title: Development of transgenic sorghum for insect resistance against the spotted stem borer (Chilo partellus).
abstract: Transgenic sorghum plants expressing a synthetic cry1Ac gene from Bacillus thuringiensis (Bt) under the control of a wound-inducible promoter from the maize protease inhibitor gene (mpiC1) were produced via particle bombardment of shoot apices. Plants were regenerated from the transformed shoot apices via direct somatic embryogenesis with an intermittent three-step selection strategy using the herbicide Basta. Molecular characterisation based on polymerase chain reaction and Southern blot analysis revealed multiple insertions of the cry1Ac gene in five plants from three independent transformation events. Inheritance and expression of the Bt gene was confirmed in T(1) plants. Enzyme-linked immunosorbant assay indicated that Cry1Ac protein accumulated at levels of 1-8 ng per gram of fresh tissue in leaves that were mechanically wounded. Transgenic sorghum plants were evaluated for resistance against the spotted stem borer (Chilo partellus Swinhoe) in insect bioassays, which indicated partial resistance to damage by the neonate larvae of the spotted stem borer. Reduction in leaf damage 5 days after infestation was up to 60%; larval mortality was 40%, with the surviving larvae showing a 36% reduction in weight over those fed on control plants. Despite the low levels of expression of Bt delta-endotoxin under the control of the wound-inducible promoter, the transgenic plants showed partial tolerance against first instar larvae of the spotted stem borer.
authors.affiliation: Genetic Transformation Laboratory, International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad 502324, India.
authors.forename: V
authors.initials: V
authors.lastname: Girijashankar
authors.forename: H C
authors.initials: HC
authors.lastname: Sharma
authors.forename: Kiran K
authors.initials: KK
authors.lastname: Sharma
authors.forename: V
authors.initials: V
authors.lastname: Swathisree
authors.forename: L Sivarama
authors.initials: LS
authors.lastname: Prasad
authors.forename: B V
authors.initials: BV
authors.lastname: Bhat
authors.forename: Monique
authors.initials: M
authors.lastname: Royer
authors.forename: Blanca San
authors.initials: BS
authors.lastname: Secundo
authors.forename: M Lakshmi
authors.initials: ML
authors.lastname: Narasu
authors.forename: I
authors.initials: I
authors.lastname: Altosaar
authors.forename: N
authors.initials: N
authors.lastname: Seetharama
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D009036:Moths / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000469:parasitology*; D016133:Polymerase Chain Reaction; D045868:Sorghum / Q000235:genetics / Q000469:parasitology*; D014170:Transformation, Genetic; D019076:Transgenes
chemical_list: D017931:DNA Primers