Question

The transgenic tomato variety 'FlavrSavr' had a greatly improved shelf-life and general quality. Which one of the following technologies was used to achieve this feat?

• A. Genome editing
• B. Antisense RNA
• C. RNA interference
• D. RNA editing

Hint:

The Flavr Savr tomato is the classic historical example of the practical application of Antisense RNA technology to silence the polygalacturonase gene.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The Flavr Savr tomato was the first genetically engineered crop approved for human consumption.
It was developed to solve the shelf-life limitations of standard tomatoes, which soften rapidly during transport due to cell wall degradation.

Step 2: Detailed Explanation:
The ripening and softening of tomatoes are accelerated by the enzyme polygalacturonase (PG), which degrades pectin in the plant cell wall.
To suppress the expression of this enzyme, scientists introduced an antisense gene construct into the tomato genome.
This transgenic construct contains the polygalacturonase gene sequence oriented in the reverse (antisense) direction under the control of a plant promoter.
During transcription, this construct produces an antisense RNA molecule that is complementary to the sense mRNA produced by the endogenous PG gene.
The sense and antisense RNA molecules base-pair to form double-stranded RNA, which blocks translation of the PG enzyme.
This down-regulation of polygalacturonase slows pectin degradation, allowing the tomato to remain firm and develop flavor on the vine longer.
Although RNA interference (C) and genome editing (A) are modern gene-silencing technologies, they were not used to develop this variety in the early 1990s.

Step 3: Final Answer:
The technology used to develop the Flavr Savr tomato was Antisense RNA, corresponding to option (B).