Diversity ofFusariumspecies isolated from UK forage maize and the population structure ofF. graminearumfrom maize and wheat

Abstract

Pre-harvest contamination of forage maize by mycotoxin producingFusariumspecies was investigated in the UK in 2011 and 2012. A total of 15Fusariumspecies were identified from a collection of 1,761Fusariumisolates recovered from maize stalks and kernels. This study characterized the diversity ofFusariumspecies present in forage maize in the UK. The predominant species detected wereF. graminearum(32.9%) andF. culmorum(34.1%). Along with those species;F. avenacem, F. cerealis, F. equiseti, F. langsethiae, F. napiforme, F. oxysporum, F. poae, F. proliferatum, F. scripi, F. solani, F. subglutinans, F. tricinctumand,F. verticillioideswere occasionally isolated. The trichothecene genotypes forF. graminearumwere determined to be 84.9% deoxynivalenol (DON) and 15.0% nivalenol (NIV) whileF. culmorumisolates were determined to have 24.9% DON and 75.1% NIV genotypes. A Bayesian model-based clustering method with nine variable number of tandem repeat markers was used to evaluate the population genetic structure of 277F. graminearumisolates from the maize and wheat in the UK. There were three genetic clusters detected which were DON in maize, NIV in maize and DON in wheat. There were high admixture probabilities for 14.1% of the isolates in the populations. In conclusion, increased maize production in the UK and the high admixture rates in a significant portion ofF. graminearumpopulations in maize and wheat will contribute to a new pathogen population which will further complicate breeding strategies for tolerance or resistance to this pathogen in both crops.