MOD-D, a Gα Subunit of the Fungus Podospora anserina, Is Involved in Both Regulation of Development and Vegetative Incompatibility

Abstract

Cell death via vegetative incompatibility is widespread in fungi but molecular mechanism and biological function of the process are poorly understood. One way to investigate this phenomenon was to study genes named mod that modified incompatibility reaction. In this study, we cloned the mod-D gene that encodes a Gα protein. The mod-D mutant strains present developmental defects. Previously, we showed that the mod-E gene encodes an HSP90. The mod-E1 mutation suppresses both vegetative incompatibility and developmental defects due to the mod-D mutation. Moreover, we isolated the PaAC gene, which encodes an adenylate cyclase, as a partial suppressor of the mod-D1 mutation. Our previous results showed that the molecular mechanisms involved in vegetative incompatibility and developmental pathways are connected, suggesting that vegetative incompatibility may result from disorders in some developmental steps. Our new result corroborates the involvement of mod genes in signal transduction pathways. As expected, we showed that an increase in the cAMP level is able to suppress the defects in vegetative growth due to the mod-D1 mutation. However, cAMP increase has no influence on the suppressor effect of the mod-D1 mutation on vegetative incompatibility, suggesting that this suppressor effect is independent of the cAMP pathway.

Plants interfere with non-self recognition of a phytopathogenic fungus via proline accumulation to facilitate mycovirus transmission

“…Conversely, strains harboring different alleles are incompatible and belong to different VCGs 1 , 9 , 13 . Genes involved in the self/non-self recognition reaction encode heterotrimeric guanine nucleotide-binding proteins (G proteins), proteins involved in generation and scavenging of reactive oxygen species (ROS), and proteins containing HET domains, nucleotide oligomerization domain-like receptors, and cell wall remodeling checkpoint regulators 5 , 11 , 12 , 14 , 15 . Fundamentally, the self/non-self reaction functions akin to a rudimentary innate immune system, restricting the transmission of deleterious factors, including mycoviruses, between fungal strains, and thereby enhancing organismal fitness in natural environments 11 .…”