AUTHOR=Secchi Francesca , Zwieniecki Maciej A.

TITLE=The physiological response of Populus tremula x alba leaves to the down-regulation of PIP1 aquaporin gene expression under no water stress

JOURNAL=Frontiers in Plant Science

VOLUME=4

YEAR=2013

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2013.00507

DOI=10.3389/fpls.2013.00507

ISSN=1664-462X

ABSTRACT=<p>In order to study the role of <italic>PIP1</italic> aquaporins in leaf water and CO<sub>2</sub> transport, several lines of <italic>PIP1</italic>-deficient transgenic <italic>Populus tremula x alba</italic> were generated using a reverse genetic approach. These transgenic lines displayed no visible developmental or morphological phenotypes when grown under conditions of no water stress. Major photosynthetic parameters were also not affected by <italic>PIP1</italic> down regulation. However, low levels of <italic>PIP1</italic> expression resulted in greater leaf hydraulic resistance (an increase of 27%), which effectively implicated <italic>PIP1</italic> role in water transport. Additionally, the expression level of <italic>PIP1</italic> genes in the various transgenic lines was correlated with reductions in mesophyll conductance to CO<sub>2</sub> (g<sub>m</sub>), suggesting that in poplar, these aquaporins influenced membrane permeability to CO<sub>2</sub>. Overall, although analysis showed that <italic>PIP1</italic> genes contributed to the mass transfer of water and CO<sub>2</sub> in poplar leaves, their down-regulation did not dramatically impair the physiological needs of this fast growing tree when cultivated under conditions of no stress.</p>