TaPP2AbB-γ, a wheat regulatory subunit of PP2A enhanced abiotic stress tolerance

Protein dephosphorylation mediated by serine/threonine protein phosphatase 2A (PP2A) plays critical roles in regulation of abiotic stress responses in plants. Here, we report the involvement of a B '' regulatory subunit of PP2A in wheat (Triticum aestivum L.), TaPP2AbB ''-gamma, in the positive regulation of stress responses. The transcript of TaPP2AbB ''-gamma was induced in roots of wheat seedlings by salinity, drought, cold stresses and exogenous ABA application. Overexpression of TaPP2AbB ''-gamma enhanced the tolerance to various environmental stresses in transgenic Arabidopsis seedlings. Yeast two-hybrid assay demonstrated that TaPP2AbB ''-gamma interact with the first 100 amino acids of TaBZR1, a positive regulator of Brassinosteroids (BRs) signaling. The expression of TaBZR1 gene was up-regulated in roots upon exposure to NaCl stress. All our results suggested that TaPP2AbB ''-gamma functions in improving abiotic stress tolerance by directly binding to TaBZR1, pointing to a possible cross-talk of BR signaling with TaPP2AbB ''-gamma mediated stress response.