Plant Pathology practical

Question 1

What is the role of salicylic acid (SA) in systemic acquired resistance (SAR)?

Answer 1

SA is essential for inducing SAR and PR protein expression. Without SA, plants are more susceptible to pathogen invasion.

Question 2

What are nahG mutant plants?

Answer 2

NahG mutants are genetically modified Arabidopsis plants that cannot accumulate SA due to the nahG gene encoding salicylate hydroxylase, which breaks down SA.

Question 3

How does the nahG mutation affect SAR?

Answer 3

NahG mutants lack the ability to accumulate SA, resulting in the failure to develop SAR and making them more vulnerable to infection compared to wild-type plants.

Question 4

What is the expected result for wild-type plants sprayed with SA?

Answer 4

Wild-type plants sprayed with SA show reduced infection and increased PR protein activity, demonstrating effective SAR.

Question 5

What is the expected result for nahG mutant plants sprayed with SA?

Answer 5

NahG mutants sprayed with SA are unable to develop SAR despite treatment, as they cannot accumulate SA.

Question 6

What is measured in the peroxidase activity assay?

Answer 6

Peroxidase activity is measured in treated and untreated plants to evaluate the response, indicating the activation of SAR.

Question 7

What is the significance of this experiment on SAR?

Answer 7

The experiment highlights the critical role of SA in plant immunity and the potential applications of SA or its analogs in crop protection.