IDENTIFICATION OF MULTIPLE PEPC ISOGENES IN LEAVES OF THE FACULTATIVECRASSULACEAN ACID METABOLISM (CAM) PLANT KALANCHOE-BLOSSFELDIANA-POELLN CV TOM-THUMB

In the facultative Crassulacean Acid Metabolism (CAM) plant Kalanchoe blossfeldiana cv, Tom Thumb, CAM can be induced by short-day treatment or water deficiency stress, From young leaves of well-watered and wat er-stressed individuals of this plant, cDNA clones coding for a partia l sequence of the key enzyme of CAM, phosphoenolpyruvate carboxylase, were isolated after transcription of mRNA. cDNA polymorphism was estab lished by enzyme restriction profiles and sequencing data. Four PEPC i sogenes could be shown to exist in K. blossfeldiana forming two gene p airs, with 95%-98% homology inside and only 75% between the pairs. One cDNA sequence pair having a length of 1113 bp and an open reading fra me of 371 AA was identified as PEPC isoform specific for the C-3 state , whereas the pair having a length of 1116 bp and an open reading fram e of 372 AA could be attributed to the CAM state, These results were c onfirmed by Southern Blot hybridization. (EMBL, accession numbers X 87 818, X 87819, X 87820, X 87821.)