The effects of infection with Colletotrichum nymphaeae were studied on two strawberry cultivars: ‘Elsanta’ and ‘Honeoye’. Four treatments were established: (1) artificial inoculation; (2) spray application of pyraclostrobin + boscalid (Signum); (3) foliar spraying with calcium (Stopit); and (4) control (spraying with water). Sugars and organic acids as well as phenolic compounds were determined in strawberry fruit with the use of HPLC-MS. Infected fruit accumulated large amounts of total sugars and low levels of organic acids. The contents of ellagic acid derivatives, flavonols, oligomeric procyanidins, flavan-3-ols, and total phenolics were highest in inoculated strawberry fruit. Results indicated that fungicide and calcium sprayings did not alter polyphenolic levels in plant tissue.
Qualitative and quantitative changes of individual and total phenolics induced by Colletotrichum coccodesfungal infection have been studied in two susceptible sweet pepper cultivars ‘Soroksari’ and ‘Bagoly’, and the role of soluble phenolic compounds in plant's defence mechanism has been evaluated. Three distinct parts were analysed on pepper fruit: healthy tissue, anthracnose lesion, and bordering tissue, and individual phenolic compounds have been identified with the use of HPLC-MS system. In pepper fruit pericarp 21 phenolic compounds have been determined; the prevalent apigenin, quercetin and luteolin glycosides, chlorogenic acid and one chrysoeriol glucoside. C. coccodes infection increased the accumulation of chlorogenic acid, chrysoeriol glucoside, quercetin and luteolin glycosides in infected bordering tissue of both analysed pepper cultivars compared to healthy pepper tissue or symptomatic spot. Total apigenin derivatives did not show a significant increase in bordering tissue. This suggests a lesser role of apigenin glycosides in pepper plant defence against the Colletotrichum fungus.
The chemical composition of dwarf French bean was compared among five production systems: conventional, integrated, organic, and biodynamic production systems and the control. Determination of sugars and organic acids was performed with a HPLC system, and identification of individual phenolic compounds using HPLC-MS. The chemical composition of the beans was unaffected by the production systems; however, the content levels of individual compounds were changed.