BACKGROUND: Glutamine synthetase (GS) plays a central role in plant nitrogen assimilation. a process intimately linked to soil water availability. We previously showed that hybrid poplar (Populus tremula X alba. INRA 717-1B4) expressing ectopically a pine cytosolic glutamine synthetase gene (GS1a) display enhanced tolerance to drought. https://thebanyantreers.shop/product-category/herb-rub/