Identification of the glutamine synthetase (GS) gene family in four wheat species and functional analysis of Ta4D.GSe in Arabidopsis thaliana

Abstract

Drought stress can negatively impact crop yield and quality. Improving wheat yields under drought stress is a major objective of agronomic research. Glutamine synthetase (GS) is a key enzyme of nitrogen metabolism that is critical to plant growth and development in abiotic stress response. However, to date, no systemic characterization of the GS genes has yet been conducted in wheat and its close relatives. We identified a total of 15 GS genes in Triticum aestivum (2n = 6x = 42; AABBDD), as well as 9 GS genes in Triticum dicoccoides (2n = 4x = 28; AABB), 6 in Aegilops tauschii (2n = 2x = 14; DD), and 5 in Triticum urartu (2n = 2x = 14; AA). The 35 GSs were further clustered into five lineages according to the phylogenetic tree. Synteny analysis revealed that the three subgenomes in bread wheat retained extensive synteny between bread wheat and its three relative species. We identified three up-regulated TaGSs (Ta4A.GSe, Ta4B.GSe, and Ta4D.GSe) from transcriptome data after drought and salt stress. Ta4D.GSe was subsequently used for further functional studies, and its subcellular localization were determined in Arabidopsis protoplasts. Its overexpression in Arabidopsis enhanced drought tolerance by increasing the ability of scavenging of reactive oxygen species (ROS) and osmotic adjustment. We identified GS gene family in four wheat species and performed comparative analyses of their relationships, chromosome locations, conserved motif, gene structure, and synteny. The subcellular localization of Ta4D.GSe was detected and its drought tolerance function was demonstrated. Taken together, these findings provide insight into the potential functional roles of the GS genes in abiotic stress tolerance. Key message This report clearly shows detailed characterization of GS gene family in four wheat species and demonstrates that Ta4D.GSe plays an important role in enhancing drought tolerance by improving the scavenging of ROS and osmotic adjustment ability in Arabidopsis.

Comparison of the transcriptome and metabolome of wheat (Triticum aestivum L.) proteins content during grain formation provides insight

“…Correlation analysis revealed that a total of 25 genes were positively correlated with glutenin, with correlation coefficients ranging from 0.53 to 0.95, and that 20 genes were negatively correlated with glutenin content, with correlation coefficients ranging from 0.50 to 0.95. GS is closely related to the high grain protein content and nitrogen efficiency of wheat, and its activity significantly affects protein and amino acid contents ( Yin et al., 2022 ). The nitrogen absorbed by wheat is catalysed by GS to produce glutamine (Gln) by the ATP-dependent condensation reaction of ammonium with glutamic acid (Glu), which then provides the N group directly through Glu for the biosynthesis of proteins, amino acids, and other nitrogen-containing compounds ( Nigro et al., 2016 ).…”

Genome-Wide Identification and Expression Analysis of Gs and Gogat Gene Family in Pecan (<em>Carya illinoinensis</em>) under Different Nitrogen Forms

“…Studies have shown that the role of GS activity in response to fertilization has been widely investigated, and its relationship with stresses such as drought and high temperature has also been explored [13]. In most plants, GS exists in two forms, including cytoplasmic GS1 and chloroplasts GS2 [14]. In addition, members of the GS gene family have been identified in many plants, such as Arabidopsis (Arabidopsis thaliana (L.) Heynh.)…”