Abstract:
Boron is an essential micronutrient for plants and animals; however, it can be toxic when present at high
concentrations. Th e purpose of this study was to understand the mechanisms of boron tolerance in the Turkish barley
(Hordeum vulgare) Anadolu cultivar. For this purpose, 2-dimensional electrophoresis (2-DE) was used to screen
diff erentially expressed proteins for both control and boron-stressed Anadolu barley genotypes. Seven proteins were
revealed by 2-DE: 1) ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCo large chain), 2) TLP5, a thaumatin-like
protein, 3) PR5, a basic pathogenesis-related protein, 4) a RNase S-like protein, 5) a PSI type III chlorophyll a/b-binding
protein, 6) a light-harvesting complex I LHC I, and 7) the vacuolar proton-translocating ATPase subunit E protein.
Th ese were found to be upregulated in response to boron treatment. Even though the protein encoded by the V-ATPase
subunit E gene was overexpressed, its transcript level was downregulated by boron treatment. Heterologous expression
of the barley V-ATPase subunit E gene in yeast provided boron resistance to yeast cells. Th ese results indicated that the
V-ATPase subunit E gene was functional and conferred tolerance to toxic boron levels in yeast and might play a role in
the overall boron tolerance of barley.
