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Holm oak (Quercus ilex) is considered to be one of the major structural elements of Mediterranean forests and the agrosilvopastoral Spanish "dehesa", making it an outstanding example of ecological and socioeconomic sustainability in forest ecosystems. The exotic Phytophthora cinnamomi is one of the most aggressive pathogens of woody species and, together with drought, is considered to be one of the main drivers of holm oak decline. The effect of and response to P. cinnamomi inoculation were studied in the offspring of mother trees from two Andalusian populations, Cordoba and Huelva. At the two locations, acorns collected from both symptomatic (damaged) and asymptomatic (apparently healthy) trees were sampled. Damage symptoms, mortality, and chlorophyll fluorescence were evaluated in seedlings inoculated under humid and drought conditions. The effect and response depended on the population and were more apparent in Huelva than in Cordoba. An integrated proteomic and metabolomic analysis revealed the involvement of different metabolic pathways in response to the pathogen in both populations, including amino acid metabolism pathways in Huelva, and terpenoid and flavonoid biosynthesis in Cordoba. However, no differential response was observed between seedlings inoculated under humid and drought conditions. A protective mechanism of the photosynthetic apparatus was activated in response to defective photosynthetic activity in inoculated plants, which seemed to be more efficient in the Cordoba population. In addition, enzymes and metabolites of the phenylpropanoid and flavonoid biosynthesis pathways may have conferred higher resistance in the Cordoba population. Some enzymes are proposed as markers of resilience, among which glyoxalase I, glutathione reductase, thioredoxin reductase, and cinnamyl alcohol dehydrogenase are candidates. [ABSTRACT FROM AUTHOR]

Humans have used Quercus ilex acorns as a staple food since ancient times. Recently, their nutritional and nutraceutical value has revived interest for human consumption. Ensuring their safety as food requires assessing their allergenic potential. In this work, we predicted the allergenic profile of acorns by in silico analysis of the Q. ilex genome and transcriptome. In addition, immunoblot analysis of pooled sera from patients allergic to various dry fruits was performed, with immunoreactive bands subjected to mass spectrometry analysis. The most remarkable allergens identified belong to the Bet v 1, profilin, prolamin, Hsp70 and cyclophilin families. Acorns from different mother trees exhibited also different IgE sensitization patterns. Thus, acorns from trees showing damage symptoms, and located in declined areas, had higher allergen contents than those from healthy ones, which corresponded to higher abundance of stress-related proteins. • Allergens in Holm oak seeds were identified using a combination of bioinformatic, proteomic, and immunochemical approaches. • The most remarkable allergens identified belong to the Bet v 1, profilin, prolamin, Hsp70 and cyclophilin families. • Allergen composition was similar between the four types of acorns but revealed quantitative differences. • Acorns from damaged trees were found to contain a higher amount of allergenic stress-related proteins. [ABSTRACT FROM AUTHOR]