Geographic distribution of Fusarium culmorum chemotypes associated with wheat crown rot in Iraq

Fusarium crown rot (FCR) is an important disease of wheat and other grains that has had a significant impact on cereal crop production worldwide. Fusarium species associated with FCR can also produce powerful trichothecenes mycotoxins that pose a considerable health risk to humans and animals that consume infected grains. In this study we examined Fusarium species of wheat from different regions of Iraq that showed FCR symptoms. Twenty-nine isolates were collected overall, and the marker gene translation elongation factor 1 alha (TEF-1α) was sequenced in order to determine their taxonomic identities. All isolates were determined to be F. culmorum, and primers targeting tri-cluster genes were used in order to further characterize isolates into specific trichothecene chemotype strains. Five of the 29 isolates were determined to be the nivalenol (NIV) chemotype, while the rest of the isolates recovered were the deoxynivalenol (DON) chemotype. All DON-type isolates produced 3Ac-DON, while the 15Ac-DON-type was not detected. The majority of the NIV-type isolates originated from wheat growing regions in the mid-latitudes of Iraq, while the DON-type isolates were recovered from areas distributed broadly across the country. To the best of our knowledge, this study is the first to report on the distribution of specific F. culmorum chemotypes from FCR diseased wheat in Iraq.