Fishy smell found in wheat field infected with karnal bunt is because of

The fishy smell found in wheat fields infected with karnal bunt is because of Trimethylamine.
Karnal bunt attacks durum wheat, rye, and triticale, a hybrid of wheat and rye. The smut fungus Tilletia indica, a basidiomycete, invades the kernels and obtains nutrients from the endosperm, leaving behind waste products with a disagreeable odor.
The disease produces dark color and a fishy smell on infected kernels. The odour is caused by the production of trimethylamine by the fungus.