Abstract
Aquaporins are major membrane proteins, which facilitate membrane transport of water and other small molecules. Plasma membrane aquaporins (PIPs) play a key role of intercellular water transport. Several studies have shown that PIPs response to abiotic stresses and alter their expression or intracellular localization. We examined changes in mRNAs levels of PIPs under high temperature conditions.
Expression of 13 PIP genes was quantified by qRT-PCR in A. thaliana. Among them, only PIP2;3 transcript level was transiently increased when the temperature raised to 36 degrees. The increased level of mRNA was rapidly decreased even at high temperatures within 2 hr. We estimate that this transient alteration of PIP2;3 is tightly related to initial response of heat stress. The total protein level of PIP2s, which was determined immunochemically, was also increased and then decreased in response to heat treatment similarly to the mRNA alteration. The results suggest that high temperatures induce both the transcription and translation of PIP2;3. We also report promoter-GUS analysis and physiological properties of PIP2;3 knockout lines under heat stress.
