What is RNA interference (RNAi)? Describe the cellular mechanism of RNA interference and explain how it is used to develop nematode-resistant tobacco plants.

Q: What is RNA interference (RNAi)? Describe the cellular mechanism of RNA interference and explain how it is used to develop nematode-resistant tobacco plants.

Introduction to RNA Interference (RNAi)\nRNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. It is a method of cellular defense common in all eukaryotic organisms. Mechanism of RNAi Initiation: The process is initiated by double-stranded RNA (dsRNA) molecules that can originate from virus infection or mobile genetic elements (transposons). Cleavage by Dicer: The complementary dsRNA binds to and is cleaved by an enzyme called Dicer into small interfering RNAs (siRNAs) of about 21-23 nucleotides. RISC Assembly: These siRNAs are incorporated into the RNA-induced silencing complex (RISC). Inside the complex, the double-stranded siRNA unwinds, and one strand is degraded, while the remaining guide strand helps RISC recognize the target mRNA. Target Degradation: The guide strand base-pairs with the complementary sequence on the target mRNA, leading to its cleavage or inhibition of translation, thus silencing the specific gene. Application in Nematode-Resistant Tobacco Plants\nA nematode named Meloidegyne incognita infects the roots of tobacco plants, causing a great reduction in yield. To prevent this infection, a novel strategy based on RNAi was adopted: Specific nematode genes (essential for their survival and parasitism) were introduced into the host tobacco plant using Agrobacterium vectors. The introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. Since these two RNAs are complementary to each other, they formed double-stranded RNA (dsRNA) which initiated the RNAi pathway. When the invading nematode feeds on the transgenic tobacco plant, the dsRNA from the plant enters the nematode's cells. This triggers the RNAi response in the nematode, silencing its vital genes. As a result, the parasite cannot survive in the transgenic host, protecting the plant from damage.

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Introduction to RNA Interference (RNAi)
RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. It is a method of cellular defense common in all eukaryotic organisms. Mechanism of RNAi Initiation: The process is initiated by double-stranded RNA (dsRNA) molecules that can originate from virus infection or mobile genetic elements (transposons). Cleavage by Dicer: The complementary dsRNA binds to and is cleaved by an enzyme called Dicer into small interfering RNAs (siRNAs) of about 21-23 nucleotides. RISC Assembly: These siRNAs are incorporated into the RNA-induced silencing complex (RISC). Inside the complex, the double-stranded siRNA unwinds, and one strand is degraded, while the remaining guide strand helps RISC recognize the target mRNA. Target Degradation: The guide strand base-pairs with the complementary sequence on the target mRNA, leading to its cleavage or inhibition of translation, thus silencing the specific gene. Application in Nematode-Resistant Tobacco Plants
A nematode named Meloidegyne incognita infects the roots of tobacco plants, causing a great reduction in yield. To prevent this infection, a novel strategy based on RNAi was adopted: Specific nematode genes (essential for their survival and parasitism) were introduced into the host tobacco plant using Agrobacterium vectors. The introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. Since these two RNAs are complementary to each other, they formed double-stranded RNA (dsRNA) which initiated the RNAi pathway. When the invading nematode feeds on the transgenic tobacco plant, the dsRNA from the plant enters the nematode's cells. This triggers the RNAi response in the nematode, silencing its vital genes. As a result, the parasite cannot survive in the transgenic host, protecting the plant from damage.

CBSE · Class 12 · Biology · Biotechnology and its ApplicationsWhat is RNA interference (RNAi)? Describe the cellular mechanism of RNA interference and explain how it is used to develop nematode-resistant tobacco plants.

Introduction to RNA Interference (RNAi)\nRNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. It is a method of cellular defense common in all eukaryotic organisms.

Mechanism of RNAi

Application in Nematode-Resistant Tobacco Plants\nA nematode named Meloidegyne incognita infects the roots of tobacco plants, causing a great reduction in yield. To prevent this infection, a novel strategy based on RNAi was adopted: