The Thellungiella salsuginea Tonoplast Aquaporin TsTIP1;2 Functions in Protection Against Multiple Abiotic Stresses

Abstract

Examination of aquaporin (AQP) membrane channels in extremophile plants may increase our understanding of plant tolerance to high salt, drought or other conditions. Here, we cloned a tonoplast AQP gene (TsTIP1;2) from the halophyte Thellungiella salsuginea and characterized its biological functions. TsTIP1;2 transcripts accumulate to high levels in several organs, increasing in response to multiple external stimuli. Ectopic overexpression of TsTIP1;2 in Arabidopsis significantly increased plant tolerance to drought, salt and oxidative stresses. TsTIP1;2 had water channel activity when expressed in Xenopus oocytes. TsTIP1;2 was also able to conduct H₂O₂ molecules into yeast cells in response to oxidative stress. TsTIP1;2 was not permeable to Na(+) in Xenopus oocytes, but it could facilitate the entry of Na(+) ions into plant cell vacuoles by an indirect process under high-salinity conditions. Collectively, these data showed that TsTIP1;2 could mediate the conduction of both H₂O and H₂O₂ across membranes, and may act as a multifunctional contributor to survival of T. salsuginea in highly stressful habitats.

A ginseng PgTIP1 gene whose protein biological activity related to Ser128 residue confers faster growth and enhanced salt stress tolerance in Arabidopsis

“…Nevertheless, the transgene also had beneficial effects on plant growth and fruit yield under both control and water stress conditions [8]. The overexpression of TsTIP1;2 enhanced tolerance to drought, salt and oxidative stresses in transgenic Arabidopsis [33]. These studies suggested that TIPs play an important role in controlling plant physiology both under normal and stress conditions.…”

Aquaporins are major determinants of water use efficiency of rice plants in the field

“…Evidence from numerous studies involving quantifying aquaporin expression and overexpression and/or down-regulation of aquaporin genes strongly supports a prominent role in increasing water permeability of different tissues in rice [36][37][38][39] and other plants [34,40,41]. However, the drought tolerance of transgenic plants overexpressing aquaporin genes varied where it increased in some cases [34,38,42] but was not affected or even decreased in some others [43,44].…”

“…Nonetheless, PIP1 aquaporins have been suggested to form heterotetramers with PIP2s with increased water transport activity [31,32]. Some aquaporins have been reported to transport other physiologically important small molecules such as CO 2 [33], boron or silicon [25] or H 2 O 2 [34].…”

Multifaceted roles of aquaporins as molecular conduits in plant responses to abiotic stresses

“…Using the yeast model, H 2 O 2 transport ability of TsTIP1;2 was also confirmed. Thus, TsTIP1;2 might improve H 2 O 2 -mediated long-distance signal transfer which led to the induction of multiple stress tolerance (Wang et al, 2014). Besides TIPs, different PIPs have also been used to enhance plant's stress tolerance in different plants, such as banana (Musa spp.)…”