Aminotransferase; part of the gene cluster that mediates the biosynthesis of the host-selective toxins (HSTs) AAL-toxins, sphinganine-analog mycotoxins responsible for Alternaria stem canker on tomato by the tomato pathotype. The biosynthesis starts with the polyketide synthase ALT1-catalyzed C-16 carbon chain assembly from one starter acetyl-CoA unit with malonyl-CoA extender units. ALT1 also selectively transfers methyl groups at the first and the third cycle of chain elongation for AAL toxin. The C-16 polyketide chain is released from the enzyme by a nucleophilic attack of a carbanion, which is derived from R-carbon of glycin by decarboxylation, on the carbonyl carbon of polyketide acyl chain (Probable). This step is probably catalyzed by a pyridoxal 5'-phosphate-dependent aminoacyl transferase ALT4 (Probable). The respective functions of the other enzymes encoded by the cluster have still to be elucidated (Probable). The sphingosine N-acyltransferase-like protein ALT7 seems not to act as a resistance/self-tolerance factor against the toxin in the toxin biosynthetic gene cluster, contrary to what is expected