Metabolite profiling of four different tissue locations in grape leaf of brown spot disease caused by Pseudocercospora vitis

摘要

Infected ‘Campbell Early’ grape leaf tissues were collected according to four different tissue locations of brown spot disease: center of the lesion (A), lesion border (C) the uninfected leaf tissue (D) and tissue from A and C as well as the lesion halo (B). A total of 118 metabolites were identified using polar phase GC-MS analysis with sample derivatization and annotated four different sampling tissues. Metabolites were clustered into three groups according to tissues (tissue A, tissue B, and tissues C and D) in the PCA score plot. Tissues C and D were separated in the PCA plot; therefore, they had similar metabolite contents variations. 20 of the metabolites were significantly related to tissues A and C in the S-plot of OPLS-DA. Most of the metabolites, including caffeic acid, succinic acid, and citric acid, were increased in related contents in uninfected tissues (C and D) compared with lesions (A and B). In contrast, D-mannitol, xylitol, and raffinose were increased in the lesion tissues (A and B). Neohesperidin, lactulose, and dehydroascorbic acid were found in the tissue B. As a result, those three metabolites can be expected to relate to the defense mechanism of grapes against brown leaf spot disease.