Integrated Transcriptomic and Metabolomic Insights into the Molecular Mechanisms of Akizuki Pear Corky Disease

Corky disease significantly affects the yield and quality of Akizuki pear, but the molecular mechanism underlying its formation has not yet been elucidated. Here, we characterized differences in the cell components and biochemical parameters of Akizuki pear corky fruit and healthy fruit and performed transcriptomic and metabolomic analyses. The content of cellulose and hemicellulose was significantly higher and the content of pectin was significantly lower in diseased fruit than in healthy fruit. A total of 1,183 differentially expressed genes (DEGs) were identified, including 634 up-regulated genes and 549 down-regulated genes. These DEGs were mainly enriched in cell wall remodeling, redox reactions, and transferase activity. DEGs were also involved in phenylpropane metabolism, plant hormone signal transduction, and starch and sucrose metabolism. The expression of genes related to lignin (PpyPAL, Ppy4CL, PpyCCR), cellulose (PpyCesA, PpyXET), and pectin degradation (PpyPME2, PpyGAUT, PpyUGase) was significantly up-regulated. A total of 439 significant differentially accumulated metabolites were identified, and significant changes in metabolites associated with carbohydrate, amino acid, and lipid metabolism pathways were observed during the formation of corky disease. Overall, our findings shed new light on the pathogenesis of Akizuki pear corky disease and will aid its prevention and treatment.