One dry summer: a leaf proteome study on the response of oak to drought exposure.

One of the most prominent hallmarks of the expected climate change in Europe is the higher prevalence of longer and more intense periods of summer drought. To preserve European oak forests, of considerable importance for European economical and ecological development, under these conditions knowledge on the mechanisms by which broad-leaved trees cope with drought is needed. In this study the effect of one season of drought stress, corresponding in length and soil water content to a dry summer, on young pedunculate oak trees (Quercus robur L.) was investigated by monitoring phenotypical parameters, the analysis of carbohydrate accumulation and a 2D-DIGE-based proteome study of leaves. In our experimental system, mimicking the conditions of a dry summer, the plants displayed reduced growth, moreover the transition through the developmental stages was affected. The data obtained during this study, supported by a separately published gene expression analysis study, indicated that the oak tried to adapt its metabolism in order to maintain its full molecular functionality. Initially the plants seemed to be able to cope with the imposed stress. However prolonged drought exposure overwhelmed the adaptive mechanisms and at the last sampling point of this study the molecular machinery succumbed.