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We report the generation of transgenic soybean [Glycine max (L.) Merr.] via Agrobacterium-mediated gene transfers of a cry1A gene (tic107) from Bacillus thuringiensis (Bt) that exhibits a high degree of resistance against the lepidopteran pests Pseudoplusia includens (Walker) (soybean looper), Helicoverpa zea (Boddie) (soybean podworm), and Anticarsia gemmatalis Hübner (velvetbean caterpillar). Three transgenic soybean lines (862, 726, and 781) were evaluated for expression, molecular composition, efficacy against target pests, and agronomic characteristics. We have designed and tested an expression cassette that consistently and reproducibly generates transgenic soybeans that accumulate the tic107 protein at levels as high as 6.12 μg mg-1 of total extractable protein. Expression levels of this magnitude of a Bt insecticidal protein have never been reported in soybean. Previous reports have indicated expression levels 100-fold lower in the highest-expressing lines. In addition, the phenotypes of these high-expressing lines were indistinguishable from their negative segregant and the transformation parent (Asgrow var. ‘A3237’). Insect bioassay data demonstrate complete protection against soybean looper, soybean podworm, and velvetbean caterpillar when negative controls exhibited defoliation as high as 98%. Unlike previous reports of transgenic soybeans, we report here highly efficacious, single-copy, and normal phenotypes of transgenic soybean plants containing the highly expressed cry1A gene. [ABSTRACT FROM AUTHOR]

The Escherichia coli fructose repressor, FruR, is known to regulate expression of several genes concerned with carbon utilization. Using a previously derived consensus sequence for FruR binding, additional potential operators were identified and tested for FruR binding in DNA band migration retardation assays. Operators in the control regions of operons concerned with carbon metabolism bound FruR, while those in operons not concerned with carbon metabolism did not In vivo assays with transcriptional lacZ fusions showed that FruR controls the expression of FruR operator-containing genes encoding key enzymes of virtually every major pathway of carbon metabolism. Moreover, a fruR null mutation altered the rates of utilization of at least 36 carbon sources. In general, oxidation rates for glycolytic substances were enhanced while those for gluconeogenic substances were depressed. Alignment of FruR operators revealed that the consensus sequence for FruR binding is the same for operons that are activated and repressed by FruR and permitted formulation of a revised FruR-binding consensus sequence. The reported observations indicate that FruR modulates the direction of carbon flow by transcriptional activation of genes encoding enzymes concerned with oxidative and gluconeogenic carbon flow and by repression of those concerned with fermentative carbon flow. [ABSTRACT FROM AUTHOR]