title: A novel pilin subunit from Xenorhabdus nematophila, an insect pathogen, confers pest resistance in tobacco and tomato.
abstract: Overexpression of insecticidal pilin subunit from Xenorhabdus nematophila protects transgenic tobacco and tomato plants against Helicoverpa armigera. Xenorhabdus nematophila is a pathogenic bacterium producing toxins that kill the larval host. Previously, we characterized a pilin subunit of X. nematophila which was found to be a pore-forming toxin and cytotoxic to the larval hemocytes of Helicoverpa armigera by causing agglutination and lysis of the cells. In the present study, we report the efficacy of the insecticidal pilin subunit expressed in transgenic tobacco and tomato plants for control against H. armigera. A 537 bp mrxA gene encoding the 17 kDa insecticidal pilin subunit was transferred into the genome of tobacco and tomato, respectively, via Agrobacterium-mediated transformation. The stable integration of the 537 bp mrxA gene in the transgenic plants was confirmed by Southern blot analysis and expression of mrxA gene was confirmed by RT-PCR and Western blot analyses. The transgenic plants appeared healthy and phenotypically normal but proved toxic to the insects in insect bioassays, showing 100% insect mortality and reduced damage of the transgenic plants. Based on these observations, it is suggested that pilin subunit can be used as a potential candidate for control of H. armigera and may open new strategies for pest control in agricultural plants.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Punam
authors.initials: P
authors.lastname: Kumari
authors.affiliation: Division of Entomology, Indian Agricultural Research Institute, PUSA, New Delhi, 110012, India.
authors.forename: Gagan Kumar
authors.initials: GK
authors.lastname: Mahapatro
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India. nirupamaban@yahoo.com.
authors.forename: Nirupama
authors.initials: N
authors.lastname: Banerjee
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India. neerasarin@rediffmail.com.
authors.forename: Neera Bhalla
authors.initials: NB
authors.lastname: Sarin
mesh_terms: D000818:Animals; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000469:parasitology; D009036:Moths / Q000382:microbiology / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000469:parasitology*; D014026:Nicotiana / Q000235:genetics / Q000469:parasitology; D020593:Xenorhabdus / Q000235:genetics* / Q000378:metabolism
chemical_list: D036781:Fimbriae Proteins
keywords: Helicoverpa armigera; Insect resistance; Insecticidal pilin subunit; Transgenic tobacco and tomato; Xenorhabdus nematophila