Comparative transcriptomic and proteomic analyses of the green and white parts of chimeric leaves in Ananas comosus var. bracteatus

BACKGROUND: Ananas comosus var. bracteatus has high ornamental value due to its chimeric leaves. However, the chimeric trait is very unstable in red pineapple plants, and transcriptional variation between the two types of cells (white/green cells) and the molecular mechanism responsible for their albino phenotype remain poorly understood. METHODS: Comparative transcriptomic and proteomic analyses of the white parts (Whs) and green parts (Grs) of chimeric leaves were performed. RESULTS: In total, 1,685 differentially expressed genes (DEGs) (712 upregulated and 973 downregulated) and 1,813 differentially abundant proteins (DAPs) (1,018 with low abundance and 795 with high abundance) were identified. Based on Gene Ontology (Go) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, the DEGs were mostly involved in carbon fixation in photosynthetic organisms, porphyrin and chlorophyll metabolism and oxidative phosphorylation, while proteomic analysis revealed that DAPs were mostly related to ribosomes, photosynthesis, photosynthesis antennas, and porphyrin and chlorophyll metabolism. Combined analysis showed increased mRNA levels but low abundance of nine proteins level in Whs /Grs related to photosynthetic pigment and photosynthesis. Transcriptional changes, posttranscriptional regulation and translational alterations of key enzymes involved in chlorophyll biosynthesis and photosynthesis may play important roles in the albino parts of chimeric leaves.