Low Nitrogen Stress Promotes Root Nitrogen Uptake and Assimilation in Strawberry: Contribution of Hormone Networks

Abstract

Low nitrogen stress severely impedes crop growth and productivity. There has been substantial research on root adaptation to low nitrogen conditions in many plant species. However, the mechanism underlying the morphological response of the strawberry (Fragaria × ananassa Duch.) root to low-NO3− or low-NH4+ stress remains poorly understood. Strawberry plants were hydroponically cultivated under 1 mM NO3−, 1 mM NH4+, and control (15 mM NO3−) conditions to assess the physiological responses of their roots to low nitrogen stress. As a result, low nitrogen stresses increased the fresh weight of root, lateral root density, and root surface area, as well as enhanced the accumulation of indole-3-acetic acid and jasmonic acid while significantly reducing salicylic acid in the roots. Correspondingly, low nitrogen stresses increased PM H+-ATPase activity. Low-NO3− stress enhanced the activities of nitrate reductase and glutamine synthetase, whereas low-NH4+ treatment led to higher glutamine synthetase and glutamate synthase activities. Collectively, the present results demonstrate that low nitrogen stresses enhance nitrogen uptake of strawberry roots by regulating hormones (indole-3-acetic acid, jasmonic acid, and salicylic acid) and thereby mediating PM H+-ATPase activity, while promoting nitrogen metabolism by upregulating the activities of nitrate reductase, glutamine synthetase, and glutamate synthase. In conclusion, low nitrogen conditions may facilitate more efficient acquisition of available N from the soil by strawberry root system.

Genome-wide analysis of transmembrane 9 superfamily genes in wheat (Triticum aestivum) and their expression in the roots under nitrogen limitation and Bacillus amyloliquefaciens PDR1 treatment conditions

“…After treatment with nitrogen limitation conditions, upregulation in the expression of TraesTM9SF genes was observed, indicating that these genes are responsive to nitrogen limitation. Thus, TraesTM9SF genes may play an important role in the mechanisms underlying the effect of nitrogen limitation on wheat, for example, nitrogen uptake, conversion, or recycling processes, which are needed for nutrient homeostasis and maintenance of plant growth under reduced nitrogen availability ( Masclaux-Daubresse et al., 2010 ; Muratore et al., 2021 ; Zhang et al., 2023 ). Interestingly, the potential role of the alterations of TraesTM9SF genes due to a lack of nitrogen in increasing wheat resistance to nutrient stress, as well as optimizing nitrogen use for increased crop growth and productivity is apparent from the observations of this study.…”

Bicarbonate-Dependent Detoxification by Mitigating Ammonium-Induced Hypoxic Stress in Triticum aestivum Root

“…Ammonium (NH 4 + ) and nitrate (NO 3 − ) are the two main N sources for plants [4][5][6]. NH 4 + can be more directly assimilated by plant cells, while NO 3 − uptake and reduction (i.e., conversion of NO 3 − to NH 4 + via the actions of nitrate reductase and nitrite reductase) consume large amounts of ATP and reducing equivalents, and the resulting NH 4 + is then used by plants [5,7,8]. Therefore, it is widely acknowledged that NH 4 + is the preferred N source with respect to energy cost.…”

“…Therefore, it is widely acknowledged that NH 4 + is the preferred N source with respect to energy cost. To increase crop yields, farmers tend to apply excessive N fertilizers; however, only 30-40% of the fertilizer is estimated to be taken up by plant roots [8,9]. Moreover, excess N fertilizer application often suppresses crop growth, decreases kernel yield, and causes environmental pollution [10].…”