Identification of key leaf color-associated genes in Gleditsia sinensis using bioinformatics

This study aimed to explore leaf-color associated genes in Gleditsia sinensis (G. sinensis) using bioinformatics methods. Green, purple, and yellow leaves were collected from G. sinensis in Shandong Institute of Pomology. Total RNA was collected from leaves and subjected to transcriptome sequencing. Differentially expressed genes (DEGs) were identified among the different colored leaves using RSEM method followed by functional enrichment analysis. Finally, qRT-PCR analysis was used to assess the expression of several pigment-related genes enriched in significant GO or KEGG terms. A total of 10,953, 14,961, and 8916 DEGs were identified between green vs. purple leaves, green vs. yellow leaves, and purple vs. yellow leaves, respectively. Among the green vs. purple leaves, DEGs were significantly enriched in terms of iron ion binding, tetrapyrrole binding, (e.g., CYP26A1, CYP97A3, and CYP86A1), and starch and sucrose metabolism (e.g., TPS and VTC2). DEGs for green/purple vs. yellow groups were markedly enriched in circadian rhythm-plant KEGG pathway, including ELF3 and CHS. Compared with their expression in green leaves, CYP26A1, CYP97A3, CYP86A1, TPS and VTC2 were significantly downregulated in purple leaves, while downregulation of ELF3 and upregulation of CHS was detected in yellow leaves. CYPs (e.g., CYP26A1 and CYP97A3) might play critical roles in the determination of leaf color in G. sinensis via iron ion and tetrapyrrole binding. In addition, genes related to starch and sucrose metabolism (e.g., TPS and VTC2), and circadian rhythms (e.g., ELF3 and CHS) might also be involved in controlling leaf color.