Abstract

We used metabarcoding of ITS 1 and 2 to compare the mycobiome of Norwegian spring wheat seed lots of two commonly grown spring wheat varieties (Mirakel and Zebra) harvested in 2016 and 2017. The seed lots varied in germination and were grouped according to high and low germination (≥90% and <90% germinated seeds, respectively) determined by the ISTA germination method. In addition, the percentage of each seed lot infested by the most important wheat pathogens (Microdochium spp., Fusarium spp., and Parastagonospora nodorum) was determined using a plate-out test on PDA, and species-specific qPCR was used to quantify the amount of DNA of F. avenaceum, F. culmorum, F. graminearum, F. poae, M. majus, M. nivale, and P. nodorum. Our study indicated that the presence of Microdochium was most associated with poor germination (which is as expected), while P. nodorum; although present at relatively high levels, apparently had limited impact on germination. Among the species quantified by qPCR, M. majus was the most abundant, F. avenaceum was detected at low levels, whereas the other fusaria were barely detected. Metabarcoding data indicated a negative association between the presence of the fungal genus Neoascochyta and germination, while Pyrenophora and Alternaria species appeared positively associated with germination. Our results indicated some co-existence patterns between fungal species, including both pathogenic and non-pathogenic species, with some species combinations associated with the germination potential of wheat seed.