Question

5) The model plant Arabidopsis is able to resist bacterial infection in part through expression of the RES1 gene after infection. a) Suggest a phenotype for a res1 mutation. b) What tool could you create that would allow you to visualize the temporal pattern of RES1 gene expression after infection? c) Too much RES1 protein is toxic to the plant. After the bacterial infection is eliminated, RES1 gene expression rapidly decreases. Draw a schematic diagram of a circuit that would regulate RES1 through a negative feedback loop, with RES1 limiting its own expression. infection RES1 expression -2 0 2 4 6 8 10 12 14 16 18 Days post infection d) Using the plants you obtained in a and b, design an experiment to determine whether RES1 is limiting its own expression via a negative feedback loop.

Answer 1

a. It is given that RES1 is involved in providing resistance to bacterial infection. So, loss of the RES1 function results in sensitivity to bacterial infection.

b. To examine the temporal and spatial expression pattern of RES1, clone the RES1 gene under a reporter such as GFP/RFP. Analyze the marker gene expression pattern using a fluorescent microscope.
We can create transcriptional or translational fusions.

c. See the image

d. Cross the promoter fusion of RES1 into res-1 mutant background and analyze the reporter expression.
If RES1 is exhibiting auto-feedback inhibition, the RES1 promoter marker expression would be elevated in the res-1 mutant background.

Bacterial infection -----> RES1 expression -------> Downstream target gene ------> Resistance

Please provide a POSITIVE RATING. Thank you