Converts proline to delta-1-pyrroline-5-carboxylate (By similarity). Through proline catabolism, promotes reactive oxygen species (ROS) production and the transcription of skn-1 target genes in response to bacterial infection by P.aeruginosa (PubMed:27974198). a quinone + L-proline = (S)-1-pyrroline-5-carboxylate + a quinol + H(+) Amino-acid degradation; L-proline degradation into L-glutamate; L-glutamate from L-proline: step 1/2. Up-regulated by infection with P.aeruginosa. RNAi-mediated knockdown reduces the survival incidence, results in increased bacterial load and reduces ROS production following infection by P.aeruginosa (PubMed:27974198). RNAi-mediated knockdown inhibits the nuclear accumulation of the transcription factor skn-1 and reduces the expression of skn-1 transcriptional targets including gst-4 following infection by P.aeruginosa (PubMed:27974198). RNAi-mediated knockdown suppresses the pro-survival effects of the addition of exogenous proline following infection by P.aeruginosa (PubMed:27974198). Belongs to the proline oxidase family.