Question

Short Essay Question

EXPLAIN the R- gene responsive response in plants against pathogens; include a short discussion of the 2 defense responses

Answer 1

R genes or the resistance genes in the plants mediate resistance to particular virus, bacteria, fungus or other pathogens. The R genes act by producing the proteins that bind directly to the pathogen or by recognizing the alteration of host proteins by the effector. About 100 to 600 R gene homologs are present in the plant immune systems, and the each individual homologue provides resistance to particular virus, bacteria, fungus, or other pathogens. These genes function to stop the spread of growth of the infection further.

For example, the R genes in tomato, i.e. Cf-9 and Cf-4 provide resistance against the fungus mold “Cladosporium fulvum.” The N gene coding for TIR-NB-LPR protein provides resistance to tobamovirus infection in Nicotiana glutinosa.