Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content

Identification of microRNAs in developing wheat grain that are potentially involved in regulating grain characteristics and the response to nitrogen levels

“…Nitrogen plays an important role in plant growth and agricultural production [24,26], and N fertilization is an effective agronomic practice to increase wheat grain yield and improve grain processing quality [27,28]. Here, HN treatment resulted in higher grain yields, protein content and dough development time, which is consistent with the results of previous reports [27,28,37].…”

“…Nitrogen plays an important role in plant growth and agricultural production [24,26], and N fertilization is an effective agronomic practice to increase wheat grain yield and improve grain processing quality [27,28]. Here, HN treatment resulted in higher grain yields, protein content and dough development time, which is consistent with the results of previous reports [27,28,37]. We also observed that the gluten (gliadin and glutenin) content (27.80 mg g −1 ) increased more than did the albumin and globulin content (9.74 mg g −1 ) under HN treatment, indicating different responses of the grain protein component to N fertilizer.…”

“…In China, applying N fertilizer is an important agronomic practices to increase crop yield and economic productivity [26]. In addition to its effect on yield, N fertilizer is one of the key agronomic means of increasing grain protein content and improving wheat grain quality [27,28]. However, excessive applications of N fertilizer have resulted in environmental pollution [29] and soil acidification [30].…”

Cisgenic overexpression of cytosolic glutamine synthetase improves nitrogen utilization efficiency in barley and prevents grain protein decline under elevated CO2

“…This may be the case even though down‐regulation of GS1 expression under CO 2 enrichment has been reported for different TaGS1 isogenes in wheat (Buchner et al ., ; Vicente et al ., , ), possibly reflecting a decrease in NH 4 + (El Omari et al ., ; Funayama et al ., ; Goodall et al ., ; Guan et al ., ; Konishi et al ., ). The results for the cisgenic lines corroborate the importance of GS1 in maintaining grain protein concentration, as has also been highlighted through identification of QTLs in barley (Fan et al ., ) and via a positive correlation between GS activity and grain protein content in wheat cultivars (Nigro et al ., ; Zhang et al ., ). Considering the fact that extra N supply cannot offset the decline in grain protein concentration of wheat plants growing in an elevated CO 2 environment (Tausz et al ., ; Walker et al ., ), overexpression of HvGS1‐1 may thus provide a means to prevent declining grain protein concentration under elevated atmospheric CO 2 .…”

“…Studies of quantitative trait loci have indicated that the barley HvGS1-1 gene is associated with grain protein concentration (Jukanti and Fischer, 2008), while the maize orthologues ZmGln1-3 and ZmGln1-4 are associated with kernel weight and grain yield, respectively (Gallais and Hirel, 2004). A positive correlation between grain protein concentration, GS (GS1 and GS2) gene expression and GS activity in durum wheat (Triticum durum L.) were reported by Nigro et al (2016) and Zhang et al (2017).…”