TransformationWords
Getting More Bang for our Bite: Fast Transforming Strawberries Pave Way for Vitamin-Packed Fruit
The food pyramid is a guideline, not a lost monument in Egypt. But it
would seem so from the way people discount it, eating ridiculously low amounts of fruits and vegetables for example, especially in the West. Now, a superfast method of introducing DNA into strawberries could compensate for this by helping scientists to identify key genes, like those involved in antioxidiant production, so as to pack more nutrition into each berry, however few, that humans bite.
Strawberries, like all fruits, provide compounds that are essential to life. They are a major source of
phytochemicals, which reduce cancer risk, and they also happen to be an especially important source of vitamin C. Strawberries actually provide more of this vitamin than an orange would.
But even though strawberries pack a lot of nutritional punch, scientists say these fleshy, red fruits could be engineered to produce even more. That would be an important step towards improving human health since strawberries are widely consumed; in the list of the world’s economically important crops, their family—the Rosaceae family—ranks third.
Until now, however, though scientists have been able to engineer foods like corn and soybeans, they haven’t been able to touch the genome of the commercial strawberry. Its cumbersome size—8 sets of chromosomes— and lengthy life cycle have made this fruit more difficult to transform than others. Transformation, a process which introduces foreign DNA into a genome, must occur for scientists to identify genes and understand their functions. All previous attempts at transformation in strawberries have failed though. And since scientists can’t identify which strawberry genes do what, they surely haven’t been able to engineer them.
This month, however, molecular biologists at Virginia Polytechnic Institute in Blacksburg, Virginia, report the development of a method of transformation that’s both fast and thorough, transforming 95% of berries involved and doing it relatively quickly, in just 4 months. “This method introduces DNA into lots of strawberries extremely effciently so that we get a large crop of mutants,” said lead investigator Vladimir Shulaev.
Shulaev and his colleagues achieved this efficiency for two reasons. First, they used a simpler berry. All strawberries have 7 basic chromosomes in common and vary only in number of chromosome sets. While the commercial strawberry, Fragaria ananassa, has 8 sets, the species Shulaev selected, known as the Alpine strawberry, has only two. It also has a shorter reproductive cycle: 14 to 15 weeks. “The trick, which is new, was to find a variety of berry that could be easily transformed, “ said Janet Slovin, an expert on plant development at the United States Department of Agriculture. “Shulaev did that.”
His team also took painstaking steps to improve the transformation process, to yield as many mutant berries as quickly as possible, in other words. To guarantee rapid infection, they used a more aggressive strain of Agrobacterium, the cellular shuttle that introduces foreign DNA into the strawberry genome. They also ensured that very few non-transformed plants slipped through the selection process by using a fierce antibiotc known as hygromycin. In transforming any given species—whether a fruit, vegetable, or slug—the foreign DNA used often confers antiobiotic resistance. That way, selection for successful transformants simply boils down to which individuals surive in the presence of an antibiotic.
“This method’s efficiency is crucial for generating the large numbers of mutants we need to study the function of strawberry genes,” said Slovin, “and it’s a major step in developing a system that will allow scientists to identify commercially important genes, like those that convey health benefits.” Shulaev and his colleagues have paved the way for making a better berry.
Journal Reference: Planta DOI 10.1007/s000425-005-0170-3
.MGW.
The food pyramid is a guideline, not a lost monument in Egypt. But it
would seem so from the way people discount it, eating ridiculously low amounts of fruits and vegetables for example, especially in the West. Now, a superfast method of introducing DNA into strawberries could compensate for this by helping scientists to identify key genes, like those involved in antioxidiant production, so as to pack more nutrition into each berry, however few, that humans bite.
Strawberries, like all fruits, provide compounds that are essential to life. They are a major source of
phytochemicals, which reduce cancer risk, and they also happen to be an especially important source of vitamin C. Strawberries actually provide more of this vitamin than an orange would.
But even though strawberries pack a lot of nutritional punch, scientists say these fleshy, red fruits could be engineered to produce even more. That would be an important step towards improving human health since strawberries are widely consumed; in the list of the world’s economically important crops, their family—the Rosaceae family—ranks third.
Until now, however, though scientists have been able to engineer foods like corn and soybeans, they haven’t been able to touch the genome of the commercial strawberry. Its cumbersome size—8 sets of chromosomes— and lengthy life cycle have made this fruit more difficult to transform than others. Transformation, a process which introduces foreign DNA into a genome, must occur for scientists to identify genes and understand their functions. All previous attempts at transformation in strawberries have failed though. And since scientists can’t identify which strawberry genes do what, they surely haven’t been able to engineer them.
This month, however, molecular biologists at Virginia Polytechnic Institute in Blacksburg, Virginia, report the development of a method of transformation that’s both fast and thorough, transforming 95% of berries involved and doing it relatively quickly, in just 4 months. “This method introduces DNA into lots of strawberries extremely effciently so that we get a large crop of mutants,” said lead investigator Vladimir Shulaev.
Shulaev and his colleagues achieved this efficiency for two reasons. First, they used a simpler berry. All strawberries have 7 basic chromosomes in common and vary only in number of chromosome sets. While the commercial strawberry, Fragaria ananassa, has 8 sets, the species Shulaev selected, known as the Alpine strawberry, has only two. It also has a shorter reproductive cycle: 14 to 15 weeks. “The trick, which is new, was to find a variety of berry that could be easily transformed, “ said Janet Slovin, an expert on plant development at the United States Department of Agriculture. “Shulaev did that.”
His team also took painstaking steps to improve the transformation process, to yield as many mutant berries as quickly as possible, in other words. To guarantee rapid infection, they used a more aggressive strain of Agrobacterium, the cellular shuttle that introduces foreign DNA into the strawberry genome. They also ensured that very few non-transformed plants slipped through the selection process by using a fierce antibiotc known as hygromycin. In transforming any given species—whether a fruit, vegetable, or slug—the foreign DNA used often confers antiobiotic resistance. That way, selection for successful transformants simply boils down to which individuals surive in the presence of an antibiotic.
“This method’s efficiency is crucial for generating the large numbers of mutants we need to study the function of strawberry genes,” said Slovin, “and it’s a major step in developing a system that will allow scientists to identify commercially important genes, like those that convey health benefits.” Shulaev and his colleagues have paved the way for making a better berry.
Journal Reference: Planta DOI 10.1007/s000425-005-0170-3
.MGW.
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