This study focused on the improvement of nitrogen use efficiency in wheat. The favorable allele of TaGS2-2A in the winter wheat (Triticum aestivum L.) was identified and be cloned for the first time. Inorganic N is assimilated into organic composition is catalysed by glutamine synthetase (GS). TaGS2-2A could help this function. Researchers investigated the gene’s functions and mechanisms in the uptake, transport, assimilation and remobilization of nitrogen. The research results provide valuable gene information for breeding with improved nitrogen use efficiency and yield in wheat.

The representative paper is “Transgenic expression of plastidic glutamine synthetase increases nitrogen uptake and yield in wheat”, published in Plant Biotechnology Journal on March 25, 2018. This journal currently appears in the Chinese Academy of Sciences ranking Q1, and IF:8.154. Hu Mengyun is the first author, Institute for Cereal and Oil Crops of HAAFS is the corresponding unit.

Abstract: The plastidic glutamine synthetase isoform (GS2) plays a key role in nitrogen (N) assimilation. We introduced TaGS2-2Abpro::TaGS2-2Ab, the favorable allele of TaGS2-2A in the winter wheat (Triticum aestivum) variety Ji5265. Transgenic expression of TaGS2-2Ab significantly increased GS2 abundance and GS activity in leaves. Two consecutive field experiments showed the transgenic lines had higher grain yield, spike number, grain number per spike and 1000-grain weight than did the wild type under both low N and high N conditions. Analysis of N use-related traits showed that transgenic expression of TaGS2-2Ab increased root ability to acquire N, N uptake before and after flowering, remobilization of N to grains and N harvest index. Measurement of chlorophyll content and net photosynthesis rate in flag leaves during grain filling stage revealed that the transgenic lines had prolonged leaf functional duration as compared with the wild type. These results suggest that TaGS2 plays important role in N use, and the favorable allele TaGS2-2Ab is valuable in engineering wheat with improved N use efficiency and grain yield.

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Figure 1. Growth performance of the TaGS2-2Ab transgenic lines（GS2-54） and wild control （Kn199，Wt）under High N and low N conditions.