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Heterotrimeric G‐proteins of a filamentous fungus regulate cell wall composition and susceptibility to a plant PR‐5 protein
Author(s) -
Coca María A.,
Damsz Barbara,
Yun DaeJin,
Hasegawa Paul M.,
Bressan Ray A.,
Narasimhan Meena L.
Publication year - 2000
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2000.00718.x
Subject(s) - heterotrimeric g protein , cell wall , biology , aspergillus nidulans , g protein , microbiology and biotechnology , protein subunit , signal transduction , biochemistry , mutant , gene
Summary Membrane permeabilizing plant defensive proteins first encounter the fungal cell wall that can harbor specific components that facilitate or prevent access to the plasma membrane. However, signal transduction pathways controlling cell wall composition in filamentous fungi are largely unknown. We report here that the deposition of cell wall constituents that block the action of osmotin (PR‐5), an antifungal plant defense protein, against Aspergillus nidulans requires the activity of a heterotrimeric G‐protein mediated signaling pathway. The guanidine nucleotide GDPβS, that locks G‐proteins in a GDP‐bound inactive form, inhibits osmotin‐induced conidial lysis. A dominant interfering mutation in FadA, the α‐subunit of a heterotrimeric G‐protein, confers resistance to osmotin. A deletion mutation in SfaD, the β‐subunit of a heterotrimeric G‐protein also increases osmotin resistance. Aspergillus nidulans strains bearing these mutations also have increased tolerance to SDS, reduced cell wall porosity and increased chitin content in the cell wall.