Question

Which of the following GM crops is produced by antisense RNA technology where the expression of a native gene is blocked?
A) Bt cotton
B) Golden rice
C) Flavr Savr
D) Golden Mustard

Answer 1

Hint: Antisense RNA technology is one of the methods that are used to downregulate or inhibit a gene expression. It is based on the principle that an antisense nucleic acid sequence base pairs with its complementary sense RNA strand and prevents it from being translated into a protein.

Complete step-by-step answer:
Flavr-Savr tomato Is a genetically modified tomato to increase its shelf life. It is the first genetically engineered crop granted a licence for human consumption. Softening of fruits is largely due to the degradation of the cell wall by the enzyme polygalacturonase (PG). The gene that encodes for PG has been isolated and cloned (pTOM6).
First of all, DNA is isolated from the tomato plant that encodes the enzyme polygalacturonase (PG). Then the PG gene is transferred to a vector of bacteria and complementary DNA (cDNA) is produced. Then cDNA is introduced into a fresh tomato plant to produce a transgenic plant. Now the cDNA of PG encodes for the antisense mRNA, complementary to sense mRNA. The hybridization between sense and antisense RNA renders the sense mRNA ineffective. Consequently, no polygalacturonase is produced hence the fruit ripening is delayed.
So the correct answer is option C .

Note: Transgene is a genetically engineered gene added to plant species. An organism containing a transgene introduced by genetic engineering methods is called transgenic. Transgenics are important as organisms are developed that express novel traits not normally found in other species. For example- extended shelf life of tomato, herbicide-resistant soybean.