Dysfunction of Ras-GAP protein AfgapA contributes to hypoxia fitness in Aspergillus fumigatus

Bian, Cai; Kusuya, Yoko; Hagiwara, Daisuke; Ban, Sayaka; Lu, Yu; Nagayama, Masaki; Takahashi, Hiroki

doi:10.1007/s00294-022-01249-9

Cited by 1 publication

(1 citation statement)

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“…The gapA protein acts as a negative regulator of RasA in A. nidulans and is involved in hyphal growth and asexual morphogenesis (Harispe et al., 2008 ). In Aspergillus fumigatus , AfgapA governs hypoxia fitness, hypervirulence and conidial pigmentation (Bian et al., 2022 ). In Fusarium graminearum , the absence of RAS2 results in defective perithecia formation; however, loss of RAS2 does not impact the virulence of F. graminearum to maize and wheat seedlings (Bluhm et al., 2007 ).…”

Section: Introductionmentioning

confidence: 99%

The Ras GTPase‐activating protein UvGap1 orchestrates conidiogenesis and pathogenesis in the rice false smut fungus Ustilaginoidea virens

Cao,

Gong,

et al. 2024

Molecular Plant Pathology

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Ras GTPase‐activating proteins (Ras GAPs) act as negative regulators for Ras proteins and are involved in various signalling processes that influence cellular functions. Here, the function of four Ras GAPs, UvGap1 to UvGap4, was identified and analysed in Ustilaginoidea virens, the causal agent of rice false smut disease. Disruption of UvGAP1 or UvGAP2 resulted in reduced mycelial growth and an increased percentage of larger or dumbbell‐shaped conidia. Notably, the mutant ΔUvgap1 completely lost its pathogenicity. Compared to the wild‐type strain, the mutants ΔUvgap1, ΔUvgap2 and ΔUvgap3 exhibited reduced tolerance to H2O2 oxidative stress. In particular, the ΔUvgap1 mutant was barely able to grow on the H2O2 plate, and UvGAP1 was found to influence the expression level of genes involved in reactive oxygen species synthesis and scavenging. The intracellular cAMP level in the ΔUvgap1 mutant was elevated, as UvGap1 plays an important role in maintaining the intracellular cAMP level by affecting the expression of phosphodiesterases, which are linked to cAMP degradation in U. virens. In a yeast two‐hybrid assay, UvRas1 and UvRasGef (Ras guanyl nucleotide exchange factor) physically interacted with UvGap1. UvRas2 was identified as an interacting partner of UvGap1 through a bimolecular fluorescence complementation assay and affinity capture‐mass spectrometry analysis. Taken together, these findings suggest that the UvGAP1‐mediated Ras pathway is essential for the development and pathogenicity of U. virens.

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Section: Introductionmentioning

confidence: 99%