9:00 am - 10:00 am
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES PhD Final Exam Seminar by Maryamsadat Vaziriyeganeh. This seminar is open to the general public to attend.
PhD with Dr. Janusz Zwiazek and Dr. Micaela Carvajal
Thesis Topic: Role of Water Transport and Aquaporins in Salinity Tolerance of Northern Grasses
The significance of aquaporin-mediated water transport in salinity tolerance was examined in three northern grass species varying in salt tolerance. Sustained growth and enhanced cell hydraulic conductivity in the halophytic grass Puccinellia nuttalliana were associated with the presence of Na+ in the salt treatments. In this grass, NaCl treatment increased transcript levels of the HKT1;5 transporter and several PIP aquaporins, including PIP2;2, and decreased transcript levels of the TIP aquaporin implying their roles in water and ion homeostasis. In yeast protoplasts expressing PnuPIP2;2, the measurements of water fluxes and Na+ uptake demonstrated that NaCl enhanced water transport across this aquaporin and that PnuPIP2;2 also functions as a Na+ transporter. Structural analysis revealed high hydrophilicity of PnuPIP2;2 and its elaborate pore structure that likely contribute to the unique transporting properties of this aquaporin. The results point to the importance of aquaporins in maintaining water balance of salt tolerant grasses under salinity conditions.