PLDa1 is a phospholipid hydrolyzing enzyme playing multiple regulatory roles in stress response in plants. Its signaling activity is mediated via the PLDa1 dependent phosphatidic acid production, by its capacity to bind and modulate the G-protein complex or by interaction with other proteins. Relative quantitative proteomic analysis of two tDNA insertion Arabidopsis plda1 mutants has been performed. Remarkably, PLDa1 deficiency caused differential regulation of many proteins which form protein complexes.