Identification of Fusarium species associated with Fusarium head blight of wheat in the North of Iran and phylogenetic analysis of the dominant species

In order to determine the causal agents of Fusarium head blight, during 2015–16, wheat heads with disease symptom were collected from 10 and six main wheat production areas of Golestan and Mazandaran provinces (N Iran), respectively. A total of 431 Fusarium isolates were obtained belonging to nine Fusarium species based on their morphological characteristics. Fusarium graminearum species complex had the highest frequency among the species in both provinces, Golestan (52.0%) and Mazandaran (55.8%). Fusarium culmorum, F. equiseti, F. Acuminatum, and F. compactum had the highest mean of frequency in both provinces with 13.5, 9.7, 6.0 and 3.7%, respectively after F. graminearum. Also, F. cerealis, F. Avenaceum, and F. proliferatum and some unidentified isolates a total of 14% of the isolates were calculated. The lowest frequency was related to F. subglutinans (1%) that was isolated only from Golestan province. In order to determine the phylogeny of F. graminearum species complex in the North Iran, 53 out of 229 isolates were selected based on their distribution in the sampled areas. Partial genes of translation elongation factor 1-alpha (TEF) and putative reductase (RED) were amplified using specific primers. A commercial sequencing facility was used to generate fungal sequences. Almost all strains of F. graminearum species complex belonged to F. graminearum sensu stricto. The results indicated a homogeniety within F. graminearum species complex, however, there was a minor morphologically differences between some strains.