A Novel Gene Coding γ-Aminobutyric Acid Transporter May Improve the Tolerance of to Adverse Environments.

Novel genes provide important genetic resource for organism innovation. However, the evidence from genetic experiment is limited. In plants, γ-aminobutyric acid (GABA) transporters (GATs) primarily transport GABA and further involve in plant growth, development, and response to various stresses. In this study, we have identified the family in species and characterized their functional evolution and divergence in a desert poplar species (). We found that the underwent genus-specific expansion multiple whole-genome duplications in species. The purifying selection were identified across those evolution and divergence in poplar diversity, except two paralogous and from . The both genes arose from a tandem duplication event about 49 million years ago and have experienced strong positive selection, suggesting that the divergence in PeuGAT3 protein function/structure might define gene function better than in expression pattern. Both genes were functionally characterized in and poplar, respectively. The overexpression of increased the thickness of xylem cells walls in both and poplar and enhanced the lignin content of xylem tissues and the proline accumulation in poplar leaves, all of which may improve tolerance of salt/drought stress in desert poplars. Our findings help clarify the genetic mechanisms underpinning high tolerance in desert poplars and suggest that could be an attractive candidate gene for engineering trees with improved brown-rot resistance.