A comprehensive transcriptome analysis reveals the key mechanism related to leaf colour variation in a xantha mutant of Cucumis melo L.

This study aimed to investigate the key mechanisms underlying variation in leaf colour in the xantha mutant of Cucumis melo. The normal green C. melo inbred line ‘Baishami NO.1’ (wild type) and its spontaneous mutant’ 9388–1’ (xantha mutant) were collected. A comprehensive transcriptome analysis was conducted to identify differentially expressed genes (DEGs) between wild-type and xantha mutant C. melo in both the cotyledon and euphylla stages. A functional enrichment analysis, transcription factor (TF) prediction and a protein-protein interaction (PPI) network analysis for differentially expressed genes (DEGs) were subsequently conducted. In total, 234 up- and 551 down-regulated common DEGs in both the cotyledon and euphylla stages of xantha mutant C. melo were identified. These DEGs were significantly enriched in functions or pathways associated with photosynthesis and chloroplast development. Moreover, 18 common DEGs were identified as TFs that belonged to the ERF family. Notably, the photosynthesis-related gene MELO3C010813 (ZAT10) that was identified was also found to be a TF that belongs to the ethylene response factor family. A PPI network analysis showed that MELO3C023986 had the highest with TOP2 in Arabidopsis thaliana, and our findings revealed that expression of the xantha mutant phenotype may be associated with the abnormal expression of ZAT10, MAPK3, CRD1, PORA and ERF TFs, as well as the dysregulation of photosynthesis and chloroplast development.