Correct option is D
The correct answer is: (4) Degradation of guardee protein can activate the defense response.
Explanation:
The guardee protein plays a role in the plant's defense response during pathogen interactions. Guardee proteins are targeted by certain bacterial effectors, and their degradation can trigger the activation of plant defense mechanisms. This process is a part of the plant's immune response, where the degradation of guardee proteins (which are typically associated with the plant's own defense or cell function) leads to the recognition of the pathogen, activating a defense response even in plants that do not have the cognate resistance (R) proteins.
Additional Knowledge:
Bacterial proteins guarding host components (option 1) is not the primary function of guardee proteins. Guardee proteins are typically plant proteins that are targeted by bacterial effectors.
Secretion via type III secretion system (option 2) is a mechanism by which bacterial effectors are introduced into plant cells, but guardee proteins themselves are plant proteins, not bacterial ones.
Imparts disease resistance in plants lacking cognate R protein (option 3) is not correct. Guardee proteins themselves are not responsible for imparting resistance in plants but rather play a role in the activation of defense mechanisms when degraded.
