Open AccessRho1 has distinct functions in morphogenesis, cell wall biosynthesis and virulence of Fusarium oxysporum
Author(s) -
MartínezRocha Ana Lilia,
Roncero M. Isabel G.,
LópezRamirez Adriana,
Mariné Marçal,
Guarro Josep,
MartínezCadena Guadalupe,
Di Pietro Antonio
Publication year - 2008
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2008.01130.x
Subject(s) - biology , virulence , morphogenesis , fusarium oxysporum , microbiology and biotechnology , gene , botany , genetics
Summary Rho‐type GTPases regulate polarized growth in yeast by reorganization of the actin cytoskeleton and through signalling pathways that control the expression of cell wall biosynthetic genes. We report the cloning and functional analysis of rho1 from Fusarium oxysporum , a soilborne fungal pathogen causing vascular wilt on plants and opportunistic infections in humans. F. oxysporum strains carrying either a Δ rho1 loss‐of‐function mutation or a rho1 G14V gain‐of‐function allele were viable, but displayed a severely restricted colony phenotype which was partially relieved by the osmotic stabilizer sorbitol, indicating structural alterations in the cell wall. Consistent with this hypothesis, Δ rho1 strains showed increased resistance to cell wall‐degrading enzymes and staining with Calcofluor white, as well as changes in chitin and glucan synthase gene expression and enzymatic activity. Re‐introduction of a functional rho1 allele into the Δ rho1 mutant fully restored the wild‐type phenotype. The Δ rho1 strain had dramatically reduced virulence on tomato plants, but was as virulent as the wild type on immunodepressed mice. Thus, Rho1 plays a key role during fungal infection of plants, but not of mammalian hosts.