The identified protein species were classified into six
categories according to their biological activity [35]. As leaves
were emphasised in this study, the major category found was
energy (58%). Metabolism was the second most common
category (19%), and the other identified categories were disease/
defence, protein destination and storage, and others (see Fig. 3). It
is important to note that almost 10% of the differentially
abundant proteins were found to be ribulose biphosphate
carboxylase (RuBisCo), which is responsible for the first step of
the Calvin cycle and, in fact, for the fixation of CO2 in its organic
form in plants [33].