Changes in arabinogalactan proteins (AGPs) distribution in apple (Malus x domestica) fruit during senescence

In the present study, we analysed the distribution of AGPs in cells forming the epidermal, parenchymal, and sclerenchyma tissue and proposed possible roles of AGPs during apple fruit senescence. The use of immunofluorescence reactions with JIM13, JIM15, and MAC207 antibodies (CLSM) allowed for the determination of the presence and changes in the localization of AGP epitopes at different periods of apple fruit storage. The immunogold labelling technique (TEM) revealed the changeable location of AGPs in cell walls. The storage-dependent subcellular localization of AGPs spread from the periphery of the fresh fruit cell walls to the whole surface after 3 months of storage. The variable AGP arrangement in the fruit tissues was strictly related to fruit senescence; this allowed us to form a conclusion about their specific function in the loss of firm texture which is associated with fruit quality and storage limitations.