Salt and drought limit the range of applications of perennial ryegrass(Lolium perenne L.), which is one of the important turf and forage grasses. Previous studies have suggested that pyrroline-5-carboxylate reductase(P5CR) might play a central role in proline accumulation in plants that are responsive to stresses. In the present study, the Lolium perenne L. pyrroline-5-carboxylate reductase(LpP 5CR) gene was cloned from leaves of the cultivar ‘Derby’ using the RACE technique. The full-length LpP 5CR gene was 1 047 bp in length, which comprised an open reading frame(ORF) of 840 bp in size. Sequence alignment revealed that the putative Lp P5 CR had a 94.3% similarity to Ta P5 CR. q RT-PCR displayed that the mR NA levels of the LpP 5CR gene were almost the same as that in the roots, stems, and leaves of perennial ryegrass seedlings subjected to normal condition or NaC l treatment for 1 h. Moreover, the transcription level of LpP 5CR was up- or down- regulated with Na Cl, polyethylene glycol(PEG), cold, or abscisic acid(ABA) treatment for 3 to 48 h. In addition, confocal microscopy localized the GFP-Lp P5 CR fusion protein to the cytoplasm of onion epidermal cells. These findings suggest that LpP 5CR encodes a cytoplasmic P5 CR protein that plays an important role in the response of perennial ryegrass to various stresses. Salt and drought limit the range of applications of perennial ryegrass (Lolium perenne L.), which is one of the important turf and forage grasses. Previous studies have suggested that pyrroline-5-carboxylate reductase (P5CR) might play a central role in proline accumulation in plants that are responsive to stresses. In the present study, the Lolium perenne L. pyrroline-5-carboxylate reductase (LpP 5CR) gene was cloned from leaves of the cultivar ’Derby’ using the RACE technique. The full- length LpP 5CR gene was 1 047 bp in length, which comprised an open reading frame (ORF) of 840 bp in size. Sequence alignment revealed that the putative Lp P5 CR had a 94.3% similarity to Ta P5 CR. Q RT-PCR displayed that the mR NA levels of the LpP 5CR gene were almost the same as that in the roots, stems, and leaves of perennial ryegrass seedlings subjected to normal condition or NaCl treatment for 1 h. Moreover, the transcription level of LpP 5CR was up- or down-regulated with Na Cl, polyethylene gl The addition of confocal microscopy localized the GFP-Lp P5 CR fusion protein to the cytoplasm of onion epidermal cells. These findings suggest that LpP 5CR encodes a cytoplasmic P5 CR protein that plays an important role in the response of perennial ryegrass to various stresses.