Diapason : diagnostic of gray leaf spot by digital PCR [P4.2-070]

Abstract

Fungal pathogens are a major threat to plants, whether they are cultivated for food or for recreational areas. Pyricularia oryzae is a fungal pathogen infecting more than 50 grasses and is particularly known on major food species such as rice and wheat. This fungus is also known on turf grass as the causal agent of gray leaf spot. As of 2016, in France, the disease is present on the lawns of professional Football stadiums. Gray leaf spot is a cyclic disease, difficult to eradicate once establish on the field. Indeed, p ineffective if the application is too late. To manage efficiently the gray leaf spot disease on their sport fields, turf managers require an early and quick diagnostic during the first cycle of the disease. The objective of the Diapason project (partnership UMR PHIM / IAGE company) is thus to develop an early diagnostic method based on digital PCR. The diagnostic was first validated in vitro on pure strains of fungal pathogens and in vivo on samples produced under controlled conditions by artificial inoculations. The application of the diagnostic on sport fields was then done on grass clippings, sampled on a Football stadium presenting symptoms of the disease. An improvement of the diagnostic is under progress (i) to discriminate the P. oryzae lineage affecting turfgrass, rice and wheat and (ii) to extend the diagnostic to other turfgrass diseases identified in stadium, golf courses, and race courses