A novel pilin subunit from Xenorhabdus nematophila, an insect pathogen, confers pest resistance in tobacco and tomato

2015 ◽  
Vol 34 (11) ◽  
pp. 1863-1872 ◽  
Author(s):  
Punam Kumari ◽  
Gagan Kumar Mahapatro ◽  
Nirupama Banerjee ◽  
Neera Bhalla Sarin
Keyword(s):  
Pest Resistance ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen ◽  
Pilin Subunit

scholarly journals Insecticidal Pilin Subunit from the Insect Pathogen Xenorhabdus nematophila

2004 ◽  
Vol 186 (19) ◽  
pp. 6465-6476 ◽  
Author(s):  
Puneet Khandelwal ◽  
Devapriya Choudhury ◽  
Ajanta Birah ◽  
M. K. Reddy ◽  
Gorakh Prasad Gupta ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Protein Complex ◽  
Point Mutations ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen ◽  
Larval Host ◽  
Pilin Subunit ◽  
Sugar Derivatives ◽  
Pilin Protein

ABSTRACT Xenorhabdus nematophila is an insect pathogen and produces protein toxins which kill the larval host. Previously, we characterized an orally toxic, large, outer membrane-associated protein complex from the culture medium of X. nematophila. Here, we describe the cloning, expression, and characterization of a 17-kDa pilin subunit of X. nematophila isolated from that protein complex. The gene was amplified by PCR, cloned, and expressed in Escherichia coli. The recombinant protein was refolded in vitro in the absence of its cognate chaperone by using a urea gradient. The protein oligomerized during in vitro refolding, forming multimers. Point mutations in the conserved N-terminal residues of the pilin protein greatly destabilized its oligomeric organization, demonstrating the importance of the N terminus in refolding and oligomerization of the pilin subunit by donor strand complementation. The recombinant protein was cytotoxic to cultured Helicoverpa armigera larval hemocytes, causing agglutination and subsequent release of the cytoplasmic enzyme lactate dehydrogenase. The agglutination of larval cells by the 17-kDa protein was inhibited by several sugar derivatives. The biological activity of the purified recombinant protein indicated that it has a conformation similar to that of the native protein. The 17-kDa pilin subunit was found to be orally toxic to fourth- or fifth-instar larvae of an important crop pest, H. armigera, causing extensive damage to the midgut epithelial membrane. To our knowledge, this is first report describing an insecticidal pilin subunit of a bacterium.

scholarly journals Virulence and Pathogen Multiplication: A Serial Passage Experiment in the Hypervirulent Bacterial Insect-Pathogen Xenorhabdus nematophila

PLoS ONE ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. e15872 ◽  
Author(s):  
Élodie Chapuis ◽  
Sylvie Pagès ◽  
Vanya Emelianoff ◽  
Alain Givaudan ◽  
Jean-Baptiste Ferdy
Keyword(s):  
Serial Passage ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen

Novel insecticidal chitinase from the insect pathogen Xenorhabdus nematophila

2020 ◽  
Vol 159 ◽  
pp. 394-401
Author(s):  
Saquib Mahmood ◽  
Mukesh Kumar ◽  
Punam Kumari ◽  
Gagan Kumar Mahapatro ◽  
Nirupama Banerjee ◽  
...  
Keyword(s):  
Xenorhabdus Nematophila ◽  
Insect Pathogen

scholarly journals CpxRA Regulates Mutualism and Pathogenesis in Xenorhabdus nematophila

2007 ◽  
Vol 73 (24) ◽  
pp. 7826-7836 ◽  
Author(s):  
Erin E. Herbert ◽  
Kimberly N. Cowles ◽  
Heidi Goodrich-Blair
Keyword(s):  
Solid Medium ◽  
Stationary Phases ◽  
Lag Phase ◽  
Xenorhabdus Nematophila ◽  
Wild Type ◽  
Signal Transduction System ◽  
Pilin Subunit ◽  
Filamentous Cell ◽  
Time Required ◽  
Structure Assembly

ABSTRACT The CpxRA signal transduction system, which in Escherichia coli regulates surface structure assembly and envelope maintenance, is involved in the pathogenic and mutualistic interactions of the entomopathogenic bacterium Xenorhabdus nematophila. When ΔcpxR1 cells were injected into Manduca sexta insects, the time required to kill 50% of the insects was twofold longer than the time observed for wild-type cells and the ΔcpxR1 cells ultimately killed 16% fewer insects than wild-type cells killed. During mutualistic colonization of Steinernema carpocapsae nematodes, the ΔcpxR1 mutant achieved colonization levels that were only 38% of the wild-type levels. ΔcpxR1 cells exhibited an extended lag phase when they were grown in liquid LB or hemolymph, formed irregular colonies on solid medium, and had a filamentous cell morphology. A mutant with a cpxRp-lacZ fusion had peaks of expression in the log and stationary phases that were conversely influenced by CpxR; the ΔcpxR1 mutant produced 130 and 17% of the wild-type β-galactosidase activity in the log and stationary phases, respectively. CpxR positively influences motility and secreted lipase activity, as well as transcription of genes necessary for mutualistic colonization of nematodes. CpxR negatively influences the production of secreted hemolysin, protease, and antibiotic activities, as well as the expression of mrxA, encoding the pilin subunit. Thus, X. nematophila CpxRA controls expression of envelope-localized and secreted products, and its activity is necessary for both mutualistic and pathogenic functions.

Characterization of a cytotoxic pilin subunit of Xenorhabdus nematophila

2004 ◽  
Vol 314 (4) ◽  
pp. 943-949 ◽  
Author(s):  
Puneet Khandelwal ◽  
Rakesh Bhatnagar ◽  
Devapriya Choudhury ◽  
Nirupama Banerjee
Keyword(s):  
Xenorhabdus Nematophila ◽  
Pilin Subunit

scholarly journals The xaxAB Genes Encoding a New Apoptotic Toxin from the Insect Pathogen Xenorhabdus nematophila Are Present in Plant and Human Pathogens

2007 ◽  
Vol 282 (13) ◽  
pp. 9571-9580 ◽  
Author(s):  
Fabienne Vigneux ◽  
Robert Zumbihl ◽  
Grégory Jubelin ◽  
Carlos Ribeiro ◽  
Joël Poncet ◽  
...  
Keyword(s):  
Xenorhabdus Nematophila ◽  
Human Pathogens ◽  
Insect Pathogen ◽  
Genes Encoding

USE OF CELL AND MOLECULAR GENETIC MANIPULATION TO IMPROVE PASTURE PLANTS

1988 ◽  
pp. 67-72
Author(s):  
D.W.R. White
Keyword(s):  
Cell Culture ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Nutritional Quality ◽  
Rust Resistance ◽  
Herbicide Tolerance ◽  
Pest Resistance ◽  
Crown Rust ◽  
Wide Range ◽  
Pasture Plants

Cell culture and genetic engineering techniques can be used to develop improved pasture plants. To utilise these methods we have developed procedures for regenerating plants from tissue cultures of perennial ryegrass and white clover. In both, the plant genotype influences regeneration capacity. There was significant genetic variation among regenerated perennial ryegrass plants in a wide range of characteristics. Most of the regenerants were resIstant to crown rust and this trait was highly heritable. This rust resistance is being used to breed a new ryegrass cultivar. A system for introducing cloned genes into white clover is described. This capability is bemg used to incorporate genes with the potential to improve nutritional quality and pest resistance. Other possibilities for engineering genetic improvements in white clover, genes conferring herbicide tolerance and resistance to white clover mosaic virus, are briefly outlined. Keywords: Lolium perenne, Trifolium repens, cell culture, somaclonal variation, crown rust resistance, transformation, cloned genes, nutritional quality, proteinase inhibitors, Bt toxins, pest resistance, WCMV viral cross-protection, herbicide tolerance, Agrobacterium, Bacillus thuringenisis.

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