Designer Strawberries

Photo courtesy of Barry Whyte Flowers of a strawberry plant that contains new genes.

This month, however, molecular biologists at the Virginia Bioinformatics Institute and the Department of Agriculture at Virginia Tech reported that they have developed a method of transformation that's both fast and thorough, transforming 95% of strawberry plants studied and generating a mature new plant in just four months. The biologists used a simpler berry, the Alpine strawberry, which has two sets of chromosomes instead of the eight sets in the commercial strawberry, Fragaria ananassa. It also has a shorter reproductive cycle, 14 to 15 weeks, which allowed them to produce more mutant plants in a shorter period of time.

To make the transformation process more efficient, the biologists used used a more aggressive strain of Agrobacterium, the cellular shuttle that introduces foreign DNA into the strawberry genome, to guarantee rapid infection. In transforming any given species-whether a fruit, vegetable, or slug- scientists need to know if the foreign DNA has been taken up and integrated. They ensured that very few non-transformed plants slipped through the selection process by using an antibiotic marker called hygromycin piggy-backed with a gene that codes for a specific marker protein known as Green Fluorescent Protein. By looking at the plant tissue under a fluorescent microscope, they were able to see clearly what tissue glowed green and therefore if the plants had been transformed or not with the DNA of interest.

"This method's efficiency is crucial for generating the large numbers of mutants we need to study the function of strawberry genes," said Dr. Janet Slovin, a molecular biologist at the United States Department of Agriculture in Beltsville MD. "It's a major step in developing a system that will allow scientists to identify commercially-important genes, like those that convey health benefits."

The method used by these scientists could also lead to modifications in other fruits of the Rosaceae family, which includes peaches, pears, plums, apples, cherries, raspberries and almonds. The consumption of this family of fruits ranks third in temperate regions.

For more info:

Video: Genes on the Menu
New technologies have a great influence on our daily lives and plant biotechnology is no exception. However, it is a controversial area that is regarded with suspicion. The film addresses the role that GM food is likely to play in our society.

Strawberries by Design
http://www.eurekalert.org/pub_releases/2006-03/vt-sbd031006.php

High-efficiency transformation of strawberry
https://www.vbi.vt.edu/article/articleview/471/1/15/

TV documentary on the policy of patenting genes
http://www.firstscience.com/home/firstscience.tv/patent-on-life_6.html