Gene transfer in corn.

Gene transfer in corn

Recent genetic engineering experimentswith maize, or Indian corn, mark the first time a member of the grass family has been infected by a virus carried by the bacterium Agrobacterium. The procedure, called agroinfection, is the increasingly common laboratory technique used to transfer selected DNA into plants by adding that DNA to the DNA of Agrobacterium, then allowing the bacterium to "colonize" plants -- which it does by transferring part of its DNA (including the foreign, "third party" DNA) into the host plant's own genetic material.

The success with viral DNA -- whichwas used because, among other things, its effects are easily detectable -- demonstrates for the first time that agroinfection is an efficient way to induce foreign DNA expression in corn cells. Moreover, the results, described in the Jan. 8 NATURE, extend the possibilities of using beneficial DNA -- such as those that code for resistance to viruses -- to genetically improve a plant family that includes all the cereal grains, sugarcane and many sources of animal feed.

Researchers at Friedrich Miescher Institutein Basel, Switzerland, and John Inness Institute in Norwich, England, used this method to infect plants with maize streak virus DNA. Characteristic symptoms of the disease appeared seven to 18 days after they inoculated seedlings with viral-DNA-bearing Agrobacterium. N ormally, plants develop the disease only if the virus is intact and transmitted by an insect.

Sc ientists had generally thought thatmembers of the grass family were not amenable to agroinfection, which is considered an efficient way to induce foreign DNA expression in whole plants.