TheFusarium oxysporumcell wall proteome under adhesion‐inducing conditions

Abstract

Fusarium oxysporum is a soilborne fungus that causes vascular wilt disease on a wide range of crops. During initial stages of infection, fungal hyphae attach firmly to roots, penetrate the cortex and colonize xylem vessels. The mechanisms underlying root attachment are poorly understood, although it was previously shown that this process depends on Fmk1, a mitogen-activated protein kinase orthologous to the mating/filamentation mitogen-activated protein kinases Fus3/Kss1 in yeast. We investigated the hypothesis that root adhesion is mediated by fungal cell wall proteins (CWPs). To characterize the cell wall subproteome of F. oxysporum, we performed LC-MS/MS analysis of tryptic digests of purified cell walls obtained from adhesion-inducing conditions, identifying a total of 174 proteins, 19 of which contain a predicted signal peptide and 10 of which have a predicted glycosylphosphatidyl-inositol motif. 2-D DIGE was used to compare four different fractions of CWPs extracted from hyphae of the wild-type strain and the Deltafmk1 mutant. We detected 18 proteins differing significantly in abundance between the two strains. Differential expression of five of these proteins was confirmed by RT-PCR analysis. A significant fraction of the subproteome lacked functional information, highlighting the limitations in the current understanding of CWPs in F. oxysporum.

Genome and Transcriptome Analysis of the Fungal Pathogen Fusarium oxysporum f. sp. cubense Causing Banana Vascular Wilt Disease

“…Deletion of the MAP Kinase gene fmk1 result in impaired root attachment in Fo [11]. Prados-Rosales R et al identified a fraction of proteins involved in attachment of roots from cell wall proteome of Fol, but these proteins lacked functional information [24]. Here, we identified 5 and 6 adhesin genes in Foc1 and Foc4 genomes, respectively,one of which is the counterpart of SOWgp.…”

The Membrane Mucin Msb2 Regulates Invasive Growth and Plant Infection in Fusarium oxysporum

“…In S. cerevisiae, it was suggested that this process involves cleavage of the extracellular Msb2 domain by the glycosylphosphatidylinositol-anchored aspartyl protease Yps1p, a member of the yapsin family (Vadaie et al, 2008). A genome-wide inventory of the predicted glycosylphosphatidyl-inositol-anchored proteins in F. oxysporum detected several aspartic proteases, one of which, FOXG_09428, is a putative ortholog of Yps1p (Prados- Rosales et al, 2009). However, immunoblot analysis of F. oxysporum Msb2 proteins obtained from cellular extracts and from supernatants failed to detect an expected difference in electrophoretic mobility, even after prolonged electrophoresis.…”

Adhesins in Human Fungal Pathogens: Glue with Plenty of Stick

“…However, none of these were identified during mass spectrometric analysis of hyphal walls under adhesion-inducing conditions (125).…”