Transcriptome and metabolome analysis of green- and russet skin pear cultivars identify key regulators of skin russeting

Different development of periderm make the full and partial russet of pear fruit skin, which negatively influence pear fruit appearance quality. The switch gene for russet development and the functional conservation of the homologs among diffeerent species showed to have multiple important implications to reveal the regulatory mechanisms underlying russet skin formation. In this study, two pear cultivars coupled with their mutants were used to explore the original signal and the underlying regulatory mechanisms of russet skin formation. RNA-sequencing and metabolomics were used to identify the key pathways and switch genes involved in the formation of russet pear skin, and identified genes involved in lignin biosynthesis, suberin biosynthesis, and suberin transporters. Four MYB transcription factors MYB6, MYB4, MYB39, and MYB308 have a high correlation with russet formation genes. qRT-PCR was performed to validate the transcriptome data. Two varieties and their mutants were used for the first time to explore the switch genes and underlying mechanisms of russet formation. We concentrated on the russet skin development in fruit, with an emphasis on exploring the original signal and the underlying regulatory mechanisms.