PR001865 (Project)

Description:Holm oak (Quercus ilex) is considered one of the major structural elements of the Mediterranean forests and the agrosilvopastoral Spanish “dehesa”, representing an outstanding example of ecological and socio-economic sustainability of forest ecosystems. The exotic pathogen Phytophthora cinnamomi is one of the most aggressive of woody species, and together drought is considered one of the main drivers of holm oak decline. The effect and responses of P. cinnamomi inoculation has been studied on the offspring of mother trees growing in declined and non-declined areas of two Andalusian populations (Cordoba and Huelva). Damage symptoms, mortality, and chlorophyll fluorescence have been evaluated in seedlings inoculated under humid and drought conditions. The effect and responses depended on the population, being more accused in Huelva than in Cordoba population. An integrative proteomic and metabolomic analysis revealed the involvement of different metabolic pathways in response to the pathogen in both populations, such as amino acid metabolism pathways in Huelva, and terpenoids and flavonoids biosynthesis in Cordoba. However, a differential response was not observed between seedlings inoculated under humid and drought conditions. A protective mechanism of the photosynthetic apparatus is launched in response to defective photosynthetic activity in inoculated plants, which seems to be more efficient in the Cordoba population. In addition, enzymes and metabolites of the phenylpropanoid and flavonoid biosynthesis pathways may confer higher resistance to Cordoba population. Some of these enzymes are proposed as markers of resilience, among which glyoxalase I, glutathione reductase, thioredoxin reductase, and cinnamyl alcohol dehydrogenase are candidates.