Cloning and expression analysis of pepper chlorophyll catabolite reductase gene CaRCCR

Opening the porphyrin macrocycle of pheophorbide a and forming the primary fluorescent chlorophyll catabolites are key steps in the chlorophyll catabolism pathway. These steps are catalyzed by pheophorbide a oxygenase and red chlorophyll catabolite reductase (RCCR). In this study, a novel RCCR gene, CaRCCR, was isolated from the pepper (Capsicum annuum L.). The full-length CaRCCR complementary DNA is comprised of 1173 bp, contains an open reading frame of 945 bp, and encodes a 314-amino acid protein. This deduced protein belongs to the ferredoxin-dependent bilin reductase family. Amino acid sequence alignment showed that CaRCCR shared a high homology to other higher plant RCCR proteins. CaRCCR expression, as determined by quantitative real-time polymerase chain reaction, was higher in the leaves than the roots, stems, flowers, and immature fruits. CaRCCR expression was almost constant during all phases of leaf development. It was upregulated by abscisic acid, methyl jasmonate, and salicylic acid. Moreover, CaRCCR was induced by high salinity and drought stress treatments; it was also slightly regulated by Phytophthora capsici. Taken together, these results suggest that CaRCCR is involved in defense responses to various stresses.