Abstract:Abstract: Nitrogen is one of the most important elements in agriculture industry. NADP(H)-dependent glu-tamate dehydrogenase (GDH) has a lower affinity for ammonium in higher plants, whose nitrogen is thus mainly assimilated by the glutamine synthetase (GS)/glutamate synthase (GOGAT) pathway. But, in lower organisms such as fungi, GDHs play an important role in nitrogen assimilation due to their higher affinity for am-monium. In this study, a glutamate dehydrogenase gene AbGDH from Alternaria brassicicola was cloned and successfully over-expressed in rice (Oryza sativa L. cv. Kitaake). Enzyme activity assay in vitro demonstrated that the Km values of AbGDH for NH4+, 2-oxoglutarate and glutamate were 2.144±0.141 mmol/L, 2.690±0.233 mmol/L and 96.772±0.542 mmol/L, respectively. Meanwhile, the enzyme activity assay in vivo revealed that, compared with the nontransgenic plants, the AbGDH over-expressing plants showed a higher aminating activity and a lower Km value for NH4+. Additionally, the hydroponic experiments revealed that, compared with control plants, the transgenic seedlings exhibited a significant increase in plant height and dry weight at lower nitrogen conditions. These results suggested that ectopic expression of AbGDH was inclined to convert 2-oxoglutarate to glutamate, which subsequently improved the ammonium assimilation and enhanced the nitrogen use efficiency particularly under low nitrogen fertility.
引用本文:
陈鸣冬, 刘 聪, 刘徳荣, 汤琦龙, 林建中, 刘选明. 异源表达芸薹生链格孢谷氨酸脱氢酶基因AbGDH提高水稻氮素利用率的研究(英文)[J]. 生命科学研究, 2019, 23(1): 1-12.
CHEN Ming-dong, LIU Cong, LIU De-rong, TANG Qi-long, LIN Jian-zhong, LIU Xuan-ming. Ectopic Expression of a Fungal AbGDH Gene from Alternaria brassicicola Improves Nitrogen Use Efficiency in Rice. Life Science Research, 2019, 23(1): 1-12.