P<scp>ERSPECTIVES ON</scp>P<scp>LANT AND</scp>S<scp>OIL</scp>N<scp>EMATOLOGY</scp>

Barker, K. R.

doi:10.1146/annurev.phyto.41.052002.095647

Cited by 19 publications

(10 citation statements)

References 73 publications

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“…Recently, interactions among the microorganism, nematode target, plant and environment have been well reviewed and emphasized (Kerry, 2000; Barker, 2003; Davies, 2005; Dong & Zhang, 2006). Sustainable working methodologies have been proposed, including integrated pest management (IPM).…”

Section: Resultsmentioning

confidence: 99%

Bacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospects

Tian

Yang

Zhang

2007

FEMS Microbiology Ecology

339

191

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As a group of important natural enemies of nematode pests, nematophagous bacteria exhibit diverse modes of action: these include parasitizing; producing toxins, antibiotics, or enzymes; competing for nutrients; inducing systemic resistance of plants; and promoting plant health. They act synergistically on nematodes through the direct suppression of nematodes, promoting plant growth, and facilitating the rhizosphere colonization and activity of microbial antagonists. This review details the nematophagous bacteria known to date, including parasitic bacteria, opportunistic parasitic bacteria, rhizobacteria, Cry protein-forming bacteria, endophytic bacteria and symbiotic bacteria. We focus on recent research developments concerning their pathogenic mechanisms at the biochemical and molecular levels. Increased understanding of the molecular basis of the various pathogenic mechanisms of the nematophagous bacteria could potentially enhance their value as effective biological control agents. We also review a number of molecular biological approaches currently used in the study of bacterial pathogenesis in nematodes. We discuss their merits, limitations and potential uses.

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Section: Resultsmentioning

confidence: 99%

Bacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospects

Tian

Yang

Zhang

2007

FEMS Microbiology Ecology

339

191

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“…They were reared on an artificial diet (a wheat germ‐based basic diet with a vitamin mix) in a climate chamber at 24°C and 70% humidity under a 16/8‐hr day/night light cycle. Root‐knot nematode, M. incognita , is a globally distributed plant parasite that feeds on the roots of numerous host plants, including commercial tobacco Nicotiana tabacum (Barker, ; Koenning et al, ), in addition to being found in the natural habitat of N. attenuata plants (R. Machado, personal communication). Second‐stage juveniles (J2s) of M. incognita (nematode hereafter) were obtained from a biological supply company (Hettema Zaaizaad en Pootgoed Coöperatie [HZPC Holland B.V.], Metslawier, the Netherlands).…”

Section: Methodsmentioning

confidence: 99%

Legacy effects of herbivory enhance performance and resistance of progeny plants

Kafle

Wurst

2018

Journal of Ecology

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Herbivory‐induced changes in plant resistance and tolerance traits can mediate the interaction between spatially and temporally separated above‐ and below‐ground herbivores. However, it is unknown how long the impact of transient herbivory events last or if legacy effects can be detected systemically in the plant and across plant generations. Here, we studied the impact of transient above‐ground herbivory by the specialist caterpillar Manduca sexta on the plant traits of wild tobacco Nicotiana attenuata and the consequences for below‐ground root‐knot nematodes Meloidogyne incognita in short‐term, long‐term, and transgenerational experiments. In the short‐ and long‐term experiments, above‐ and below‐ground herbivory had significant, albeit independent, impacts on key plant traits such as plant biomass, nutrient content, and secondary metabolites. In addition, herbivory influenced fitness parameters such as seed yield and quality. In the long‐term and transgenerational experiments, transient above‐ground herbivory had facilitating effects on nematodes, irrespective of any treatments of the parental plants. We found evidence for transgenerational legacy effects of both above‐ and below‐ground herbivory on the resistance of progeny plants against above‐ground herbivores. Additionally, below‐ground herbivory in the parental generation increased the root biomass of progeny plants. Synthesis. Our results suggest that herbivory may have a long‐term impact on plant fitness by improving the performance of progeny plants challenged by above‐ and below‐ground herbivory.

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“…Importantly, the inactivation specificity of AtGCL compared with those of GCL from T. brucei (20), Ascaris suum (32), and Onchocerca volvulus (33) suggests that the design of anti-nematode compounds is possible. Although these nematodes are human parasites, the generation of inhibitors against nematodes that attack crop and non-crop plants can also be envisioned (40).…”

Section: Expression and Purification Of Atgcl-mentioning

confidence: 99%

Arabidopsis thaliana Glutamate-Cysteine Ligase

Jez

Cahoon

Chen

2004

Journal of Biological Chemistry

129

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In plants, glutathione accumulates in response to different stress stimuli as a protective mechanism, but only limited biochemical information is available on the plant enzymes that synthesize glutathione. Glutamatecysteine ligase (GCL) catalyzes the first step in glutathione biosynthesis and plays an important role in regulating the intracellular redox environment. Because the putative Arabidopsis thaliana GCL (AtGCL) displays no significant homology to the GCL from bacteria and other eukaryotes, the identity of this protein as a GCL has been debated. We have purified AtGCL from an Escherichia coli expression system and demonstrated that the recombinant enzyme catalyzes the ATP-dependent formation of ␥-glutamylcysteine from glutamate (K m ‫؍‬ 9.1 mM) and cysteine (K m ‫؍‬ 2.7 mM). Glutathione feedback inhibits AtGCL (K i ϳ1.0 mM). As with other GCL, buthionine sulfoximine and cystamine inactivate the Arabidopsis enzyme but with inactivation rates much slower than those of the mammalian, bacterial, and nematode enzymes. The slower inactivation rates observed with AtGCL suggest that the active site differs structurally from that of other GCL. Global fitting analysis of initial velocity data indicates that a random terreactant mechanism with a preferred binding order best describes the kinetic mechanism of AtGCL. Unlike the mammalian GCL, which consists of a catalytic subunit and a regulatory subunit, AtGCL functions and is regulated as a monomeric protein. In response to redox environment, AtGCL undergoes a reversible conformational change that modulates the enzymatic activity of the monomer. These results explain the reported posttranslational change in AtGCL activity in response to oxidative stress.Regulation of the intracellular redox environment is critical in cellular physiology for influencing signaling pathways and cell fate in response to stress (1). In plants, as in other organisms, glutathione plays multiple roles as protection against various environmental stresses (2). As an antioxidant, glutathione quenches reactive oxygen species and is involved in the ascorbate-glutathione cycle that eliminates peroxide (2). Plants use glutathione for the detoxification of xenobiotics (3), herbicides (4), air pollutants such as sulfur dioxide and ozone (5, 6), and heavy metals (7). Although glutathione accumulates in response to different stress stimuli in plants, the structural and kinetic properties of the plant enzymes responsible for its production remain biochemically uncharacterized.Glutathione synthesis occurs in two ATP-dependent steps. In the first reaction, glutamate-cysteine ligase (GCL) 1 (EC 6.3.2.2) catalyzes formation of the dipeptide ␥-glutamylcysteine from cysteine and glutamate (Scheme I). Addition of glycine to the dipeptide occurs in a second reaction, catalyzed by glutathione synthetase. Of the two enzymes, GCL appears to be rate-limiting (8). Exposure to heavy metals increases the levels of GCL mRNA in Brassica juncea and activates transcription of both GCL and glutathione synthetase in Arabid...

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PERSPECTIVES ONPLANT ANDSOILNEMATOLOGY

Cited by 19 publications

References 73 publications

Bacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospects

Bacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospects

Legacy effects of herbivory enhance performance and resistance of progeny plants

Arabidopsis thaliana Glutamate-Cysteine Ligase

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