We have expressed truncated forms of the insect control protein genes of Bacillus thuringiensis var. kurstaki HD-1(cryIA(b) and HD-73 (cryIA(c) in cotton plants at levels that provided effective control of agronomically important lepidopteran insect pests. Total protection from insect damage of leaf tissue from these plants was observed in laboratory assays when tested with two lepidopteran insects, an insect relatively sensitive to the B.t.k. insect control protein, Trichoplusia ni (cabbage looper) and an insect that is 100 fold less sensitive, Spodoptera exigua (beet armyworm). Whole plants, assayed under conditions of high insect pressure with Heliothis zea (cotton bollworm) showed effective square and boll protection. Immunological analysis of the cotton plants indicated that the insect control protein represented 0.05% to 0.1% of the total soluble protein. We view these results as a major step towards the agricultural use of genetically modified plants with insect resistance in this valuable, high acreage crop.
SummaryAlthough it is one of the major crops in the world, corn has poor nutritional quality for human and animal consumption due to its low lysine content. Here, we report a method
Genetically modified cotton lines have been developed that are tolerant to glyphosate, the active ingredient in the herbicide Roundup. The new lines were generated by Agrobacterium tumfaciens-mediated transfer of a gene encoding 5-enolpyruvylshikimate-3-phosphate synthase isolated from Agrobacterium sp. CP4 (CP4 EPSPS). Lines were screened via greenhouse spray tests and field evaluations to identify agronomically acceptable lines with a commercial level of tolerance to glyphosate. Two lines were characterized. Lines 1445 and 1698 were transformed with different vectors that encode for the CP4 EPSPS and the neomycin phosphotransferase II (NPTII) marker protein. Both lines contain a single DNA insertion that segregates in a typical Mendelian fashion. Line 1445 contains a single copy of the CP4 EPSPS gene, whereas the line 1698 contains two copies of the CP4 EPSPS gene at a single insertion site. The stability of each DNA insertion was demonstrated by Southern analysis across the R3 and R5 generations. The expression levels of the CP4 EPSPS and NPTII were quantitated by ELISA in leaf and seed samples collected in 1993 and 1994 field trials. The use of glyphosate-tolerant cotton will enable the grower to take advantage of additional weed management alternatives. Keywords: Cotton; genetically modified; herbicide tolerant; Roundup
Embryogenic cultured cells of Daucus caota have been shown to synthesize putrescine from exogenously supplied 114Cjarginine at twice the rate of control nonembryogenic cells. In the present paper, the activity of argni decarboxylase (arginine carboxy-lyase, EC 4.1.1.19), an important enzyme in the synthesis of putrescine, was assayed and also found to be elevated by as much as 2-fold in embryogenic cells. This difference between embryogenic and nonembryogenic cells was observed as early as 6 hours after the induction of embryogenesis and appeared not to result from the presence of a diffusible inhibitor or activator. It seemed to be dependent upon concomitant RNA and protein synthesis, as judged using 6-methylpurine and cycloheximide. After cycloheximide addition to the culture medium, arginine decarboxylase activity declined with a half-time of about 30 minutes in both embryogenic and nonembryogenic cells. It is suggested that elevated arginine decarboxylase activity is involved in the mechanism leading to elevated putrescine levels in these cells and hence may play a role in the embryogenic process.In a previous paper (8), results were presented which showed substantial differences between embryogenic and nonembryogenic carrot cells with regard to their metabolism of polyamines. The levels of putrescine and spermidine rose in embryogenic cells compared with the control, whereas the level of spermine fell. Also, the rate of synthesis of putrescine appeared to be about 2-fold higher in embryogenic cells, as judged by the incorporation of radioactivity after a pulse of ["4Clarginine. These differences occurred within 24 hr after transfer of the cells to embryogenic medium.Because polyamines may therefore be involved in the process of carrot embryogenesis, it seemed important to examine the basis for this alteration in polyamine metabolism. To this end, the activity of arginine decarboxylase (arginine carboxy-lyase EC 4.1.1.19) was determined. ADC' has been implicated in the regulation of polyamine biosynthesis in other plant and bacterial systems (4,(11)(12)(13)(14)(15). Its mammalian counterpart, ornithine decarboxylase, varies in response to many kinds of developmental events and environmental stimuli (7,9,10,16,17 mCi/mmol) and 0.01 ml of 5 mm pyridoxal-5'-phosphate. In some cases, these volumes were halved. The test tubes containing all components of the assay were capped with special rubber stoppers fitted with plastic center wells (Kontes Glass Co., K-882310 and K-882320) containing 0.1 ml of 2 N KOH on a Whatman No. 1 paper wick. The reaction was allowed to proceed for 60 min at 30 C in a shaking water bath (100 oscillations/min) and was terminated by the injection of 0.5 ml of 1 N H2SO4 into the reaction solution. After an additional 60 min of shaking, the center wells were removed, and the paper wicks were placed in scintillation vials with 3 ml of H20 and 10 ml of Packard Insta-gel scintillation fluid. Counting efficiency was about 80%1o. Blank values were obtained either by using boiled crude e...
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