S. Gama-castro et al., Azotobacter vinelandii aldehyde dehydrogenase regulated by sigma(54): Rolein alcohol catabolism and encystment, J BACT, 183(21), 2001, pp. 6169-6174
Encystment in Azotobacter vinelandii is induced by n-butanol or beta -hydro
xybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase,
that was named aldA. An aldA mutation impaired bacterial growth on n-butan
ol, ethanol, or hexanol as the sole carbon source. Expression of aldA incre
ased in cells shifted from sucrose to n-butanol and was shown to be depende
nt on the alternative sigma (54) factor. A mutation in rpoN encoding the si
gma (54) factor also impaired growth on alcohols. Encystment on n-butanol,
but not on BHB, was impaired in aldA or rpoN mutants, indicating that n-but
anol is not an inducer of encystment by itself but must be catabolized in o
rder to induce encystment.