Three tomato plants vary in the shape of their leaves: A has smooth edges on its leaves, B has wavy edges on its leaves, and C has smooth edges with bumps in the center of the leaf. Their genomes are the presence of three siRNAs as shown in the table below. Each plant is also tested to see if it is susceptible to attack by herbivorous beetles.PlantsiRNA 1siRNA 2siRNA 3Susceptible to BeetlesAYesNoNoYesBYesYesNoYesCYesNoYesNo Part A: Identify the role of each siRNA. Explain how the siRNAs do their jobs. Part B: Decipher the connection between the phenotypes and susceptibility to beetles and explain how you deciphered this. (4 points)

Question

Three tomato plants vary in the shape of their leaves: A has smooth edges on its leaves, B has wavy edges on its leaves, and C has smooth edges with bumps in the center of the leaf. Their genomes are the presence of three siRNAs as shown in the table below. Each plant is also tested to see if it is susceptible to attack by herbivorous beetles.PlantsiRNA 1siRNA 2siRNA 3Susceptible to BeetlesAYesNoNoYesBYesYesNoYesCYesNoYesNo Part A: Identify the role of each siRNA. Explain how the siRNAs do their jobs. Part B: Decipher the connection between the phenotypes and susceptibility to beetles and explain how you deciphered this. (4 points)

Answer 1

Part A:

- siRNA 1: This siRNA is present in plants A and C. It is not present in plant B. It helps in providing resistance against beetle attack.
- siRNA 2: This siRNA is present in plants B and C. It is not present in plant A. It also contributes to resistance against beetle attack.
- siRNA 3: This siRNA is present in plants C only. It is not present in plants A and B. It plays a role in providing resistance against beetle attack.

siRNAs are small RNA molecules that work by silencing specific target genes. They do this by binding to the messenger RNA (mRNA) molecules that are produced from the corresponding target genes. This binding prevents the target genes from being expressed or translated into proteins, thus reducing their activity or completely shutting them down. In the case of these tomato plants, the presence or absence of specific siRNAs determines the expression levels of certain genes involved in defense mechanisms against beetle attacks. By targeting and silencing these genes, the siRNAs help in providing resistance to beetles.

Part B:

Based on the information given, we can decipher the connection between the phenotypes (leaf shape) and susceptibility to beetles as follows:

- Plant A has smooth-edged leaves and is susceptible to beetles. It has a presence of siRNA 1, which contributes to resistance against beetles. However, the absence of siRNA 2 and siRNA 3 makes it susceptible to beetle attacks. Therefore, the absence of siRNA 2 and siRNA 3 seems to be the key factor that leads to susceptibility.
- Plant B has wavy-edged leaves and is also susceptible to beetles. It has the presence of siRNA 1 and siRNA 2, which both contribute to resistance against beetles. However, the absence of siRNA 3 makes it susceptible to beetle attacks. Therefore, the absence of siRNA 3 seems to be the key factor that leads to susceptibility.
- Plant C has smooth-edged leaves with bumps in the center and is resistant to beetles. It has the presence of all three siRNAs (siRNA 1, siRNA 2, and siRNA 3), which collectively provide resistance against beetles. Therefore, the presence of all three siRNAs seems to be the key factor that leads to resistance.

By comparing the presence or absence of siRNAs in each plant and correlating it with their susceptibility or resistance to beetles, we can decipher the connection between the phenotypes and susceptibility to beetles.