Promoter of Vegetable Pea PsPIP2-4 Responds to Abiotic Stresses in Transgenic Tobacco

Plasma membrane intrinsic proteins (PIPs), one sub-family of aquaporins (AQPs), are responsible for plant abiotic stress responses. However, little information is currently available about the stress responsiveness of the <i>PIP</i> promoter in vegetable pea. In the present study, one novel promoter of <i>PsPIP2-4</i> which shared high similarity to the <i>PIP2</i>-type <i>AQPs</i> from other plants, was isolated. Quantitative real-time PCR (qRT-PCR) assays suggested that <i>PsPIP2-4</i> was predominantly expressed in leaves and abundantly induced by abiotic stress treatments (polyethylene glycol (PEG) 6000, NaCl, and methyl jasmonate (MeJA)). Further, the promoter activity of <i>PsPIP2-4</i> was verified in transgenic tobacco plants. Beta-glucuronidase (GUS) staining driven by the <i>PsPIP2-4</i> promoter confirmed that it was mainly detected in the leaves of transgenic seedlings, especially in the guard cells. Exposure of transgenic seedlings to various environmental stimuli proved that the promoter activity of <i>PsPIP2-4</i> was abundantly strengthened by osmotic, salt, and MeJA stresses. This research provides one stress-inducible promoter enabling targeted gene expression under abiotic stresses and demonstrates its usefulness in the genetic improvement of plant stress resistance.