Transcription strategies related to photosynthesis and nitrogen metabolism of wheat in response to nitrogen deficiency

Abstract

Background Agricultural yield is closely associated with nitrogen application. Thus, reducing the application of nitrogen without affecting agricultural production remains a challenging task. To understand the metabolic, physiological, and morphological response of wheat (Triticum aestivum) to nitrogen deficiency, it is crucial to identify the genes involved in the activated signaling pathways. Results We conducted a hydroponic experiment using a complete nutrient solution (N1) and a nutrient solution without nitrogen (N0). Wheat plants under nitrogen-deficient conditions (NDC) showed decreased crop height, leaf area, root volume, photosynthetic rate, crop weight, and increased root length, root surface area, root/shoot ratio. It indicates that nitrogen deficiency altered the phenotype of wheat plants. Furthermore, we performed a comprehensive analysis of the phenotype, transcriptome, GO pathways, and KEGG pathways of DEGs identified in wheat grown under NDC. It showed up-regulation of Exp (24), and Nrt (9) gene family members, which increased the nitrogen absorption and down-regulation of Pet (3), Psb (8), Nar (3), and Nir (1) gene family members hampered photosynthesis and nitrogen metabolism. Conclusions We identified 48 candidate genes that were involved in improved photosynthesis and nitrogen metabolism in wheat plants grown under NDC. These genes may serve as molecular markers for genetic breeding of crops.

Impacts of Nitrogen Deficiency on Wheat (Triticum aestivum L.) Grain During the Medium Filling Stage: Transcriptomic and Metabolomic Comparisons

“…These DEGs was previously reported that linked with plastocyanin docking to the PSI complex and carried out effective electron transport (Jensen et al, 2004 ; Khrouchtchova et al, 2005 ). PET family genes were found to be down-regulated in wheat shoot and root under N-starvation conditions to reduce photosynthesis (Xin et al, 2020 ). Photosystem II reaction center complexes such as PSBR protein were down-regulated in wheat seedling (Wang et al, 2019 ) and wheat grain under N stress conditions (Sultana et al, 2020 ).…”

“…Moreover, the weight proportion of fiber content in total sugars of the N0 bran fraction and white flour was 18.9 and 12.2%, respectively, which was higher than that of the Nck bran fraction (18.21%) and white flour (9.21%) ( Figure 2 ); these data indicated that fiber content in endosperm was significantly increased under N0 conditions. Previous studies have stated that the extensibility of the cell wall can be increased by the overexpression of expansin genes in wheat roots to increase N absorption efficiency under low-N stress conditions (Xin et al, 2020 ). The cell wall was shown to thicken and had a higher galactose content following N stress in Arabidopsis (Chrost et al, 2007 ; Pandey et al, 2017 ).…”

“…Wheat has developed many mechanisms to facilitate tolerance to N deficiency, such as enhancing nucleotide metabolism, nitrogen and sulfate transport, and steroid biosynthesis (Guo et al, 2014 ; Sultana et al, 2020 ; Xin et al, 2020 ). Here, the up-regulation of SMC6B, BRCA1, BARD1 , and FAS2 likely facilitates the repair of double-stranded DNA breaks via homologous recombination.…”

“…The last two decades have delivered tremendous progress in understanding the yield, quality, genetic regulations of NUE, as well as the morphological, physiological, and biochemical effects of N deficiency. However, these studies mainly focused on roots and leaves in bread wheat seedlings (Wang et al, 2019 ; Xin et al, 2020 ), or only investigated the transcriptome response to N-starvation (Sultana et al, 2020 ) or metabolome response to high-N condition (Zhen et al, 2016 ) of bread wheat in filling grain. Furthermore, the variation in gene expressions and metabolite levels at the medium stage of grain filling changed to the greatest degree and closely influenced the yield and quality of grain (Zhen et al, 2016 ; Henry et al, 2018 ).…”

Transcriptome Analysis Reveals Different Responsive Patterns to Nitrogen Deficiency in Two Wheat Near-Isogenic Lines Contrasting for Nitrogen Use Efficiency

“…This technique has been employed broadly in various crop species. For instance, Liu et al [ 22 ] employed RNA-seq to analyze transcriptomic changes in wheat under N-deficient conditions and identified new candidate genes, which can directly promote wheat growth. In another study, Wei et al [ 23 ] performed a transcriptome analysis of the leaf and identified key genes related to the metabolism of carbon and nitrogen in rice seedlings under different N treatments.…”