Clostridium perfringens is a Gram-positive rod that is widely distributed in nature and is the etiological
agent of several human and animal diseases. The complete genome sequence of C. perfringens strain 13
has been determined and multiple two-component signal transduction systems identified. One of these
systems, designated here as the MalNO system, was analyzed in this study. Microarray analysis was used
to carry out functional analysis of a malO mutant. The results, which were confirmed by quantitative
reverse-transcriptase PCR, indicated that genes putatively involved in the uptake and metabolism of
maltose were up-regulated in the malO mutant. These effects were reversed by complementation with
the wild-type malO gene. Growth of these isogenic strains in medium with and without maltose showed
that the malO mutant recovered more quickly from maltose deprivation when compared to the wild-type
and complemented strains, leading to the conclusion that the MalNO system regulates maltose utilization
in C. perfringens. It is postulated that this regulatory network may allow this soil bacterium and
opportunistic pathogen to respond to environmental conditions where there are higher concentrations
of maltose or maltodextrins, such as in the presence of decaying plant material in rich soil.