Comparative metabolome and transcriptome analysis of anthocyanin biosynthesis in fig (Ficus carica L.)

Fig (Ficus carica L.), which has vital health-benefiting properties such as anthocyanins, is of paramount importance in the Mediterranean diet. Turkiye is the world's leading producer of figs and recognizes this fruit as a key part of its cuisine. However, despite their diversity and rich medicinal value, local figs are overlooked and poorly examined for the biochemical fingerprints associated with their nutritional quality, and little information is available on their molecular structure beyond fig anthocyanin biosynthesis and coloration. This study was therefore first designed to analyze the peels and pulps of eight Turkish figs for their total phenolic composition, sugars, and antioxidant capacity. Thirty-one phenolic compounds were detected using High-Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-MS/MS) method. Among the peels and pulps, the highest mean value of colored and colorless phenolic compounds was found in the '01-1N-58' (dark violet-purple) genotype. Furthermore, differentially expressed genes involved in the fig anthocyanin mechanism were assessed. For this, RNA-Seq analysis was performed on the peels of the dark-purple '01-1N-58' genotype and greenish-yellowish 'Sarilop' cultivar using Illumina NovaSeq 6000™. Based on these genes, gene ontology (GO) analysis was performed. A total of 21102 differentially expressed genes were observed, and 3542 up-regulated and 3164 down-regulated genes in the libraries of two fig samples were identified. Additionally, qRT-PCR analyses were also conducted to validate the results of the expression of genes in RNA-Seq. In conclusion; our study showed that the diversity of bioactive compounds in the peels of eight fig cultivars and genotypes is high. It has been demonstrated once again that dark-colored fruits are important for health, and it has been emphasized that the evaluation of fig genetic resources in this context may be important for more effective use.As a result of transcriptome analyzes, important information has been obtained for the determination of anthocyanin-related genes, and it is thought that these data will shed light on future studies for the identification and functional analysis of genes effective in anthocyanin metabolism.