State Key Laboratory for Agrobiotechnology, Key Laboratory of Soil Microbiology of Agriculture Ministry and, College of Biological Sciences, China Agricultural University, Haidian District Yuanmingyuan West Road No.2, Beijing, P. R. China.
Chembiochem. 2020 Jun 15;21(12):1717-1722. doi: 10.1002/cbic.201900784. Epub 2020 Mar 2.
Nitrogen is one of the most important nutrients for plant growth. To enhance crop productivity, chemical nitrogen fertilizer is commonly applied in agriculture. Biological nitrogen fixation, the conversion of atmospheric N to NH , is an important source of nitrogen input in agriculture and represents a promising substitute for chemical nitrogen fertilizers. However, nitrogen fixation is only sporadically distributed within bacteria and archaea (diazotrophs). Thus, many biologists hope to reconstitute a nitrogenase biosynthetic pathway in a eukaryotic host, with the final aim of developing N -fixing cereal crops. With the advent of synthetic biology and a deep understanding of the fundamental genetic determinants necessary to sustain nitrogen fixation in bacteria, much progress has been made toward this goal. Transfer of native and refactored nif (nitrogen fixation) genes to non-diazotrophs has been attempted in model bacteria, yeast, and plants. Specifically, nif genes from Klebsiella oxytoca, Azotobacter vinelandii, and Paenibacillus polymyxa have been successfully transferred and expressed in Escherichia coli, Saccharomyces cerevisiae, and even in the tobacco plant. These advances have laid the groundwork to enable cereal crops to "fix" nitrogen themselves to sustain their growth and yield.
氮是植物生长最重要的营养物质之一。为了提高作物产量，农业中通常会施用化学氮肥。生物固氮，即将大气 N 转化为 NH3，是农业中氮素输入的重要来源，也是化学氮肥的一种很有前途的替代品。然而，固氮作用仅在细菌和古菌（固氮菌）中零星分布。因此，许多生物学家希望在真核宿主中重新构建固氮酶生物合成途径，最终目标是开发固氮谷类作物。随着合成生物学的出现以及对维持细菌固氮所需的基本遗传决定因素的深入了解，在这一目标上已经取得了很大进展。已经尝试在模式细菌、酵母和植物中将天然和重构的 nif（氮固定）基因转移到非固氮菌中。具体来说，已经成功地将来自克雷伯氏菌（Klebsiella oxytoca）、维氏固氮菌（Azotobacter vinelandii）和多粘类芽孢杆菌（Paenibacillus polymyxa）的 nif 基因转移并表达在大肠杆菌（Escherichia coli）、酿酒酵母（Saccharomyces cerevisiae）中，甚至在烟草植物中也可以表达。这些进展为使谷类作物能够“自行”固定氮素以维持其生长和产量奠定了基础。
