FSR1 is essential for virulence and female fertility in Fusarium verticillioides and F. graminearum.
Fusarium verticillioides (teleomorph Gibberella moniliformis) and F. graminearum (teleomorph G. zeae) are well known to cause devastating diseases on cereal crops. Despite their importance, our understanding of the molecular mechanisms involved in these host-pathogen interactions is limited. The FSR1 locus in F. verticillioides was identified by screening REMI mutants for loss of virulence in maize stalk rot inoculation studies. FSR1 encodes an 823-codon open reading frame interrupted by two introns. The Fsr1 protein shares 60% sequence identity with the Sordaria macrospora Pro11, a multimodular protein with four putative protein-protein binding domains (caveolin-binding domain, coiled-coil structure, calmodulin-binding motif, and seven-WD40 repeats), which plays a regulatory role in cell differentiation and ascocarp development. Our data demonstrate that FSR1 is essential for female fertility and virulence in F. verticillioides. Significantly, targeted disruption of the FSR1 ortholog in F. graminearum (FgFSR1) reduced virulence on barley and deterred perithecia formation. Cross-complementation experiments demonstrated that the gene function is conserved in the two Fusarium species. FSR1 is expressed constitutively, and we hypothesize that Fsr1 regulates virulence by acting as a scaffold for a signal transduction pathway. A survey of available genome databases indicates Fsr1 homologs are present in a number of filamentous fungi and animal systems but not in budding yeast or plants. A maximum likelihood analysis of this gene family reveals well-supported monophyletic clades associated with fungi and animals.
Shim
Won-Bo
WB
Department of Plant Pathology and Microbiology, Program for the Biology of Filamentous Fungi, Texas A&M University, College Station 77843-2132, USA. wbshim@tamu.edu
Sagaram
Uma Shankar
US
Choi
Yoon-E
YE
So
Jinny
J
Wilkinson
Heather H
HH
Lee
Yin-Won
YW
D000595:Amino Acid Sequence; D005298:Fertility / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D005670:Fusarium / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D015966:Gene Expression Regulation, Fungal; D001467:Hordeum / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D014774:Virulence; D003313:Zea mays / Q000382:microbiology
D005656:Fungal Proteins