PFP1 , a Gene Encoding an Epc-N Domain-Containing Protein, Is Essential for Pathogenicity of the Barley Pathogen Rhynchosporium commune

Abstract

Scald caused by Rhynchosporium commune is an important foliar disease of barley. Insertion mutagenesis of R. commune generated a nonpathogenic fungal mutant which carries the inserted plasmid in the upstream region of a gene named PFP1. The characteristic feature of the gene product is an Epc-N domain. This motif is also found in homologous proteins shown to be components of histone acetyltransferase (HAT) complexes of fungi and animals. Therefore, PFP1 is suggested to be the subunit of a HAT complex in R. commune with an essential role in the epigenetic control of fungal pathogenicity. Targeted PFP1 disruption also yielded nonpathogenic mutants which showed wild-type-like growth ex planta, except for the occurrence of hyphal swellings. Complementation of the deletion mutants with the wild-type gene reestablished pathogenicity and suppressed the hyphal swellings. However, despite wild-type-level PFP1 expression, the complementation mutants did not reach wild-type-level virulence. This indicates that the function of the protein complex and, thus, fungal virulence are influenced by a position-affected long-range control of PFP1 expression.

Comparative genomics to explore phylogenetic relationship, cryptic sexual potential and host specificity of Rhynchosporium species on grasses

“…Relative fungal biomass and fungal gene expression during pathogenesis were quantified by qPCR with DNA as template and by qRT-PCR with cDNA as template using the efficiency calibrated model [119] as described previously [105, 161]. For qPCR the fungal target gene GPD was quantified using the primers GPDRT2s and GPDRT2as, the barley reference gene TSP (GenBank accession no.…”

“…Constructs for the disruption of RcSP genes were generated by fusion PCR [161, 162] and deletion mutants were obtained through split-marker recombination by replacing the RcSP genes with a hph resistance cassette [121]. To this end, 1000 bp of RcsP 5′ and 3′ flanking sequence were amplified in a first step using the primer pairs fusion1_s/fusion2_as and fusion3_s/fusion4_as, respectively, (Additional file 12: Table S7) and genomic DNA as template.…”

“…In the third step, the split-marker constructs overlapping in the hph gene by 50 bp were generated using the primer pairs fusionA_s/HPH-r and HPH50-f/fusion-as. Fungal transformation and mutant selection was described previously [105, 161, 164]. Successful deletion of the genes RcSP1, RcSP2, RcSP5 and RcSP6 was analyzed using the primer pairs RcSPn_dt_s/RcSPn_dt_as, whereas deletion of RcSP3 and RcSP9 was shown with the primer pairs RcSPn-seq-s/RcSPn-seq-as.…”

Modify the Histone to Win the Battle: Chromatin Dynamics in Plant–Pathogen Interactions

“…In F. fujikuroi , a rice pathogen, the HDACs FfHda1 and FfHda2 have been shown to regulate the production of secondary metabolites and virulence ( Studt et al, 2013 ); HDAC activity also seems to regulate infectious growth in fungi from other genera, such as the rice pathogen Magnaporte oryzae , where mutants in components of the HDAC complex proteins TIG1, SET3, SNT1 , and HOS2 present defects in conidiogenesis, plant invasion, pathogenicity, and an increased sensitivity to ROS ( Ding et al, 2010 ). Likewise, HDAC activity regulates the virulence in Cochliobolus carbonum on maize and the infection capacity of Rhynchosporium commune on barley, suggesting an importance of histone acetylation dynamics in the adaptation of fungi from diverse phyla to a pathogenic lifestyle ( Baidyaroy et al, 2001 ; Siersleben et al, 2014 ).…”

The structure of the Pfp1 protease from the hyperthermophilic archaeonThermococcus thioreducensin two crystal forms

“…Research has defined Pfp1 and its homologs as belonging to the DJ-1/ThiJ/Pfp1 superfamily, all members of which possess cysteine residues in a unique 'nucleophilic elbow' (Ollis et al, 1992;Abdallah et al, 2007;Wei et al, 2007). More recently, the E. coli YhbO protein (Abdallah et al, 2007), B. subtilis protein 18, a protease from Rhynchosporin commune (a fungal pathogen of barley; Siersleben et al, 2014) and a gene product in Leishmania major (Eschenlauer et al, 2006) have been identified as homologs of Pfp1. Most intriguingly, some of these homologs are parts of, or are related to, heat-shock proteins and proteasomes (Ward et al, 2002).…”