Extensive transcriptome changes underlying the fruit skin colour intensity variation in purple eggplant

Fruit skin colour intensity is one of the most important economic traits of purple eggplant. A wide diversity for fruit skin colour intensity exists in purple eggplant and the accumulation of anthocyanins and chlorophylls of fruit skin mainly affected colour intensity. However, limited information is available contributing to the molecular mechanisms underlying fruit skin colour intensity variation in purple eggplant. In the present study, variation of two purple eggplant advanced lines EP26 and EP28, with different fruit skin colour intensity was investigated. Higher anthocyanin contents and lower chlorophyll contents were observed in EP26 with deeper fruit skin colour intensity at two developmental stages. Comparative transcriptome analysis of EP26 and EP28 identified a total of 2218 differential expressed genes (DEGs) at two developmental stages. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that these DEGs were mainly involved in flavonoid biosynthesis and photosynthesis. In addition, a total of 131 transcription factors including MYB, bHLH, WRKY, and NAC exhibited dynamic changes, which might be responsible for the variation of fruit pigments accumulation between EP26 and EP28. Taken together, these results expand our knowledge of molecular mechanisms underlying fruit skin colour intensity variation in eggplant, which allowing for improvement of fruit coloration in eggplant breeding.

Automated summary

Variation in fruit skin color intensity of purple eggplant involves accumulation of anthocyanins and chlorophylls, and comparative transcriptome analysis revealed differential gene expression between two purple eggplant lines with different color intensity. Dynamic changes in transcription factors may be responsible for the variation in fruit pigment accumulation between the two lines.