ea (Pisum sativum L., 2n = 14) is the second most important grain legume in the world after common bean and is an important green vegetable with 14.3 t of dry pea and 19.9 t of green pea produced in 2016 (http://www.fao.org/faostat/). Pea belongs to the Leguminosae (or Fabaceae), which includes cool season grain legumes from the Galegoid clade, such as pea, lentil (Lens culinaris Medik.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.) and tropical grain legumes from the Milletoid clade, such as common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.) and mungbean (Vigna radiata (L.) R. Wilczek). It provides significant ecosystem services: it is a valuable source of dietary proteins, mineral nutrients, complex starch and fibers with demonstrated health benefits 1-4 and its symbiosis with N-fixing soil bacteria reduces the need for applied N fertilizers so mitigating greenhouse gas emissions 5-7. Pea was domesticated ~10,000 years

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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: Pyrenophora tritici-repentis and Parastagonospora nodorum. These fungi share common characteristics and host species, creating a challenge for conventional disease diagnosis and subsequent management strategies. The assay uses uniquely assigned fluorogenic probes to quantify fungal biomass as nucleic acid equivalents. The probes provide highly specific target quantification with accurate discrimination against non-target closely related fungal species and host genes. Quantification of the fungal targets is linear over a wide range (5000–0.5 pg DNA μl-1) with high reproducibility (RSD ≤ 10%). In the presence of host DNA in the assay matrix, fungal biomass can be quantified up to a fungal to wheat DNA ratio of 1 to 200. The utility of the method was demonstrated using field samples of a cultivar sensitive to both pathogens. While visual and culture diagnosis suggested the presence of only one of the pathogen species, the assay revealed not only presence of both co-infecting pathogens (hence enabling asymptomatic detection) but also allowed quantification of relative abundances of the pathogens as a function of disease severity. Thus, the assay provides for accurate diagnosis; it is suitable for high-throughput screening of co-infections in epidemiological studies, and for exploring pathogen–pathogen interactions and dynamics, none of which would be possible with conventional approaches.

The barley net blotch diseases are caused by two fungal species of the Pyrenophora genus. Specifically, spot form net blotch is caused by P. teres f. sp. maculata (Ptm) whereas net form net blotch is caused by P. teres f. sp. teres (Ptt). Ptt and Ptm show high genetic diversity in the field due to intraspecific sexual recombination and hybridisation of the two species although the latter is considered rare. Here we present occurrence of a natural Ptt/Ptm hybrid with azole fungicides resistance and its implication to barley disease management in Australia. We collected and sequenced a hybrid, 3 Ptm and 10 Ptt isolates and performed recombination analyses in the intergenic and whole genome level. Eleven out of 12 chromosomes showed significant (P < 0.05) recombination events in the intergenic regions while variable recombination rate showed significant recombination across all the chromosomes. Locus specific analyses of Cyp51A1 gene showed at least four recombination breakpoints including a point mutation that alter target protein function. This point mutation did not found in Ptt and Ptm collected prior to 2013 and 2017, respectively. Further genotyping of fourteen Ptt, 48 HR Ptm, fifteen Ptm and two P. teres isolates from barley grass using Diversity Arrays Technology markers showed that all HR Ptm isolates were clonal and not clustered with Ptt or Ptm. The result confirms occurrence of natural recombination between Ptt and Ptm in Western Australia and the HR Ptm is likely acquired azole fungicide resistance through recombination and underwent recent rapid selective sweep likely within the last decade. The use of available fungicide resistance management tactics are essential to minimise and restrict further dissemination of these adaptive HR Ptm isolates.