., Gadegaard, Nikolaj, Lapthorn, Adrian J., and Kadodwala, Malcolm

Published
2020
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16. Host responses to infection by Cauliflower mosaic virus

Author

Love, Andrew J.

Subjects
633, QR Microbiology
Abstract

The role of soluble sugars in the development of symptoms in compatible virus infection was examined in turnip and several Arabidopsis thaliana lines infected with Cauliflower mosaic virus CaMV. In turnip (Brassica campestris cv. Just Right) infected with four CaMV isolates that induced symptoms of differing severity, there were changes in levels of free soluble sugars in infected plants, but the changes showed no direct correlation with either the level of virus replication or symptom severity. This implies that in CaMV-infected turnip, changes in sugar levels probably do not act directly as elicitors of symptom development. CaMV infection in wildtype and putative Arabidopsis sugar signalling mutants had little effect on levels of free soluble sugar during symptom development. Again this observation does not support a role for changes in sugar levels in potentiating the development of symptoms. However on infection, the mutants developed a range of unusual symptom phenotypes and showed differences in level of virus accumulation, when compared with wildtype plants. This suggested a possible link between sugar signalling pathways and symptom development and viral pathogenesis. Soluble sugars have been reported to act as signalling molecules in defence responses. To test this the expression of three PR protein genes, which are reported to be modulatable by sugars and the SA defence pathway, were analysed in infected Arabidopsis. In infected plants, the expression of these genes was greatly elevated, whereas uninfected plants had undetectable levels of expression. Since sugar levels were unaffected during virus infection this suggests that sugars are probably not involved in the invocation of PR defence genes. The temporal and spatial activation of three defence pathways was investigated using defence marker gene promoter::Luciferase reporter plants. Ambidopsis thaliana GST1::Luciferase was used in the analysis of the oxidative burst, Arabidopsis thaliana PDF1.2::Luciferase for the JA/ethylene pathway and tobacco PR-1::Luciferase for the SA pathway. Systemic activation of the JA/ethylene pathway and oxidative burst was detectable two hours after virus inoculation, and continued until 5 dpi. In contrast activation of the SA-mediated defence pathway was first detected 8 days after infection, continuing strongly until at least 19 dpi. The timing of the SA pathway activation coincided with a second burst of increased AtGST1:;Luciferase. However plants stained for H2O2, a product of the oxidative burst, demonstrated that the oxidative burst occurred only in the very early stages of virus infection (3.5 hours- 4 days after inoculation). This suggested that the second phase of G5T7::Luciferase activity is perhaps regulated by other pathways, in the absence of the oxidative burst. The invocation of defence responses during compatible interactions has often been overlooked since the pathogen appears to replicate and move freely in the plant. These results provide strong evidence for a co-ordinated activation of defence pathways in response to infection by a compatible virus pathogen.

Published
2002
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32. High chloride, sulphate and fluoride concentrations in clay-rich aquitard porewater, the North China Plain: evidence of geochemical behavior

Author

Han Dongmei, Cao Guoliang, and Love Andrew J.

Subjects
Environmental sciences, GE1-350
Abstract

The focus of this investigation was to constrain the porewater chemistry from tracer and ion profiles in a 128 m thick clay-rich sequence of Quaternary sediments comprising the clay, silt and fine sand formation in the North China Plain. Porewater are much more saline (1.1-71.0 g/L) than the lower confined groundwaters (0.3-1.3g/L). Chloride profiles from aqueous extraction (AE) (ranging from 117 to 3260 mg/L) generally keep good consistent with that obtained from squeezing test (ST). However, the sulphate and fluoride concentrations by AE (ranging from 340 to 48,700 mg/L and from 8.8 to 144 mg/L, respectively) are far greater than that by ST. Dissolution of evaporites may be responsible for the high Cl/Br ratios greater than 1000, probably indicating recharge occurred during much wetter periods. The original stable isotopic and chemical compositions in the aquitard porewater have been modified by transpiration and evaporation processes concentrating Cl and causing isotopic enrichment during their formation periods. Dissolution of fluorite, hieratite, and cryolite caused by weathering behavior and ion-exchange reactions should be responsible for the high fluoride concentrations in the aquitard porewater. High sulphate levels found in aqueous samples may arise from pyrite oxidation during sampling, storage and/or porewater extraction procedure.

Published
2019
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49. Cauliflower mosaic virus, a compatible pathogen of arabidopsis, engages three distinct defense-signaling pathways and activates rapid systemic generation of reactive oxygen species (1)

Author

Love, Andrew J., Yun, Byung Wook, Laval, Valerie, Loake, Gary J., and Milner, Joel J.

Subjects
Gene silencing -- Research, Arabidopsis thaliana -- Diseases and pests, Arabidopsis thaliana -- Research, Arabidopsis thaliana -- Genetic aspects, Arabidopsis thaliana -- Physiological aspects, DNA -- Research, Biological sciences, Science and technology
Published
2005

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