Overexpression of an NADP(H)-dependent glutamate dehydrogenase gene, TrGDH, from Trichurus improves nitrogen assimilation, growth status and grain weight per plant in rice
Overexpression of an NADP(H)-dependent glutamate dehydrogenase gene, TrGDH, from Trichurus improves nitrogen assimilation, growth status and grain weight per plant in rice
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Trichurus 的 NADP(H) 依赖性谷氨酸脱氢酶基因 TrGDH 的过度表达可改善水稻的氮同化、生长状态和单株粒重
DOI：
10.1270/jsbbs.19014
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发表时间：
2019-01-01
期刊：
影响因子：
2.4
通讯作者：
Liu, Xuan-Ming
中科院分区：
文献类型：
--
作者：
Du, Chang-Qing;Lin, Jian-Zhong;Liu, Xuan-Ming
由于微生物的谷氨酸脱氢酶（GDH）通常比高等植物的GDH对NH 4+具有更高的亲和力，预期这些GDH的异位表达可以提高高等植物的氮同化。本研究从真菌Trichurus中分离了一个新的NADP（H）-GDH基因（TrGDH），并将其导入水稻（Oryza sativa L.）。体外动力学研究表明，与水稻GDH（OsGDH 4）相比，TrGDH对NH 4+的亲和力更高（Km = 1.48 ± 0.11mM）。NH_4 ~+同化速率测定结果表明，转TrGDH基因株系的NADP（H）-GDH活性显著高于对照株系。水培试验表明，转TrGDH基因植株的鲜重、干重和含氮量均显著增加。田间试验进一步表明，转基因株系的有效穗数、千粒重和单株粒重均显著高于对照，尤其是在低氮水平下。此外，谷蛋白和醇溶谷蛋白在转基因水稻植株的种子中被发现显着增加。这些结果充分证实了TrGDH在水稻中的过表达可以通过增强氮同化作用来改善生长状况和单株粒重。因此，TrGDH是通过基因工程保持作物产量的有希望的候选基因。
As glutamate dehydrogenases (GDHs) of microorganisms usually have higher affinity for NH4+ than do those of higher plants, it is expected that ectopic expression of these GDHs can improve nitrogen assimilation in higher plants. Here, a novel NADP(H)-GDH gene (TrGDH) was isolated from the fungus Trichurus and introduced into rice (Oryza sativa L.). Investigation of kinetic properties in vitro showed that, compared with the rice GDH (OsGDH4), TrGDH exhibited higher affinity for NH4+ (Km = 1.48 ± 0.11 mM). Measurements of the NH4+ assimilation rate demonstrated that the NADP(H)-GDH activities of TrGDH transgenic lines were significantly higher than those of the controls. Hydroponic experiments revealed that the fresh weight, dry weight and nitrogen content significantly increased in the TrGDH transgenic lines. Field trials further demonstrated that the number of effective panicles, 1,000-grain weight and grain weight per plant of the transgenic lines were significantly higher than those of the controls, especially under low-nitrogen levels. Moreover, glutelin and prolamine were found to be markedly increased in seeds from the transgenic rice plants. These results sufficiently confirm that overexpression of TrGDH in rice can improve the growth status and grain weight per plant by enhancing nitrogen assimilation. Thus, TrGDH is a promising candidate gene for maintaining yields in crop plants via genetic engineering.