A Bacillus subtilis gene for malate dehydrogenase (citH) was found dow
nstream of genes for citrate synthase and isocitrate dehydrogenase. Di
sruption of citH caused partial auxotrophy for aspartate and a require
ment for aspartate during sporulation. In the absence of aspartate, ci
tH mutant cells were blocked at a late stage of spore formation.