Discovery of Two Novel Phthalide Phytotoxins from the Wheat Tan Spot Fungal Pathogen .

The Dothideomycete fungal pathogen (Ptr) is the causal agent of the tan spot disease of wheat. The proteinaceous necrotrophic effectors ToxA and ToxB are well characterized. A nonproteinaceous effector called ToxC has also been partially characterized.

A New Haplotype in the Wheat Fungal Pathogen .

The necrotrophic effector ToxA is a well-studied virulence factor produced by several fungal necrotrophs. Initially cloned from the wheat tan spot pathogen in 1996, was found almost a decade later in another fungal pathogen, and its sister species, . In 2018, ToxA was detected in a third wheat fungal pathogenic species, , which causes spot blotch disease.

Profiling the Pyrenophora tritici-repentis secretome: The Pf2 transcription factor regulates the secretion of the effector proteins ToxA and ToxB.

The global wheat disease tan spot is caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) which secretes necrotrophic effectors to facilitate host plant colonization. We previously reported a role of the Zn Cys binuclear cluster transcription factor Pf2 in the regulation of the Ptr effector ToxA. Here, we show that Pf2 is also a positive regulator of ToxB, via targeted deletion of PtrPf2 which resulted in reduced ToxB expression and defects in conidiation and pathogenicity.

An international wheat diversity panel reveals novel sources of genetic resistance to tan spot in Australia.

Novel sources of genetic resistance to tan spot in Australia have been discovered using one-step GWAS and genomic prediction models that accounts for additive and non-additive genetic variation. Tan spot is a foliar disease in wheat caused by the fungal pathogen Pyrenophora tritici-repentis (Ptr) and has been reported to generate up to 50% yield losses under favourable disease conditions. Although farming management practices are available to reduce disease, the most economically sustainable approach is establishing genetic resistance through plant breeding.

A Revised Nomenclature for Haplotypes Across Multiple Fungal Species.

ToxA is one of the most studied proteinaceous necrotrophic effectors produced by plant pathogens. It has been identified in four pathogens (, , [formerly f. sp.

A Race Profile of Tan Spot in Australia Reveals Race 2 Isolates Harboring .

Tan spot disease is caused by (Ptr), one of the major necrotrophic fungal pathogens that affects wheat crops globally. Extensive research has shown that the necrotrophic fungal effectors ToxA, ToxB, and ToxC underlie the genetic interactions of Ptr race classification. ToxA and ToxB are both small proteins secreted during infection; however, the structure of ToxC remains unknown.

A global pangenome for the wheat fungal pathogen and prediction of effector protein structural homology.

The adaptive potential of plant fungal pathogens is largely governed by the gene content of a species, consisting of core and accessory genes across the pathogen isolate repertoire. To approximate the complete gene repertoire of a globally significant crop fungal pathogen, a pan genomic analysis was undertaken for (Ptr), the causal agent of tan (or yellow) spot disease in wheat. In this study, 15 new Ptr genomes were sequenced, assembled and annotated, including isolates from three races not previously sequenced.

A Conserved Hypothetical Gene Is Required but Not Sufficient for Ptr ToxC Production in .

The fungus causes tan spot, an important foliar disease of wheat worldwide. The fungal pathogen produces three necrotrophic effectors, namely Ptr ToxA, Ptr ToxB, and Ptr ToxC to induce necrosis or chlorosis in wheat. Both Ptr ToxA and Ptr ToxB are proteins, and their encoding genes have been cloned.

The first genome assembly of fungal pathogen Pyrenophora tritici-repentis race 1 isolate using Oxford Nanopore MinION sequencing.

Objectives: The assembly of fungal genomes using short-reads is challenged by long repetitive and low GC regions. However, long-read sequencing technologies, such as PacBio and Oxford Nanopore, are able to overcome many problematic regions, thereby providing an opportunity to improve fragmented genome assemblies derived from short reads only. Here, a necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) isolate 134 (Ptr134), which causes tan spot disease on wheat, was sequenced on a MinION using Oxford Nanopore Technologies (ONT), to improve on a previous Illumina short-read genome assembly and provide a more complete genome resource for pan-genomic analyses of Ptr.

Genetic characterization of adult-plant resistance to tan spot (syn, yellow spot) in wheat.

QTL mapping identified key genomic regions associated with adult-plant resistance to tan spot, which are effective even in the presence of the sensitivity gene Tsn1, thus serving as a new genetic solution to develop disease-resistant wheat cultivars. Improving resistance to tan spot (Pyrenophora tritici-repentis; Ptr) in wheat by eliminating race-specific susceptibility genes is a common breeding approach worldwide. The potential to exploit variation in quantitative forms of resistance, such as adult-plant resistance (APR), offers an alternative approach that could lead to broad-spectrum protection.

A genome-wide genetic linkage map and reference quality genome sequence for a new race in the wheat pathogen Pyrenophora tritici-repentis.

Pyrenophora tritici-repentis is an ascomycete fungus that causes tan spot of wheat. The disease has a worldwide distribution and can cause significant yield and quality losses in wheat production. The fungal pathogen is homothallic in nature, which means it can undergo sexual reproduction by selfing to produce pseudothecia on wheat stubble for seasonal survival.

PacBio genome sequencing reveals new insights into the genomic organisation of the multi-copy ToxB gene of the wheat fungal pathogen Pyrenophora tritici-repentis.

Background: Necrotrophic effector proteins secreted by fungal pathogens are important virulence factors that mediate the development of disease in wheat. Pyrenophora tritici-repentis (Ptr), the causal agent of wheat tan spot, has a race structure dependent on the combination of effectors. In Ptr, ToxA and ToxB are known proteinaceous effectors responsible for necrosis and chlorosis respectively.

Expansion and Conservation of Biosynthetic Gene Clusters in Pathogenic spp.

is a fungal genus responsible for a number of major cereal diseases. Although fungi produce many specialised or secondary metabolites for defence and interacting with the surrounding environment, the repertoire of specialised metabolites (SM) within pathogenic species remains mostly uncharted. In this study, an in-depth comparative analysis of the f.

Hierarchical clustering of MS/MS spectra from the firefly metabolome identifies new lucibufagin compounds.

Metabolite identification is the greatest challenge when analysing metabolomics data, as only a small proportion of metabolite reference standards exist. Clustering MS/MS spectra is a common method to identify similar compounds, however interrogation of underlying signature fragmentation patterns within clusters can be problematic. Previously published high-resolution LC-MS/MS data from the bioluminescent beetle (Photinus pyralis) provided an opportunity to mine new specialized metabolites in the lucibufagin class, compounds important for defense against predation.

Genetic analysis of wheat sensitivity to the ToxB fungal effector from Pyrenophora tritici-repentis, the causal agent of tan spot.

Genetic mapping of sensitivity to the Pyrenophora tritici-repentis effector ToxB allowed development of a diagnostic genetic marker, and investigation of wheat pedigrees allowed transmission of sensitive alleles to be tracked. Tan spot, caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis, is a major disease of wheat (Triticum aestivum). Secretion of the P.

The identification and deletion of the polyketide synthase-nonribosomal peptide synthase gene responsible for the production of the phytotoxic triticone A/B in the wheat fungal pathogen Pyrenophora tritici-repentis.

The economically important necrotrophic fungal pathogen, Pyrenophora tritici-repentis (Ptr), causes tan spot of wheat, a disease typified by foliar necrosis and chlorosis. The culture filtrate of an Australian Ptr isolate, M4, possesses phytotoxic activity and plant bioassay guided discovery led to the purification of necrosis inducing toxins called triticone A and B. High-resolution LC-MS/MS analysis of the culture filtrate identified an additional 37 triticone-like compounds.

A new PacBio genome sequence of an Australian Pyrenophora tritici-repentis race 1 isolate.

Objectives: The necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) is the causal agent of tan spot a major disease of wheat. We have generated a new genome resource for an Australian Ptr race 1 isolate V1 to support comparative 'omics analyses. In particular, the V1 PacBio Biosciences long-read sequence assembly was generated to confirm the stability of large-scale genome rearrangements of the Australian race 1 isolate M4 when compared to the North American race 1 isolate Pt-1C-BFP.

Heterologous Expression of the Effector Proteins ToxA and ToxB, and the Prevalence of Effector Sensitivity in Australian Cereal Crops.

Here, we evaluate the expression of the proteinaceous effectors ToxA and ToxB, produced by the necrotrophic fungal pathogen , which confer tan spot disease susceptibility on wheat. These necrotrophic effectors were expressed in two heterologous systems: and . The SHuffle system was demonstrated to be superior to in generating high-levels of recombinant proteins that were soluble and stable.

Exploration of wheat and pathogen transcriptomes during tan spot infection.

Objectives: The fungus Pyrenophora tritici-repentis is the causal agent of tan spot, a major disease of wheat (Triticum aestivum). Here, we used RNA sequencing to generate transcriptional datasets for both the host and pathogen during infection and during in vitro pathogen growth stages.

Data Description: To capture gene expression during wheat infection with the P.

Proteomics of the wheat tan spot pathogen Pyrenophora tritici-repentis.

Objectives: The fungus Pyrenophora tritici-repentis is a major pathogen of wheat worldwide, causing the leaf spotting disease tan spot. To best inform approaches for plant genetic resistance, an understanding of the biology and pathogenicity mechanisms of this fungal pathogen is essential. Here, intracellular and extracellular proteins of P.

Genomic distribution of a novel Pyrenophora tritici-repentis ToxA insertion element.

The ToxA effector is a major virulence gene of Pyrenophora tritici-repentis (Ptr), a necrotrophic fungus and the causal agent of tan spot disease of wheat. ToxA and co-located genes are believed to be the result of a recent horizontally transferred highly conserved 14kb region a major pathogenic event for Ptr. Since this event, monitoring isolates for pathogenic changes has become important to help understand the underlying mechanisms in play.

Real-Time PCR for Diagnosing and Quantifying Co-infection by Two Globally Distributed Fungal Pathogens of Wheat.

Co-infections - invasions of a host-plant by multiple pathogen species or strains - are common, and are thought to have consequences for pathogen ecology and evolution. Despite their apparent significance, co-infections have received limited attention; in part due to lack of suitable quantitative tools for monitoring of co-infecting pathogens. Here, we report on a duplex real-time PCR assay that simultaneously distinguishes and quantifies co-infections by two globally important fungal pathogens of wheat: and .