Modifies a noun

• strain: Our aims are to map the signaling pathways of importance in control of differentiation and to compare the responsiveness of virulent and avirulent strains.

• mutant: Studies are currently underway to develop and evaluate biological control agents for this disease using avirulent mutants of the pathogen itself.

• pathogen: We concluded that, to resistant cultivar of plants, the behavior of virulent and avirulent pathogen was similar except their extent being affection.