Selection and screening of fungal endophytes against wheat pathogens

Abstract

Tissues of field grown winter wheat ‘AC Morley’ and ‘25R34′ and spring wheat ‘Sumai’ and ‘Scotia’ were collected from Ariss, Ontario in June 2016. These cultivars are considered to be moderately resistant to Fusarium head blight. More than 90 endophytic fungal isolates with 54 distinct morphotypes were obtained from these tissues. These fungal isolates were screened using dual culture plates for antagonism against three wheat pathogens: Fusarium graminearum, Waitea circinata, and Microdochium majus. Out of 54 isolates, 33 were found to cause obvious inhibition of pathogen growth or demarcation lines with at least one of the three wheat pathogens. These antagonistic strains were then tested for pathogenicity on wheat leaves in growth room tests, and 16 showed no phytopathogenicity. Among these non-pathogenic strains, three were selected and identified by internal transcribed spacer-polymerase chain reaction (ITS-PCR) as Valsa friesii, Simplicillium lamellicola and Cladorrhinum flexuosum. These three were then tested for their ability to inhibit disease in growth room tests. Hyphal plugs of these fungi inhibited the pathogenicity of wheat pathogens F. graminearum, and W. circinata on leaves of wheat seedlings, and reduced lesion lengths by 36–87% and 31%-86%, respectively. The wheat endophytes, S. lamellicola and C. flexuosum, are promising biocontrol agents against F. graminearum and W. circinata.