Efficient transformation of rice (Oryza sativa L.) mediated by Agrobacterium and sequence analysis of the boundaries of the T-DNA

A large number of morphologically normal, fertile, transgenic rice plants were obtained by co-cultivation of rice tissues with Agrobacterium tumefaciens. The efficiency of transformation was similar to that obtained by the methods used routinely for transformation of dicotyledons with the bacterium. Stable integration, expression and inheritance of transgenes were demonstrated by molecular and genetic analysis of transformants in the R0, R1 and R2 generations. Sequence analysis revealed that the boundaries of the T-DNA in transgenic rice plants were essentially identical to those in transgenic dicotyledons. Calli induced from scutella were very good starting materials. A strain of A. tumefaciens that carried a so-called 'super-binary' vector gave especially high frequencies of transformation of various cultivars of japonica rice that included Koshihikari, which normally shows poor responses in tissue culture.

Source: The Plant Journal (1994) vol. 6, p. 271-282

Benefits of Biotechnology

• Protection of the environment: Scientists have made some foods, such as papayas and potatoes, more resistant to disease. These crops need less chemical spray to protect them from harmful insects or viruses, which is better for water and wildlife. Other crops are protected from herbicides that are used to control weeds, thus allowing farmers to conserve soil by tilling the ground less often.

• Greater Crop Yields: Farmers can use biotechnology to help plants survive, warding off insects and better tolerance to herbicides. This allows a better harvest from these hardier plants.

• Better Tasting, Fresher Foods: Sweeter peppers and tomatoes that ripen more slowly are examples of how biotechnology can produce fresher and better tasting food.

• Grow more food on less land: By the year 2050, the earth’s population is estimated to be nine billion people. Using biotechnology, farmers can produce more crops on the land they already have. This way, countries do not have to devote more land to farming. In turn, developing countries can benefit most, since they will have the largest population growth.

• Keep food safe to eat: Scientists can more accurately find unwanted viruses and bacteria that may be present in food. This will cause an even lower risk of food-borne illnesses. Some types of fungus, which can be found in corn, release substances that can harm animals that eat them. These substances are already regulated in the United States, and biotechnology provides another tool that can help further reduce the amount of these substances in corn.

• New food varieties: Biotechnology can extend advances in cross-breeding, allowing for new food varieties. For example, seedless melons and mini avocadoes. Farmers can also develop food with better flavor and a better nutrient profile.

The Lipoxygenase pathway

Lipid peroxidation is common to all biological systems, both appearing in developmentally and environmentally regulated processes of plants. The hydroperoxy polyunsaturated fatty acids, synthesized by the action of various highly specialized forms of lipoxygenases, are substrates of at least seven different enzyme families. Signaling compounds such as jasmonates, antimicrobial and antifungal compounds such as leaf aldehydes or divinyl ethers, and a plant-specific blend of volatiles including leaf alcohols are among the numerous products. Cloning of many lipoxygenases and other key enzymes within the lipoxygenase pathway, as well as analyses by reverse genetic and metabolic profiling, revealed new reactions and the first hints of enzyme mechanisms, multiple functions, and regulation. These aspects are reviewed with respect to activation of this pathway as an initial step in the interaction of plants with pathogens, insects, or abiotic stress and at distinct stages of development.

Source: Annual review of plant biology (2002) vol. 53, p. 275-297

The Jasmonate Signal Pathway

Plant responses to many biotic and abiotic stresses are orchestrated locally and systemically by signaling molecules known as the jasmonates (JAs). JAs also regulate such diverse processes as pollen maturation and wound responses in Arabidopsis.
The JA signal pathway involves several signal transduction events: the perception of the primary wound or stress stimulus and transduction of the signal locally and systemically; the perception of this signal and induction of JA biosynthesis; the perception of JA and induction of responses; and finally, integration of JA signaling with outputs from the SA, ethylene, and other signaling pathways.

Source: The Plant Cell (2002) vol. 14, p. S153-S164

Which Fruits and Vegetables Are the Most Toxic?

10 most toxic conventionally grown fruits and vegetables (in order of pesticide toxicity levels):

- Peaches
- Apples
- Sweet Bell Peppers (11 different pesticides found on a single pepper)
- Celery
- Nectarines
- Strawberries
- Cherries
- Lettuce
- Grapes
- Pears (86 percent of samples tested with detectable pesticides)

10 least toxic conventionally grown fruits and vegetables (in descending order of pesticide toxicity levels):

- Cabbage
- Bananas
- Kiwi
- Asparagus (7 percent of samples tested with detectable pesticides)
- Sweet Peas
- Mangoes
- Pineapples
- Sweet Corn
- Avocado
- Onions (1 pesticide found on a single onion)

Source: Health.msn.com