CmpacC regulates mycoparasitism, oxalate degradation and antifungal activity in the mycoparasitic fungus Coniothyrium minitans

Abstract

The PacC/Rim101 pH-responsive transcription factor is an important pathogenicity element for many plant-pathogenic fungi. In this study, we investigated the roles of a PacC homologue, CmpacC, in the mycoparasitic fungus Coniothyrium minitans. CmpacC was confirmed to have the transcriptional activation activity by the transcriptional activation test in Saccharomyces cerevisiae. Disruption of CmpacC resulted in impaired fungal responses to ambient pH. Compared to the wild-type, the CmpacC-disruption mutant ΔCmpacC-29 was significantly suppressed for activities of chitinase and β-1,3-glucanase at pH 5 and 7, consistent with reduced expression levels of Cmch1 and Cmg1 coding for the two enzymes respectively. However, the mutant displayed acidity-mimicking phenotypes such as improved oxalate degradation and increased antifungal activity at pH 6 or higher. Improved efficacy in oxalate degradation by ΔCmpacC-29 was consistent with the enhanced expression level of Cmoxdc1 coding for oxalate decarboxylase. CmpacC transcriptional activation of Cmch1 and Cmg1 and repression of Cmoxdc1 were verified by the presence of the PacC/Rim101 consensus binding-motifs in gene promoter regions and by the promoter DNA-binding assays. This study suggests that CmpacC plays an activator role in regulation of C. minitans mycoparasitism, whereas plays a repressor role in regulation of oxalate degradation and possibly antifungal activity of C. minitans.

A HOPS protein, CmVps39, is required for vacuolar morphology, autophagy, growth, conidiogenesis and mycoparasitic functions of Coniothyrium minitans

“…C. minitans is able to grow under a wide range of ambient pH conditions, and recent studies showed that C. minitans can adjust ambient pH via the PacC system to coordinate antibiosis and parasitism. Under low pH conditions, C. minitans produces antifungal substances, while with increased ambient pH, C. minitans secretes fungal cell wall degrading enzymes (Zeng et al ., 2014; Lou et al ., ). It is likely that CmVps39 is involved in the parasitism via the PacC system, and at least partially dependent on the PacC system.…”

“…The mRNA expression of Cmg1 increased in presence of the ground sclerotia of S. sclerotiorum and during parasitic interaction with S. sclerotiorum , indicating that β‐1,3‐glucanase may play important roles in the parasitic process (Giczey et al ., ). Recent research revealed that degradation of oxalic acid, an essential pathogenicity factor of S. sclerotiorum , regulated mycoparasitism and antibiosis of C. minitans against S. sclerotiorum , in which a zinc finger transcription factor pacC homologue, CmPacC, plays an important regulating role (Zeng et al ., ; Lou et al ., ). The parasitism of C. minitans is likely very complicated, and shares some signal transduction pathways with conidiation (Muthumeenakshi et al ., ).…”

Carbendazim sensitivity in populations of Colletotrichum gloeosporioides complex infecting strawberry and yams in Hubei Province of China

“…Representative isolates of different resistant phenotypes and Colletotrichum species were selected for sequencing of their β-tubulin 2 (TUB2) genes. The mycelia of Colletotrichum isolates were obtained by using a previously published protocol (Lou et al 2015). The mycelia of each isolate were ground to a fine powder in liquid nitrogen with a mortar and pestle.…”

The pH regulator PacC: a host‐dependent virulence factor in Botrytis cinerea

“…PacC has been shown to regulate fungal virulence towards mammalian, plant, insect and fungal hosts (Cornet and Gaillardin, ; Rollins, ; Kim et al, ; Alkan et al, , ; Landraud et al, ; Zhang et al, ; Huang et al ., 2015; Lou et al, ). In most cases, the absence or reduced production of PacC leads to a partial to total absence of pathogenicity, but increased virulence has also been reported in Fusarium species (Caracuel et al, ; Merhej et al, ).…”

“…During the last decade, numerous studies have confirmed that this pH signalling pathway is specific and conserved throughout the fungal kingdom. The construction and study of PacC/Rim101 deletion strains in multiple fungal species have revealed that this regulator is required for virulence in human, insect, fungus and plant pathogens (for review, see Alkan et al, ; Landraud et al, ; Bertuzzi et al, ; Cornet and Gaillardin, ; Huang et al ., ; Ost et al, ; Lou et al, ; Luo et al, ). In most cases, PacC plays a role in enzyme and metabolite production and/or fungal cell wall remodelling that are required in the infectious process.…”