Citrus phenylpropanoids and defence against pathogens. Part II: Gene expression and metabolite accumulation in the response of fruits to Penicillium digitatum infection

• Published in: Food chemistry 2013-01, Vol.136 (1), p.285-291
• Main Authors: Ballester, Ana-Rosa, Teresa Lafuente, M., González-Candelas, Luis
• Format: Article
• Language: English
• Subjects: Albedo; Biological and medical sciences; Chromatography, High Pressure Liquid; Citrus - chemistry; Citrus - genetics; Citrus - immunology; Citrus - metabolism; Citrus fruit; Citrus sinensis; Defence; Flavedo; Food industries; Fruit - chemistry; Fruit - genetics; Fruit - immunology; Fruit - metabolism; Fruit and vegetable industries; Fruits; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes; Infection; Metabolic profiling; Metabolites; Oranges; Pathogens; Pathways; Penicillium - physiology; Penicillium digitatum; Phenols - chemistry; Phenols - immunology; Phenols - metabolism; Phenylpropanoids; Plant Diseases - genetics; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Proteins - genetics; Plant Proteins - immunology; Plant Proteins - metabolism; Polymethoxylated flavones; Scoparone
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2012.08.006

► Expression of phenylpropanoid genes increased in response to pathogen infection. ► Changes in the metabolic profile of flavedo and albedo after Penicillium digitatum infection. ► Flavonoids are induced in citrus fruit in response to pathogen infection. The effect of infection of Citrus sinensis (var. Navelina) fruits with Penicillium digitatum was studied at gene expression and metabolite levels. In this study, expression of genes involved in the phenylpropanoid pathway was studied in the flavedo (outer coloured part of the peel) and albedo (inner white part) in response to pathogen infection. Results of the time-course experiment showed that maximal expression of 10 out of 17 phenylpropanoid genes analysed occurred at 48h post-inoculation, when decay symptoms started to appear, and mRNA levels either kept constant or decreased after 72h post-inoculation. To further investigate the putative involvement of the phenylpropanoid pathway in the defence of citrus fruit, changes in the metabolic profile of both tissues infected with P. digitatum was studied by means of HPLC-PDA-FD. Metabolite accumulation levels along the time course suggest that flavanones, flavones, polymethoxylated flavones and scoparone are induced in citrus fruit in response to P. digitatum infection, although with different trends depending on the tissue.