Cardiolipin (CL) is a unique phospholipid which localizes to the mitochondrial inner membrane. In recent years, the biochemical feature of CL has been elucidated. CL is essential to mitochondrial energy production, mitochondrial membrane dynamics, and regulation of mitochondrial apoptotic pathway. However, its physiological functions are still unclear in vivo. In CL de novo biosynthetic pathway, CL is synthesized through phosphatidylglycerophosphate (PGP) synthase and CL synthase. We identified
pgs-1 and
crls-1 genes in C.elegans genome sequences as putative homologue of PGP synthase and CL synthase, respectively.To investigate about the physiological functions of CL, we examined the phenotype of
crls-1 gene deletion mutant. The mutant,
crls-1(
tm2542), showed viable but sterile phenotype in hermaphrodites. The length and diameter of distal gonad of
crls-1(
tm2542) were shorter than those of wild type. Moreover, we also confirmed that
crls-1(
tm2542) had lower content of CL by comparing the proportion of phospholipid contents between
crls-1(
tm2542) and wild type.We investigated the function of mitochondria in gonad with the measurement of mitochondrial membrane potential, using fluorescent probe, DiSC3. We found that its potential in gonad significantly decreased in
crls-1(
tm2542). Furthermore, we evaluated the rhythmic behavioral defects of
crls-1(
tm2542) as a parameter of mitochondrial function.
crls-1(
tm2542) showed slow pharyngeal pumping, and prolonged defecation cycle. This behavioral defect is similar to
nuo-1 (complex I) and
atp-2 (complex V) mutants which have defective function in mitochondria.These results suggest that CL has an important role for mitochondria also in C.elegans. Growth, proliferation and exercise require cellular energy, and mitochondria generate cellular energy product, ATP. Therefore, CL can play a role in cellular respiration to generate ATP in vivo.