title: A novel insecticidal GroEL protein from Xenorhabdus nematophila confers insect resistance in tobacco.
abstract: Xenorhabdus nematophila is an entomopathogenic bacteria. It secretes a GroEL homolog, XnGroEL protein, toxic to its larval prey. GroEL belongs to the family of molecular chaperones and is required for proper folding of cellular proteins. Oral ingestion of insecticidal XnGroEL protein is toxic to Helicoverpa armigera, leading to cessation of growth and development of the larvae. In the present study, the insecticidal efficacy of XnGroEL against H. armigera has been evaluated in transgenic tobacco plant expressing the protein. A 1.7-kb gene encoding the 58-kDa XnGroEL protein was incorporated into the tobacco genome via Agrobacterium-mediated transformation. The stable integration of the transgene was confirmed by Southern blot analysis and its expression by RT-PCR and western blot analyses in transgenic plants. The transgenic lines showed healthy growth and were phenotypically normal. Insect bioassays revealed significant reduction of 100 % in the survival of larvae (p < 0.001) and 55-77 % reduction in plant damage (p < 0.05 and p < 0.001) compared to the untransformed and vector control plants. The results demonstrate that XnGroEL is a novel potential candidate for imparting insect resistance against H. armigera in plants.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Punam
authors.initials: P
authors.lastname: Kumari
authors.forename: Shashi
authors.initials: S
authors.lastname: Kant
authors.forename: Shazmira
authors.initials: S
authors.lastname: Zaman
authors.forename: Gagan Kumar
authors.initials: GK
authors.lastname: Mahapatro
authors.forename: Nirupama
authors.initials: N
authors.lastname: Banerjee
authors.forename: Neera Bhalla
authors.initials: NB
authors.lastname: Sarin
mesh_terms: D000818:Animals; D018834:Chaperonin 60 / Q000235:genetics* / Q000378:metabolism; D004731:Endotoxins / Q000235:genetics; D007313:Insecta / Q000472:pathogenicity; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics* / Q000469:parasitology; D020593:Xenorhabdus / Q000235:genetics*
chemical_list: D018834:Chaperonin 60; D004731:Endotoxins