Fungicide treatments are common control strategies used to manage fungal pathogens in agricultural fields, however, effects of treatments on the composition of total fungal communities, including non-target fungi, in the phyllosphere is not well known. Yellow rust (Puccinia striiformis) is a common disease in wheat and within the last decade, new aggressive strains of yellow rust has caused severe epidemics that lead to substantial yield losses. This study explored the community composition of target versus non-target fungi in yellow rust infected wheat as affected by treatment timing and dose of three fungicides. The fungal composition in bulked leaf samples and individual leaves was studied by deep amplicon 454 pyrosequencing targeting the internal transcribed spacer-1 (ITS1) region of the ribosomal DNA. Amount of yellow rust in individual samples was quantified by qPCR. Pyrosequencing resulted in 179,081 sequences from bulked leaf samples and 91,182 sequences from individual leaves excluding low quality sequences and singletons; in total 270,263 sequences clustering into 1operational taxonomic units (OTUs). Three different treatment regimens with two of the fungicides resulted in an amount of yellow rust below detection level. Fungal diversity was stable across treatments whereas the relative abundance of individual OTUs was affected by fungicide treatment.
Functions and Ecology of the Plant Microbiome: 28th New Phytologist Symposium, 2012, p. 48-48