Figure 5.

The cell wall mutant mur1-1 has a relatively subtle nonhost phenotype compared with pen1 mutants. (A and B) pen1-1; (C) wild type. (A) pen1-1 mutants are characterized by an increased incidence of fungal penetration, as evidenced by the presence of haustoria (arrows). Note the callose encasement of both the haustoria and infected cells. (B) The most frequent response to nonhost infection in pen1-1 mutants is to outline the infected cell with callose. (C) On Bgh infection, wild-type plants generally deposit a cell wall apposition or papilla at the site of attempted penetration. (D) Percent Bgh penetration in mur1-1 and pen1-1 mutants. Bar in A is 10 μm; other panels are to scale.