Transcriptomic and sugar metabolic analysis reveals molecular mechanisms of peach gummosis in response to Neofusicoccum parvum infection

Peach gummosis, a devastating disease caused by <i>Neofusicoccum parvum</i>, significantly shortens peach tree lifespan and reduces the yield of peach trees. Despite its impact, the molecular mechanism underlying this disease remains largely unexplored. In this study, we used RNA-seq, sugar metabolism measurements, and an integrated transcriptional and metabolomic analysis to uncover the molecular events driving peach gummosis. Our results revealed that <i>N. parvum</i> infection drastically altered the transcripts of cell wall degradation-related genes, the log₂Fold change in the transcript level of <i>Prupe.1G088900</i> encoding xyloglucan endotransglycosylase decreased 2.6-fold, while <i>Prupe.6G075100</i> encoding expansin increased by 2.58-fold at 12 hpi under <i>N. parvum</i> stress. Additionally, sugar content analysis revealed an increase in maltose, sucrose, L-rhamnose, and inositol levels in the early stages of infection, while D-galactose, D-glucose, D-fructose consistently declined as gummosis progressed. Key genes related to cell wall degradation and starch degradation, as well as UDP-sugar biosynthesis, were significantly upregulated in response to <i>N. parvum</i>. These findings suggest that <i>N. parvum</i> manipulates cell wall degradation and UDP-sugar-related genes to invade peach shoot cells, ultimately triggering gum secretion. Furthermore, weighted gene co-expression network analysis (WGCNA) identified two transcription factors, <i>ERF027</i> and <i>bZIP9</i>, as central regulators in the downregulated and upregulated modules, respectively. Overall, this study enhances our understanding of the physiological and molecular responses of peach trees to <i>N. parvum</i> infection and provide valuable insights into the mechanisms of peach defense against biotic stresses.