Despite the significance of external environmental factors in differentiation, putative factors
involved in differentiation of have not yet been fully understood. A
sporulation-specific proteome analysis of in the present study revealed that the
expression levels of more than 2,400 proteins were affected under conditions inducing
sporulation (0.6 M KCl) compared with normal conditions. Among the proteins with predicted
functions, two targets, AN1342 and AN9419, were functionally analyzed using targeted deletion
strains and phenotypic observations. For AN1342, because the deletion of the corresponding
open reading frame caused a reduction in stalk length during asexual development and in
pigment production in liquid culture, the gene was designated as sspA (short stalk & pigment).
Deletion of the AN9419 gene, which is predicted to encode alanyl-tRNA synthetase, led to
severe growth defects due to alanine auxotrophy and abolishment of asexual reproduction and
thus, the gene was designated as .