Methylome profiling in response to stress: mycotoxin (sporidesmin) exposure in sheep

Epigenetic modifications, including DNA methylation, alter gene expression without changing the DNA sequence, allowing for immediate and reversible modulation of physiological responses to abiotic/biotic stress. Facial eczema (FE) is a metabolic disease, which causes liver damage in affected animals. It occurs as a result of ingestion of the mycotoxin sporidesmin, which is found in the spores of the pasture-dwelling fungus Pseudopithomyces chartarum. This pilot study investigated DNA methylation changes that occurred as a result of sporidesmin exposure and identified a number of differentially methylation genomic regions in animals with liver stress. Of note, the HBA gene showed differential methylation in the promoter region; the HBA co-subunit of haemoglobin HBB has previously been identified as a QTL for the disease in sheep. There may be potential for DNA methylation markers to be used as a diagnosis proxy for FE or as a selection marker for resilient animals in the future.