Drought-Induced Responses of Nitrogen Metabolism in Ipomoea batatas

Abstract

This study investigated the effect of water stress, simulated by the polyethylene glycol (PEG-6000) method, on nitrogen (N) metabolism in leaves and roots of hydroponically grown sweet potato seedlings, Xushu 32 (X32) and Ningzishu 1 (N1). The concentrations of PEG-6000 treatments were 0%, 5% and 10% (m/v). The results showed that the drought-treated plants showed a decline leaf relative water content, and revealed severe growth inhibition, compared with the 0% treatment. Under drought stress, the decline in biomass of the leaf and stem was more noticeable than in root biomass for X32, leading to a higher root to shoot ratio. Drought stress increased the nitrate nitrogen (NO3−-N) and protein in leaves, but reduced all the activities of N-metabolism enzymes and the transcriptional levels of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT); in roots, NO3−-N and NR had opposite trends. The leaf ammonium nitrogen (NH4+-N), GS and amino acid had different trends between X32 and N1 under drought stress. Furthermore, the transcriptional level of nitrate transporter genes NRT1.1 in leaves and roots were upregulated under drought stress, except in N1 roots. In conclusion, NR determined the different response to drought in leaves for X32 and N1, and GS and GOGAT determined the response to drought in roots, respectively.

Effect of drought and waterlogging on saccharides and amino acids content in potato tubers

“…Valfi and Marabel (drought tolerant) (Figure 2E). Such a trend could be related to the decrease of enzymes glutamine synthetase (GS) and glutamate synthase (GOGAT) under DS (Xia et al 2020). l-Asparagine (Asn) increased in cvs.…”

Exogenously Applied Proline Enhances Morph-Physiological Responses and Yield of Drought-Stressed Maize Plants Grown Under Different Irrigation Systems

“…Proline accumulation plays an indispensable role in the regulation of cell osmosis ( El Moukhtari et al, 2020 ). Additionally, under unfavorable conditions of water stress, Pro stabilizes membranes ( Xia et al, 2020 ) and protects enzymes ( Qamar et al, 2019 ; El-Nashaar et al, 2020 ), proteins, and macromolecules from denaturation ( Agami et al, 2019 ). The effectiveness of exogenously applied Pro depends on the plant developmental stage and variety, Pro application rate, and the time of application ( Semida et al, 2020 ).…”

Potassium Fertilization Stimulates Sucrose-to-Starch Conversion and Root Formation in Sweet Potato (Ipomoea batatas (L.) Lam.)

“…The primers of related genes are shown in Supplementary Table S1 . GAPDH was used as a reference gene, and the relative transcriptional levels of Sps , Susy , AGP , SSS34, SSS67, SBEI-1a and SBEII were calculated using the 2 −ΔΔCT method [ 49 , 50 ].…”