The production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi is an important component of the defense response of plants. The timing of this natural host defense mechanism was modified to produce fungal-resistant plants. Transgenic tobacco seedlings constitutively expressing a bean chitinase gene under control of the cauliflower mosaic virus 35S promoter showed an increased ability to survive in soil infested with the fungal pathogen Rhizoctonia solani and delayed development of disease symptoms.

To determine the frying stability of corn oils that are genetically modified to contain 65% oleic acid, high-oleic corn oil was evaluated in room odor tests and by total polar compound analysis. Flavor characteristics of french-fried potatoes, prepared in the oil, were also evaluated by trained analytical sensory panelists. In comparison to normal corn oil, hydrogenated corn oil and high-oleic (80 and 90%) sunflower oils, high-oleic corn oil had significantly (P < 0.05) lower total polar compound levels after 20 h of oil heating and frying at 190°C than the other oils. Fried-food flavor intensity was significantly higher in the normal corn oil during the early portion of the frying schedule than in any of the high-oleic or hydrogenated oils; however, after 17.5 h of frying, the potatoes fried in normal corn oil had the lowest intensity of fried-food flavor. Corn oil also had the highest intensities of off-odors, including acrid and burnt, in room odor tests. High-oleic corn oil also was evaluated as a salad oil for flavor characteristics and oxidative stability. Results showed that dry-milled high-oleic corn oil had good initial flavor quality and was significantly (P < 0.05) more stable than dry-milled normal corn oil after oven storage tests at 60°C, as evaluated by flavor scores and peroxide values. Although the high-oleic corn oil had significantly (P < 0.05) better flavor and oxidative stability than corn oil after aging at 60°C, even more pronounced effects were found in high-temperature frying tests, suggesting the advantages of high-oleic corn oil compared to normal or hydrogenated corn oils.

No abstract

As a highly active plant viral promoter that is able to function in a wide variety of cell types, the cauliflower mosaic virus (CaMV) 35S promoter has the potential for harboring a plant enhancer element. We tested this possibility and demonstrated that a 338 base pair fragment isolated from the region upstream of the 35S TATA box can increase the expression of a low-activity heterologous promoter up to the level observed for the intact 35S promoter. This fragment is fully active in both orientations when placed 150 base pairs upstream of the transcription start site. However, the activity of this fragment is sensitive to location, demonstrating a reduction in activity and loss of orientation-independent function when the distance from the transcription start site is increased. By assaying fragments of different sizes, we have also characterized regions that are functional in directing the stimulation of the heterologous promoter.