WA researchers have used DNA screening to establish a co-infection by two fungal species common in wheat.
The species Pyrenophora tritici-repentis (Ptr) and Parastagonospora nodorum (Pan) cause tan spot and septoria nodorum blotch respectively. Scientific identification of these two species has been hampered in the past by the visual similarity of symptoms they cause and difficulties quantifying the levels of the pathogens. The problem exists in wheat-cropping regions globally.
Researchers from Curtin University and the UWA Institute of Agriculture used a recently developed molecular method that simultaneously distinguishes and quantifies, in DNA equivalent, the level of pathogen present.
They used the method to examine the prevalence of co-infection under field conditions, at three widely spaced sites and on three wheat cultivars varying in disease resistance. Co-infection by Ptr and Pan was found to be 94% and Pan DNA was detected only in association with Ptr. Although Ptr and Pan commonly co-infected, Ptr was more abundant during early and mid-season while Pan became as abundant as Ptr when crops reached flowering.
Lead researcher Araz Solman from Curtin’s Centre for Crop and Disease Management in the School of Molecular and Life Sciences, said: “Variations were primarily determined by cultivar, however, Ptr was the more abundant despite differences in cultivar resistance.”
Other researchers were Mark Gibberd and John Hamblin.
Source: Crop and Pasture Science 71(2) 119-127 https://doi.org/10.1071/CP19412
Featured Image: Araz Solman