Project description:Ananas comosus var. bracteatus has high ornamental value and widespread application because of its chimeric leaves. However, little is known about the molecular mechanism regulating this characteristic. Here, comparative transcriptomic and proteomic analyses of the white parts (Whs) and green parts (Grs) of the chimeric leaves were performed to identify differentially expressed genes (DEGs) and differentially expressed proteins (DEPs). In total, 1,685 DEGs, including 712 up- and 973 down-regulated ones, and 5,428 DEPs, including 1,018 up- and 795 down-regulated ones, were identified between the Whs and Grs. Comparisons with the GO and KEGG annotations revealed that the DEGs were involved mostly in carbon fixation, porphyrin and chlorophyll metabolism and oxidative phosphorylation. The DEPs were mainly involved in ribosomes, photosynthesis, photosynthesis antennas, and porphyrin and chlorophyll metabolism. Combined analysis showed that nine proteins related to chlorophyll biosynthesis, photosynthetic pigments, and photosynthesis were unchanged at mRNA level but suppressed at protein level. These results indicated that the albino phenotype of the Whs was caused by the proteomic-level suppression of key enzymes involved in the chlorophyll biosynthesis pathway and that translational and post-translational regulation may play important roles in both the biosynthesis of photosynthetic pigments and photosynthesis. Biological significance: Leaves of Ananas comosus var. bracteatus serve as the best materials for the study of albino mechanism. Because the chemic trait of A. comosus var. bracteatus is unstable and the molecular mechanism of the albino cells was poorly understood, we performed comparative analyses both at the transcriptome and proteome levels. This work revealed suppressed proteomic-level and translational and post-translational regulation contribute to the albino phenotype formation. Our results provide better information concerning the molecular mechanism within the chimeric leaves of A. comosus var. bracteatus.
