Drought stress can significantly affect plant growth and agricultural productivity. Thus, it is essential to explore and identify the optimal genes for the improvement of crop drought tolerance. Here, a fungal NADP(H)-dependent glutamate dehydrogenase gene (AcGDH) was isolated from Aspergillus candidus, and heterologously expressed in rice. AcGDH has a high affinity for NH₄⁺ and increases the ammonium assimilation in rice. AcGDH transgenic plants exhibited a tolerance to drought and alkali stresses, and their photorespiration was significantly suppressed. Our findings demonstrate that AcGDH alleviates ammonium toxicity and suppresses photorespiration by assimilating excess NH₄⁺ and disturbing the delicate balance of carbon and nitrogen metabolism, thereby improving drought tolerance in rice. Moreover, AcGDH not only improved drought tolerance at the seedling stage but also increased the grain yield under drought stress. Thus, AcGDH is a promising candidate gene for maintaining rice grain yield, and offers an opportunity for improving crop yield under drought stress.

干旱胁迫会严重影响植物生长和农业生产力。因此，必须探索和鉴定用于提高作物抗旱性的最佳基因。在这里，真菌NADP（H）依赖的谷氨酸脱氢酶基因（AcGDH）从曲霉中分离出来，并在水稻中异源表达。AcGDH对NH ₄ ⁺具有很高的亲和力，并增加了水稻中的铵同化作用。AcGDH转基因植物表现出对干旱和碱胁迫的耐受性，并且其光呼吸被显着抑制。我们的发现表明，AcGDH通过吸收过量的NH ₄ ^+可以减轻铵盐毒性并抑制光呼吸。破坏了碳氮代谢的微妙平衡，从而提高了水稻的耐旱性。此外，AcGDH不仅提高了幼苗期的耐旱性，而且提高了干旱胁迫下的籽粒产量。因此，AcGDH是维持水稻籽粒产量的有前途的候选基因，并为干旱胁迫下提高作物产量提供了机会。