scholarly journals Microstructural and physiological responses to cadmium stress under different nitrogen levels in Populus cathayana females and males

2020 ◽  
Vol 40 (1) ◽  
pp. 30-45 ◽  
Author(s):  
Miao Liu ◽  
Jingwen Bi ◽  
Xiucheng Liu ◽  
Jieyu Kang ◽  
Helena Korpelainen ◽  
...  
Keyword(s):  
Nitrogen Deficiency ◽  
Ion Homeostasis ◽  
N Availability ◽  
Cd Stress ◽  
Cd Accumulation ◽  
N Supply ◽  
Populus Cathayana ◽  
N Deficiency ◽  
Cellular Compartments ◽  
Cd Translocation

Abstract Although increasing attention has been paid to the relationships between heavy metal and nitrogen (N) availability, the mechanism underlying adaptation to cadmium (Cd) stress in dioecious plants has been largely overlooked. This study examined Cd accumulation, translocation and allocation among tissues and cellular compartments in Populus cathayana Rehder females and males. Both leaf Cd accumulation and root-to-shoot Cd translocation were significantly greater in females than in males under a normal N supply, but they were reduced in females and enhanced in males under N deficiency. The genes related to Cd uptake and translocation, HMA2, YSL2 and ZIP2, were strongly induced by Cd stress in female roots and in males under a normal N supply. Cadmium largely accumulated in the leaf blades of females and in the leaf veins of males under a normal N supply, while the contrary was true under N deficiency. Furthermore, Cd was mainly distributed in the leaf epidermis and spongy tissues of males, and in the leaf palisade tissues of females. Nitrogen deficiency increased Cd allocation to the spongy tissues of female leaves and to the palisade tissues of males. In roots, Cd was preferentially distributed to the epidermis and cortices in both sexes, and also to the vascular tissues of females under a normal N supply but not under N deficiency. These results suggested that males possess better Cd tolerance compared with females, even under N deficiency, which is associated with their reduced root-to-shoot Cd translocation, specific Cd distribution in organic and/or cellular compartments, and enhanced antioxidation and ion homeostasis. Our study also provides new insights into engineering woody plants for phytoremediation.

scholarly journals Cadmium uptake, translocation, and redistribution affect Cd accumulation in grain of common wheat (Triticum aestivum L.) cultivars

2020 ◽  
Author(s):  
Yiran Cheng ◽  
Xu Zhang ◽  
Sha Wang ◽  
Xue Xiao ◽  
Jian Zeng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Translocation Factor ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Cd Stress ◽  
Cd Uptake ◽  
Cd Accumulation ◽  
Flag Leaves ◽  
Physiological Processes ◽  
Cd Translocation

Abstract Background To study the cadmium (Cd) accumulation in wheat grain, we evaluated the grain Cd concentrations of 46 common wheat cultivars grown at two sites in Sichuan, China and selected five different grain Cd accumulators (a high-Cd accumulator ZM18, four low-Cd accumulators YM51, YM53, SM969 and CM104) to explore the physiological processes of Cd accumulation in the grain of wheat grown under varying degrees of Cd stress. Results Our results showed that the Cd concentration in grain differed among genotypes. Under low-Cd stress, the grain Cd concentration was correlated with the Cd translocation factor (TF) of roots to grain and all the Cd redistribution factors (RFs). Compared with the ZM18, the cultivars YM53 and SM969 accumulated less Cd in the grain due to low Cd redistribution from lower stems and older leaves to grain. The low-Cd accumulators YM51 and CM104 were due to low Cd transport from roots to grain, and low Cd redistribution from glumes, flag leaves, lower stems, and older leaves to grain. Under high-Cd stress, the ZM18, YM53, and SM969 accumulated significantly more Cd in the grain, root and other tissues than did YM51 and CM104. Correlation analyses showed that the grain Cd concentration of wheat under high Cd stress was positively correlated with the Cd concentration in each tissue and the TFs of roots to grains, rachis, internode 1 and flag leaves. Conclusions Cd translocation directly from roots to grain and Cd redistribution from shoots to grain determines the Cd accumulation in grain of wheat cultivars under low-Cd stress. Cd uptake by root and then synchronously transported to new shoots determined the differences of Cd accumulation in the grain of wheat cultivars under high Cd stress.

scholarly journals Activation of MAPK signaling pathway during nitrogen-deficiency responses in Ulva Prolifera

2020 ◽  
Author(s):  
Juanjuan Yang ◽  
Yi Yin ◽  
Dachun Yu ◽  
Lihong He ◽  
Shan Lu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Nitrogen Deficiency ◽  
Mapk Signaling ◽  
Ulva Prolifera ◽  
N Availability ◽  
Nitrogen Deprivation ◽  
Cell Wall Regeneration ◽  
Green Tides ◽  
Wall Regeneration ◽  
N Deficiency

Abstract Background: Ulva prolifera is one of the main seaweeds (or macroalgae) species that causes “green tides”. This alga inhabits the estuarine areas that exhibit changes in nutrient contents, which include changes in nitrogen (N) levels, while the mechanisms through which these microalgae resist N deficiency remains unclear. Results: We amplified the full-length sequences and quantified expression of genes involved in the nitrogen metabolism process, the data indicated that nitrate reductase, nitrite reductase, and glutamine synthase increased after nitrogen deprivation in Ulva prolifera. Hence, although the ratio of cell-wall regeneration did not change, the apoptosis rates of protoplasts of Ulva prolifera increased after this deficiency. Furthermore, a decreased in N supplies triggered the activation of MAPK signaling, and SB239063, a p38 MAPKα/β inhibitor, enhanced the effects of N deficiency on the mortality of protoplasts and decreased the capacity for cell-wall regeneration. Conclusions: All the data provided evidence that MAPK signaling had functional roles in helping U. prolifera adapt to fluctuations in N availability within a short time. Hence, the application of biochemical reagents on cell-wall regeneration on the surface of protoplasts provided a new perspective in the genetic breeding of Ulva prolifera.

scholarly journals Growth and Physiological Response to Nitrogen Deficiency and Re-supply in Leaf-vegetable Sweetpotato (Ipomoea batatas Lam)

HortScience ◽  
2015 ◽  
Vol 50 (5) ◽  
pp. 754-758 ◽  
Author(s):  
Meng Wei ◽  
Aijun Zhang ◽  
Hongmin Li ◽  
Zhonghou Tang ◽  
Xiaoguang Chen
Keyword(s):  
Amino Acids ◽  
Ipomoea Batatas ◽  
Nitrogen Deficiency ◽  
Essential Amino Acids ◽  
N Availability ◽  
Leaf Color ◽  
Growth Physiology ◽  
Vine Growth ◽  
N Deficiency ◽  
Leaf Vegetable

Nitrogen (N) is an essential macronutrient limiting plant growth and quality of leaf-vegetable sweetpotato (Ipomoea batatas Lam). The objective of this study was to investigate the effects of N deficiency and re-supply on growth, physiology, and amino acids in sweetpotato. Two leaf-vegetable sweetpotato cultivars, Pushu 53 and Tainong 71, were subjected to three treatments in hydro-culture: 1) N sufficiency, 2) N deficiency, and 3) N deficiency and subsequently with N re-supply. Compared with N sufficiency, N deficiency caused a decrease in vine growth, carotenoid and chlorophyll content (Chlt), root viability, photosynthesis, and nitrate reductase (NR) activity in both cultivars, but to a great extent in Tainong 71. Whereas N deficiency increased root growth and glutamine synthetase (GS) activity in both cultivars, and the increase in ‘Tainong 71’ was more obvious. Re-supply of N recovered the vine growth, root viability, Chlt, photosynthesis, NR, and GS activity, to a greater extent for ‘Pushu 53’ than for ‘Tainong 71’. N deficiency significantly decreased essential amino acids, including lysine, phenylalanince, isoleucine, tryptophane, leucine, and valine contents and nonessential amino acids, consisting of glutamic acid, aspartic acid, glycine, argnine, and proline content in both cultivars. These results indicated that the light leaf color leafy sweetpotato ‘Tainong 71’ is sensitive to the N availability and the dark green leaf color ‘Pushu 53’ is more tolerant to low N, which appear to reflect the differential response of two cultivars to their different adaptability to N availability.

Nitrogen deficiency precludes a growth response to CO2 enrichment in C3 and C4 Panicum grasses

1998 ◽  
Vol 25 (5) ◽  
pp. 627 ◽  
Author(s):  
Oula Ghannoum ◽  
Jann P. Conroy
Keyword(s):  
Growth Response ◽  
Nitrogen Deficiency ◽  
Co2 Enrichment ◽  
Biomass Accumulation ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Initial Slope ◽  
Co2 Response ◽  
N Supply ◽  
N Deficiency

We investigated the interaction of nitrogen (N) supply and CO2 enrichment on the growth and photosynthesis of Panicum laxum (C3), P. coloratum (C4) and P. antidotale (C4). Plants were grown at ambient CO2 partial pressures (pa) of either 36 (low) or 71 (high) Pa, in potted soil supplied with 0 (low) or 60 (high) mg N kg-1 soil week-1. Elevated CO2 enhanced total plant dry mass of all three species by approximately 28% under high N supply, but had no effect on biomass accumulation under N deficiency. CO2 enrichment resulted in reductions of CO2 assimilation rates (A; measured at comparable pa) of P. laxum, indicating acclimation of photosynthesis. This acclimation, which was more pronounced under N stress, was unrelated to changes in leaf N or non-structural carbohydrate concentrations, because neither were affected by CO2 enrichment. In the C4 grasses grown at low N, A were fully saturated at the current ambient pa, whereas at high N, A increased slightly when CO2 was raised to 71 Pa. N deficiency reduced the initial slope of the CO2 response curve of A in P. antidotale, and this effect was more pronounced at high CO2. In conclusion, the preclusion of a growth response to CO2 enrichment by N deficiency was correlated with a strong inhibition of A in the C3 species, and the saturation of A at below current atmospheric pa in C4 species.

scholarly journals Overexpression of the manganese/cadmium transporter OsNRAMP5 reduces cadmium accumulation in rice grain

2020 ◽  
Vol 71 (18) ◽  
pp. 5705-5715 ◽  
Author(s):  
Jia-Dong Chang ◽  
Sheng Huang ◽  
Noriyuki Konishi ◽  
Peng Wang ◽  
Jie Chen ◽  
...  
Keyword(s):  
Lateral Root ◽  
Ion Homeostasis ◽  
Toxic Metal ◽  
Rice Grain ◽  
Wild Type ◽  
Root Tips ◽  
Root Primordia ◽  
Lateral Root Primordia ◽  
Cd Accumulation ◽  
Cd Translocation

Abstract Rice is a major dietary source of the toxic metal cadmium (Cd), and reducing its accumulation in the grain is therefore important for food safety. We selected two cultivars with contrasting Cd accumulation and generated transgenic lines overexpressing OsNRAMP5, which encodes a major influx transporter for manganese (Mn) and Cd. We used two different promoters to control the expression, namely OsActin1 and maize Ubiquitin. Overexpression of OsNRAMP5 increased Cd and Mn uptake into the roots, but markedly decreased Cd accumulation in the shoots, whilst having a relatively small effect on Mn accumulation in the shoots. The overexpressed OsNRAMP5 protein was localized to the plasma membrane of all cell types in the root tips and lateral root primordia without polarity. Synchrotron X-ray fluorescence mapping showed that the overexpression lines accumulated more Cd in the root tips and lateral root primordia compared with the wild-type. When grown in three Cd-contaminated paddy soils, overexpression of OsNRAMP5 decreased concentration of Cd in the grain by 49–94% compared with the wild type. OsNRAMP5-overexpression plants had decreased Cd translocation from roots to shoots as a result of disruption of its radial transport into the stele for xylem loading, demonstrating the effect of transporter localization and polarity on ion homeostasis.

Sexually differential gene expressions in poplar roots in response to nitrogen deficiency

2019 ◽  
Vol 39 (9) ◽  
pp. 1614-1629 ◽  
Author(s):  
Haifeng Song ◽  
Zeyu Cai ◽  
Jun Liao ◽  
Duoteng Tang ◽  
Sheng Zhang
Keyword(s):  
Gene Expression ◽  
Nitrogen Deficiency ◽  
Production Costs ◽  
Molecular Evidence ◽  
Male And Female ◽  
Resistance Strategies ◽  
N Limitation ◽  
Populus Cathayana ◽  
Differential Gene ◽  
N Deficiency

Abstract Nitrogen (N) is a key nutrient impacting plant growth and physiological processes. However, the supply of N is often not sufficient to meet the requirements of trees in many terrestrial ecosystems. Because of differences in production costs, male and female plants have evolved different stress resistance strategies for N limitation. However, little is known about differential gene expression according to sex in poplars responding to N limitation. To explore sex-related constitutive defenses, Populus cathayana Rehder transcriptomic, proteomic and metabolic analyses were performed on the roots of male and female Populus cathayana. We detected 16,816 proteins and 37,286 transcripts, with 2797 overlapping proteins and mRNAs in the roots. In combination with the identification of 90 metabolites, we found that N deficiency greatly altered gene expression related to N metabolism as well as carbohydrate metabolism, secondary metabolism and stress-related processes in both sexes. Nitrogen-deficient P. cathayana females exhibited greater root biomass and less inhibition of citric acid production and glycolysis as well as higher secondary metabolic activity and abscisic acid contents than N-deficient P. cathayana males. Interestingly, males presented a better osmotic adjustment ability and higher expression of resistance genes, suggesting that P. cathayana males exhibit a better stress tolerance ability and can invest fewer resources in defense compared with females. Therefore, our study provides new molecular evidence that P. cathayana males and females adopt different resistance strategies to cope with N deficiency in their roots.

scholarly journals Optimal Nitrogen Supply Ameliorates the Performance of Wheat Seedlings under Osmotic Stress in Genotype-Specific Manner

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 493 ◽  
Author(s):  
Tania Kartseva ◽  
Anelia Dobrikova ◽  
Konstantina Kocheva ◽  
Vladimir Alexandrov ◽  
Georgi Georgiev ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Stress Tolerance ◽  
Wheat Variety ◽  
Growth And Yield ◽  
Physiological Status ◽  
Wheat Seedlings ◽  
Modern Variety ◽  
N Supply ◽  
N Assimilation ◽  
N Deficiency

Strategies and coping mechanisms for stress tolerance under sub-optimal nutrition conditions could provide important guidelines for developing selection criteria in sustainable agriculture. Nitrogen (N) is one of the major nutrients limiting the growth and yield of crop plants, among which wheat is probably the most substantial to human diet worldwide. Physiological status and photosynthetic capacity of two contrasting wheat genotypes (old Slomer and modern semi-dwarf Enola) were evaluated at the seedling stage to assess how N supply affected osmotic stress tolerance and capacity of plants to survive drought periods. It was evident that higher N input in both varieties contributed to better performance under dehydration. The combination of lower N supply and water deprivation (osmotic stress induced by polyethylene glycol treatment) led to greater damage of the photosynthetic efficiency and a higher degree of oxidative stress than the individually applied stresses. The old wheat variety had better N assimilation efficiency, and it was also the one with better performance under N deficiency. However, when both N and water were deficient, the modern variety demonstrated better photosynthetic performance. It was concluded that different strategies for overcoming osmotic stress alone or in combination with low N could be attributed to differences in the genetic background. Better performance of the modern variety conceivably indicated that semi-dwarfing (Rht) alleles might have a beneficial effect in arid regions and N deficiency conditions.

scholarly journals Integrative Transcriptomic and Proteomic Analysis Reveals an Alternative Molecular Network of Glutamine Synthetase 2 Corresponding to Nitrogen Deficiency in Rice (Oryza sativa L.)

2021 ◽  
Vol 22 (14) ◽  
pp. 7674
Author(s):  
Ting Liang ◽  
Zhengqing Yuan ◽  
Lu Fu ◽  
Menghan Zhu ◽  
Xiaoyun Luo ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Oryza Sativa L ◽  
Alternative Pathway ◽  
Rice Variety ◽  
Nitrogen Deficiency ◽  
Primary Root ◽  
Phenotypic Characterization ◽  
Glutathione Metabolism ◽  
N Assimilation ◽  
N Deficiency

Nitrogen (N) is an essential nutrient for plant growth and development. The root system architecture is a highly regulated morphological system, which is sensitive to the availability of nutrients, such as N. Phenotypic characterization of roots from LY9348 (a rice variety with high nitrogen use efficiency (NUE)) treated with 0.725 mM NH4NO3 (1/4N) was remarkable, especially primary root (PR) elongation, which was the highest. A comprehensive analysis was performed for transcriptome and proteome profiling of LY9348 roots between 1/4N and 2.9 mM NH4NO3 (1N) treatments. The results indicated 3908 differential expression genes (DEGs; 2569 upregulated and 1339 downregulated) and 411 differential abundance proteins (DAPs; 192 upregulated and 219 downregulated). Among all DAPs in the proteome, glutamine synthetase (GS2), a chloroplastic ammonium assimilation protein, was the most upregulated protein identified. The unexpected concentration of GS2 from the shoot to the root in the 1/4N treatment indicated that the presence of an alternative pathway of N assimilation regulated by GS2 in LY9348 corresponded to the low N signal, which was supported by GS enzyme activity and glutamine/glutamate (Gln/Glu) contents analysis. In addition, N transporters (NRT2.1, NRT2.2, NRT2.3, NRT2.4, NAR2.1, AMT1.3, AMT1.2, and putative AMT3.3) and N assimilators (NR2, GS1;1, GS1;2, GS1;3, NADH-GOGAT2, and AS2) were significantly induced during the long-term N-deficiency response at the transcription level (14 days). Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis demonstrated that phenylpropanoid biosynthesis and glutathione metabolism were significantly modulated by N deficiency. Notably, many transcription factors and plant hormones were found to participate in root morphological adaptation. In conclusion, our study provides valuable information to further understand the response of rice roots to N-deficiency stress.

scholarly journals Physiological and Proteomic Dissection of the Responses of Two Contrasting Wheat Genotypes to Nitrogen Deficiency

2020 ◽  
Vol 21 (6) ◽  
pp. 2119 ◽  
Author(s):  
Mohammad Rezaul Karim ◽  
Ruonan Wang ◽  
Lu Zheng ◽  
Xiaoying Dong ◽  
Renfang Shen ◽  
...  
Keyword(s):  
Aluminum Toxicity ◽  
Nitrogen Deficiency ◽  
Differentially Expressed Proteins ◽  
Sulfate Assimilation ◽  
Label Free ◽  
Proteomics Analysis ◽  
Tetrapyrrole Synthesis ◽  
Adaptive Processes ◽  
Physiological Indexes ◽  
N Deficiency

Nitrogen deficiency usually occurs along with aluminum toxicity in acidic soil, which is one of the major constraints for wheat production worldwide. In order to compare adaptive processes to N deficiency with different Al-tolerant wheat cultivars, we chose Atlas 66 and Scout 66 to comprehensively analyze the physiological responses to N deficiency, coupled with label-free mass spectrometry-based proteomics analysis. Results showed that both cultivars were comparable in most physiological indexes under N deficient conditions. However, the chlorophyll content in Scout 66 was higher than that of Atlas 66 under N deficiency. Further proteomic analysis identified 5592 and 5496 proteins in the leaves of Atlas 66 and Scout 66, respectively, of which 658 and 734 proteins were shown to significantly change in abundance upon N deficiency, respectively. The majority of the differentially expressed proteins were involved in cellular N compound metabolic process, photosynthesis, etc. Moreover, tetrapyrrole synthesis and sulfate assimilation were particularly enriched in Scout 66. Our findings provide evidence towards a better understanding of genotype-dependent responses under N deficiency which could help us to develop N efficient cultivars to various soil types.

scholarly journals Efficacy of Indole Acetic Acid and Exopolysaccharides-Producing Bacillus safensis Strain FN13 for Inducing Cd-Stress Tolerance and Plant Growth Promotion in Brassica juncea (L.)

2021 ◽  
Vol 11 (9) ◽  
pp. 4160
Author(s):  
Farheen Nazli ◽  
Xiukang Wang ◽  
Maqshoof Ahmad ◽  
Azhar Hussain ◽  
Bushra ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Stress Tolerance ◽  
Brassica Juncea ◽  
Contaminated Soils ◽  
Effective Strain ◽  
Antioxidant Enzyme Activities ◽  
Cd Stress ◽  
Cd Accumulation ◽  
Bacillus Safensis

Untreated wastewater used for irrigating crops is the major source of toxic heavy metals and other pollutants in soils. These heavy metals affect plant growth and deteriorate the quality of edible parts of growing plants. Phytohormone (IAA) and exopolysaccharides (EPS) producing plant growth-promoting rhizobacteria can reduce the toxicity of metals by stabilizing them in soil. The present experiment was conducted to evaluate the IAA and EPS-producing rhizobacterial strains for improving growth, physiology, and antioxidant activity of Brassica juncea (L.) under Cd-stress. Results showed that Cd-stress significantly decreased the growth and physiological parameters of mustard plants. Inoculation with Cd-tolerant, IAA and EPS-producing rhizobacterial strains, however, significantly retrieved the inhibitory effects of Cd-stress on mustard growth, and physiology by up regulating antioxidant enzyme activities. Higher Cd accumulation and proline content was observed in the roots and shoot tissues upon Cd-stress in mustard plants while reduced proline and Cd accumulation was recorded upon rhizobacterial strains inoculation. Maximum decrease in proline contents (12.4%) and Cd concentration in root (26.9%) and shoot (29%) in comparison to control plants was observed due to inoculation with Bacillus safensis strain FN13. The activity of antioxidant enzymes was increased due to Cd-stress; however, the inoculation with Cd-tolerant, IAA-producing rhizobacterial strains showed a non-significant impact in the case of the activity of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in Brassica juncea (L.) plants under Cd-stress. Overall, Bacillus safensis strain FN13 was the most effective strain in improving the Brassica juncea (L.) growth and physiology under Cd-stress. It can be concluded, as the strain FN13 is a potential phytostabilizing biofertilizer for heavy metal contaminated soils, that it can be recommended to induce Cd-stress tolerance in crop plants.

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