Transcriptome Analysis Reveals Multiple Hormones Signaling Pathways Mediate Adventitious Root Development in Watermelon Grafting

In this study, small-fruited watermelon 'HXX' was used as scion and pumpkin 'Anvil 3' as rootstock, and watermelon double-broken grafted seedlings were subjected to removal of cotyledons and true leaves (WP-3), decotyledonization (WP-1), decotyledonization (WP-2), and retention of true leaves with cotyledons (WP) treatments. The materials were subjected to various physiological indexes, transcriptome assay and WGCNA analysis to excavate the key target genes that regulate adventitious root generation. This study provided potential signaling pathways for the study of adventitious root formation of pumpkin as rootstock and identified candidate genes for the further study of how watermelon as scion influences the growth and development of adventitious roots of pumpkin rootstock, which is important for the improvement of survival rate of watermelon double-broken-root grafted seedlings and the acceleration of watermelon seedling emergence time.