E1-like activating enzyme involved in the 2 ubiquitin-like systems required for cytoplasm to vacuole transport (Cvt) and autophagy (By similarity). Activates ATG12 for its conjugation with ATG5 and ATG8 for its conjugation with phosphatidylethanolamine (By similarity). Both systems are needed for the ATG8 association to Cvt vesicles and autophagosomes membranes (By similarity). Autophagy is essential for maintenance of amino acid levels and protein synthesis under nitrogen starvation (By similarity). Required for selective autophagic degradation of the nucleus (nucleophagy) as well as for mitophagy which contributes to regulate mitochondrial quantity and quality by eliminating the mitochondria to a basal level to fulfill cellular energy requirements and preventing excess ROS production (By similarity). Autophagy is required for proper vegetative growth, asexual/sexual reproduction, and full virulence (PubMed:28894236). Autophagy is particularly involved in the biosynthesis of deoxynivalenol (DON), an important virulence determinant (PubMed:28894236). Homodimer (By similarity). Interacts with ATG8 through a thioester bond between Cys-550 and the C-terminal 'Gly-116' of ATG8 and with ATG12 through a thioester bond between Cys-550 and the C-terminal 'Gly-160' of ATG12 (By similarity). Interacts also with ATG3 (By similarity). The C-terminal residues 650 to 689 are required for homodimerization, as well as the interactions with ATG3, ATG8 and ATG12; and the C-terminal 17 residues are required for the ATG8 lipidation (By similarity). The GxGxxG motif is important for the function, possibly through binding with ATP (By similarity). Significantly decreases the radial growth of colonies under nutrient-rich conditions (PubMed:28894236). Causes only mild infection in point-inoculated spikelets of flowering wheat heads and impairs the spreading to nearby spikelets (PubMed:28894236). Reduces strongly the production of deoxynivalenol (DON), an important virulence determinant (PubMed:28894236). Belongs to the ATG7 family.