Threonine aldolase involved in threonine degradation to glycine. May play a role in the removal of L-allo-threonine. L-threonine = acetaldehyde + glycine L-allo-threonine = acetaldehyde + glycine Amino-acid degradation; L-threonine degradation via aldolase pathway; acetaldehyde and glycine from L-threonine: step 1/1. Expressed in root tips, seedlings, carpels and seeds. No visible phenotype under normal growth conditions, but mutant plants have 50-fold increase in seed Thr content and 2-fold decrease in seedling Gly content. Belongs to the threonine aldolase family.