Zn-deficient Conditions Research Articles

NtZIP5A/B is involved in the regulation of Zn/Cu/Fe/Mn/Cd homeostasis in tobacco.

Plants grow in soils with varying concentrations of microelements, often in the presence of toxic metals e.g. Cd. To cope, they developed molecular mechanisms to regulate metal cross-homeostasis. Understanding underlying complex relationships is key to improving crop productivity. Recent research suggests that the Zn and Cd uptake protein NtZIP5A/B [Zinc-regulated, Iron-regulated transporter-like Proteins (ZIPs)] from tobacco (Nicotiana tabacum L. v. Xanthi) is involved in the regulation of a cross-talk between the two metals. Here, we support this conclusion by showing that RNAi-mediated silencing of NtZIP5A/B resulted in a reduction of Zn accumulation and that this effect was significantly enhanced by the presence of Cd. Our data also point to involvement of NtZIP5B in regulating a cross-talk between Cu, Fe, and Mn. Using yeast growth assays, Cu (but not Fe or Mn) was identified as a substrate for NtZIP5B. Furthermore, GUS-based analysis showed that the tissue-specific activity of the NtZIP5B promoter was different in each of the Zn-/Cu-/Fe-/Mn deficiencies applied with/without Cd. The results indicate that NtZIP5B is involved in maintaining multi-metal homeostasis under conditions of Zn, Cu, Fe, and Mn deficiency, and also in the presence of Cd. It was concluded that the protein regulates the delivery of Zn and Cu specifically to targeted different root cells depending on the Zn/Cu/Fe/Mn status. Importantly, in the presence of Cd, the activity of the NtZIP5B promoter is lost in meristematic cells and increased in mature root cortex cells, which can be considered a manifestation of a defense mechanism against its toxic effects.

Screening of Bread and Durum Wheat Varieties on Yield and Nutritional Quality for Their Tolerance to Zinc Stress

ABSTRACT Zinc (Zn) deficiency is one of the most prevalent micronutrient deficiencies and is mostly brought on by a diet high in cereal grains with low Zn contents. In order to screen prominent bread (12 varieties) and durum (6 varieties) wheat varieties grown under Zn deficient (control) and sufficient (Zn @ 25 mg kg−1 as soil) condition and a pot experiment was conducted in the screen house of the Department of Soil Science, Chaudhary Charan Singh Haryana Agricultural University, Hisar. In the Zn deficient and sufficient soil, the highest yield was observed in HD-2967 (14.57 & 16.13 g/pot) and PWD-291 (8.68 & 11.70 g/pot) of bread and durum wheat, respectively. In Zn-deficient soil, the highest total protein content and Zn content in grain were observed in DBW-88 (8.17 & 26.50%) and PWD-291 (8.42 & 26.52%) of bread and durum wheat, respectively. All the bread wheat varieties were found to be semi tolerant, i.e. the percentage increase in yield was in the category of 10–25% except WH-52 and RAJ-3765 where increase in yield was more than 25%. The maximum increase in yield was found 28.91% in the WH-542 and the minimum increase (10.70%) in the HD-2967 wheat varieties. For durum wheat, two varieties (WH-912 &WHD-943) were found to be semi tolerant, i.e. the percentage increase in yield was in the category of 10–25%. In conclusion, it was determined that this study is helpful for creating methods for micronutrient biofortification using various wheat varieties in south-central Asia.

Enhancing the growth and zinc efficiency of cherry tomatoes by inoculating endophytic bacteria from zinc hyperaccumulator, Sedum alfredi Hance

Microbial biofertilizers, an innovative and eco-friendly strategy for nutritional improvement, could be utilized for zinc (Zn) efficiency and biofortification. Endophytic bacteria with Zn solubilizing and plant growth-promoting capacities were isolated from hyperaccumulator S. alfredi, and their impacts on the growth and Zn efficiency of cherry tomatoes under Zn-deficiency conditions were investigated. The results showed that most endophytic bacteria promoted the growth of tomato seedlings, while only specific endophytic bacteria played a role in Zn accumulation. Among them, inoculation with SaBA1, SaPS2, SaEN1, and SaPA1 not only significantly increased the fresh weight (FW) of tomato's young leaves by 3.1 to 3.6 times, but also raised the soil available Zn concentration by 0.58–0.92 mg/kg and improved the Zn accumulation in young leaves by 18 % to 30 %. The results indicated that these four bacteria could activate the availability of soil Zn, regulate the distribution of Zn in plants, and enable tomatoes to maintain healthy growth and development under Zn-deficiency conditions. This revealed their immense potential in enhancing crop yield, improving crop Zn nutrition, and boosting crop Zn efficiency.

Arbuscular mycorrhizal fungi induce Zn uptake and antioxidant efficiency in broccoli (Brassica oleracea L.) exposed to Zn deficiency

Zinc (Zn) is an essential micronutrient for plant growth and development, and its deficiency in soil can be a significant problem for broccoli (Brassica oleracea L.) production. While the genetic efforts to breed Zn-efficient broccoli are complex, harnessing microbiomes is an emerging way to induce mineral efficiency in crops. In this study, broccoli, a non-host mycorrhizal species, was cultivated with or without zinc deficiency in the presence or absence of arbuscular mycorrhizal fungi (AMF), confirmed by the colonization efficiency in roots. Zn deficiency caused a significant decrease in morphological parameters and photosynthetic attributes being consistent with the decreased Zn levels in root and shoot relative to Zn-sufficient plants. However, the broccoli plants inoculated with AMF showed a substantial improvement in morphological and photosynthetic parameters in Zn-deficient conditions due to the significant increase in tissue Zn levels. In addition, AMF-inoculated plants under Zn deficiency showed a significant decrease in cell death (%), electrolyte leakage, and H2O2 levels compared to Zn-deficient plants, which further suggests the improvements in cellular status due to the AMF colonization. The real-time PCR experiments showed a significant induction in the expression of BoZIP1 and BoNRAMP1 genes in the roots of Zn-deficient broccoli inoculated with AMF, suggesting that AMF may be associated with the induction of these genes responsible for Zn-uptake and transport. We further observed the induction of POD (peroxidase), APX (ascorbate peroxidase) and SOD (superoxide dismutase), and S-metabolites (cysteine and glutathione) predominantly in the roots of Zn-starved broccoli inoculated with AMF which may confer tolerance to Zn-deficiency induced oxidative damage. This is the first report on the role of AMF in mitigating Zn-deficiency in broccoli which may promote the microbiome-aided improvement in plant health suffering from Zn-deficiency in broccoli and other vegetable crops.

Regulation of metal homoeostasis by two F-group bZIP transcription factors bZIP48 and bZIP50 in rice.

Zinc (Zn) deficiency not only impairs plant growth and development but also has negative effects on human health. Rice (Oryza Sativa L.) is a staple food for over half of the global population, yet the regulation of Zn deficiency response in rice remains largely unknown. In this study, we provide evidence that two F-group bZIP transcription factors, OsbZIP48/50, play a crucial role in Zn deficiency response. Mutations in OsbZIP48/50 result in impaired growth and reduced Zn/Fe/Cu content under Zn deficiency conditions. The N-terminus of OsbZIP48/OsbZIP50 contains two Zn sensor motifs (ZSMs), deletion or mutation of these ZSMs leads to increased nuclear localization. Both OsbZIP48 and OsbZIP50 exhibit transcriptional activation activity, and the upregulation of 1117 genes involved in metal uptake and other processes by Zn deficiency is diminished in the OsbZIP48/50 double mutant. Both OsbZIP48 and OsbZIP50 bind to the promoter of OsZIP10 and activate the ZDRE cis-element. Amino acid substitution mutation of the ZSM domain of OsbZIP48 in OsbZIP50 mutant background increases the content of Zn/Fe/Cu in brown rice seeds and leaves. Therefore, this study demonstrates that OsbZIP48/50 play a crucial role in regulating metal homoeostasis and identifies their downstream genes involved in the Zn deficiency response in rice.

Effects of Individual or Combined Deficiency of Phosphorous and Zinc on Phenotypic, Nutrient Uptake, and Molecular Responses of Finger Millet (Eleusine coracana): A Nutri-Rich Cereal Crop.

Deficiencies of either phosphorus (P) or zinc (Zn) or both are one of the major abiotic constraints influencing agricultural production. Research on the effects of individual or combined P and Zn deficiency is limited in cereals. This study reports the effects of the individual or combined deficiency of inorganic phosphate (Pi) and Zn on the phenotypic, root hair modification, nutrient uptake, and molecular responses of finger millet (Eleusine coracana), a nutri-rich cereal crop. Finger millet seedlings were grown hydroponically under control (+Pi+Zn), individual Pi deficiency (-Pi), individual Zn deficiency (-Zn), and combined Pi and Zn deficiency (-Pi-Zn) conditions for 30 days to find the phenotypic, root hair modification, nutrient uptake, and molecular responses. Compared to the individual -Zn condition, the individual -Pi condition had more of an effect in terms of biomass reduction. The combined -Pi-Zn condition increased the root hair length and density compared to the other three conditions. The individual -Zn condition increased the Pi uptake, while the individual -Pi condition favored the Zn uptake. EcZIP2 was highly upregulated in shoot tissues under the individual -Zn condition, and EcPHT1;2 was highly expressed in root tissues under the individual -Pi condition. This is the first study to report the effects of the individual or combined deficiency of Pi and Zn in finger millet and may lead to future studies to better manage P and Zn deficiency.

ZIP Genes Are Involved in the Retransfer of Zinc Ions during the Senescence of Zinc-Deficient Rice Leaves.

Rice lacks sufficient amounts of zinc despite its vitality for human health. Leaf senescence enables redistribution of nutrients to other organs, yet Zn retransfer during deficiency is often overlooked. In this hydroponic experiment, we studied the effect of Zn deficiency on rice seedlings, focusing on the fourth leaf under control and deficient conditions. Growth phenotype analysis showed that the growth of rice nodal roots was inhibited in Zn deficiency, and the fourth leaf exhibited accelerated senescence and increased Zn ion transfer. Analyzing differentially expressed genes showed that Zn deficiency regulates more ZIP family genes involved in Zn ion retransfer. OsZIP3 upregulation under Zn-deficient conditions may not be induced by Zn deficiency, whereas OsZIP4 is only induced during Zn deficiency. Gene ontology enrichment analysis showed that Zn-deficient leaves mobilized more biological pathways (BPs) during aging, and the enrichment function differed from that of normal aging leaves. The most apparent "zinc ion transport" BP was stronger than that of normal senescence, possibly due to Zn-deficient leaves mobilizing large amounts of BP related to lipid metabolism during senescence. These results provide a basis for further functional analyses of genes and the study of trace element transfer during rice leaf senescence.

Physiological trade-off of marine fish under Zn deficient and excess conditions

Fish can regulate their Zn body bioaccumulation, but the mechanisms and physiological responses at the organ level are still largely unknown. In the present study, we exposed the marine seabreams under different Zn levels (deficient, optimum and excess levels) over a period of 4 weeks and examined how fish maintained its regulation of bioaccumulation with associated physiological effects at the fish intestinal organ. Our results indicated that fish intestinal organs constantly controlled the Zip family to “rob” more Zn under Zn-deficiency (with a dietary level of 7.9 mg/kg), whereas restricted the Zn efflux to preserve the intestinal function. Under Zn-excess conditions (193.3 mg/kg), the fish intestine maintained a limited Zn homeostasis (37.8–44.6 μg/mg) by initially inhibiting the influx through the Zip family receptor, but later accelerating both influx and efflux of Zn. Based on the WGCNA method, Zn deficient dietary exposure first resulted in defense response with subsequent switching to antioxidant defense. Instead, excess Zn first triggered the immunological response, but then led to physiological toxicity (abnormal in lipid metabolism). Although Zn had multiple biological functions, it was preferentially involved in lipid metabolism under different dietary Zn doses. This study provided direct evidence for Zn regulation at the organ level and detoxification mechanisms against potential environmental toxicity in fish.

Zinc deficiency-induced defensin-like proteins are involved in the inhibition of root growth in Arabidopsis.

The depletion of cellular zinc (Zn) adversely affects plant growth. Plants have adaptation mechanisms for Zn-deficient conditions, inhibiting growth through the action of transcription factors and metal transporters. We previously identified three defensin-like (DEFL) proteins (DEFL203, DEFL206 and DEFL208) that were induced in Arabidopsis thaliana roots under Zn-depleted conditions. DEFLs are small cysteine-rich peptides involved in defense responses, development and excess metal stress in plants. However, the functions of DEFLs in the Zn-deficiency response are largely unknown. Here, phylogenetic tree analysis revealed that seven DEFLs (DEFL202-DEFL208) were categorized into one subgroup. Among the seven DEFLs, the transcripts of five (not DEFL204 and DEFL205) were upregulated by Zn deficiency, consistent with the presence of cis-elements for basic-region leucine-zipper 19 (bZIP19) or bZIP23 in their promoter regions. Microscopic observation of GFP-tagged DEFL203 showed that DEFL203-sGFP was localized to the apoplast and plasma membrane. Whereas a single mutation of the DEFL202 or DEFL203 genes only slightly affected root growth, defl202 defl203 double mutants showed enhanced root growth under all growth conditions. We also showed that the size of the root meristem was increased in the double mutants compared with the wild type. Our results suggest that DEFL202 and DEFL203 are redundantly involved in the inhibition of root growth under Zn-deficient conditions through a reduction in root meristem length and cell number.

ZrgA contributes to zinc acquisition in Vibrio parahaemolyticus

ABSTRACT Metals are nutrients essential for almost all lifeforms. Bacteria have evolved several mechanisms to overcome the metal restrictions imposed by the host. Vibrio parahaemolyticus causes severe threats to public health and significant economic losses in shrimp aquaculture. Herein, we report that ZrgA contributes to zinc acquisition in this pathogen. The operon VP_RS01455 to VP_RS01475 of V. parahaemolyticus encodes the putative Zn transporter ZrgABCDE, whose homologs are widely distributed in Vibrionaceae. RNA sequencing analysis revealed that V. parahaemolyticus modulates the transcriptome in response to Zn limitation. Genes in the Zinc uptake regulator (Zur) regulon are upregulated during Zn limitation, including three genes annotated to encode Zn-binding proteins. Significant upregulation of these three genes during Zn limitation was also confirmed by quantitative real-time PCR (qRT-PCR) analysis. However, only the mutants containing a VP_RS01470 (zrgA) deletion exhibited impaired growth under Zn-deficient conditions, indicating that VP_RS01470 plays the predominant role in V. parahaemolyticus Zn acquisition. The VP_RS01470 deletion mutant displayed a false appearance of decreased swimming motility under Zn-deficient conditions, as revealed by the fact that the polar flagellar-related genes were not downregulated in the mutant. Moreover, VP_RS01470 deletion produced no noticeable impact on the swarming motility and virulence in mice. qRT-PCR analysis and β-galactosidase activity assays indicated that Zur negatively regulates VP_RS01470 expression in V. parahaemolyticus. Collectively, our findings suggest that ZrgA is required for Zn acquisition in V. parahaemolyticus and highlight the importance of detecting the expression of flagellar genes during analysis of motility of a mutant deficient in growth.

Identification of Potential Zinc Deficiency Responsive Genes and Regulatory Pathways in Rice by Weighted Gene Co-expression Network Analysis

Zinc (Zn) malnutrition is a major public health issue. Genetic biofortification of Zn in rice grain can alleviate global Zn malnutrition. Therefore, elucidating the genetic mechanisms regulating Zn deprivation response in rice is essential to identify elite genes useful for breeding high grain Zn rice varieties. Here, a meta-analysis of previous RNA-Seq studies involving Zn deficient conditions was conducted using the weighted gene co-expression network analysis (WGCNA) and other in silico prediction tools to identify modules (denoting cluster of genes with related expression pattern) of co-expressed genes, modular genes which are conserved differentially expressed genes (DEGs) across independent RNA-Seq studies, and the molecular pathways of the conserved modular DEGs. WGCNA identified 16 modules of co-expressed genes. Twenty-eight and five modular DEGs were conserved in leaf and crown, and root tissues across two independent RNA-Seq studies. Functional enrichment analysis showed that 24 of the 28 conserved modular DEGs from leaf and crown tissues significantly up-regulated 2 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and 15 Gene Ontology (GO) terms, including the substrate- specific transmembrane transporter and the small molecule metabolic process. Further, the well-studied transcription factors (OsWOX11 and OsbHLH120), protein kinase (OsCDPK20 and OsMPK17), and miRNAs (OSA-MIR397A and OSA-MIR397B) were predicted to target some of the identified conserved modular DEGs. Out of the 24 conserved and up-regulated modular DEGs, 19 were yet to be experimentally validated as Zn deficiency responsive genes. Findings from this study provide a comprehensive insight on the molecular mechanisms of Zn deficiency response and may facilitate gene and pathway prioritization for improving Zn use efficiency and Zn biofortification in rice.

OsNAC15 Regulates Tolerance to Zinc Deficiency and Cadmium by Binding to OsZIP7 and OsZIP10 in Rice.

Zinc (Zn) deficiency and cadmium (Cd) stress are severe threats to the growth and development of plants. Increasing Zn content and/or decreasing Cd content in grain are also important objectives of rice breeding. However, the molecular mechanisms of Zn deficiency tolerance (ZDT) and Cd stress tolerance (CDT) are largely unknown in rice. Here, we report that a NAM/CUC2-like transcription factor, OsNAC15, contributes to ZDT and CDT in rice. Knockout of OsNAC15 reduced ZDT and CDT at the vegetative stage. OsNAC15 expresses in all tissues of different developmental stages, and is repressed by Zn deficiency and induced by Cd stress. OsNAC15 is a functional transcription factor with transactivation and DNA binding activities. Expression analysis of rice ZIP family genes suggested that the knockout of OsNAC15 activates or inhibits their transcriptions under Zn deficiency or Cd stress conditions. The yeast one-hybrid assay, transient transcriptional activity assay using the dual-luciferase reporter system and electrophoretic mobility shift assay demonstrated that OsNAC15 directly binds to the zinc deficiency-responsive element motifs in the promoters of OsZIP7 and OsZIP10 to repress their transcriptions. The OsNAC15–OsZIP7/10 module is an essential foundation for further study on the regulatory mechanisms of ZDT and CDT in rice.

Dietary zinc deficient condition increases the Bisphenol A toxicity in diabetic rat testes.

Bisphenol A (BPA) is a widely used endocrine disrupter that causes male reproductive dysfunction in humans and rodents. Diabetes-induced hyperglycemia alters spermatogenesis and antioxidant status, which negatively impacts male fertility in adults. Zinc (Zn) deficiency is a global health concern maintaining the testicular structure and functions in developing gonads. The present experiment was designed to investigate the role of Zn deficiency on BPA-induced germ cell and male gonadal toxicity in diabetic conditions. Rats were randomly divided into eight different groups - control (normal feed and water), BPA (10mg/kg/day), ZDD (fed with a Zn-deficient diet), DIA (diabetic), BPA+ZDD, BPA+DIA, ZDD+DIA and BPA+ZDD+DIA for four weeks. Animals' body and organ weight, sperm count, motility and sperm morphology were examined; testes and epididymis histopathology were investigated. Testicular DNA damage and sperm apoptosis were evaluated by halo and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays respectively. Testicular catalase and octamer-binding transcription factor 4 (OCT4) expressions were evaluated by western blot analysis. The present results demonstrated that dietary Zn-deficient condition significantly increased the BPA-induced testicular, epididymal and sperm toxicity in diabetic rats due to hypogonadism, increased sperm abnormalities, epididymis, testicular structure and DNA damages, sperm apoptosis as well as decreased testicular catalase and OCT4 expressions. The present results revealed that dietary Zn-deficient condition exacerbated the BPA-induced testicular and epididymal toxicity as well as perturbed the general male reproductive health in diabetic rats.

Zinc Deficiency Exacerbates Bisphenol A-Induced Hepatic and Renal Damage: Delineation of Molecular Mechanisms.

Zinc (Zn) plays an important role in the maintenance of redox status in the biological system. Zn deficiency has been found to be associated with negative effects on the functioning of many organ systems, including hepatic and renal systems. Bisphenol A (BPA) can alter Zn homeostasis and perturb the physiological system by provoking oxidative stress, which can lead to damage of different organs such as reproductive, immune, neuroendocrine, hepatic and renal systems. The present study aims to investigate the toxicity of BPA in Zn deficient condition in the liver and kidney of rat and to correlate its synergistic actions. Zn deficiency was induced by feeding Zn-deficient diet (ZDD), and BPA was administered orally (100mg/kg/d). Male Sprague-Dawley rats were divided into four groups: NPD + Vehicle (normal feed and water), NPD + BPA (100mg/kg/d), ZDD + Vehicle (fed with Zn-deficient diet only) and ZDD + BPA (Zn-deficient diet + BPA; 100mg/kg/d) for 8weeks. Biochemical, histopathological, TUNEL assay and protein expression profiles were determined to decipher the oxidative damage induced by ZDD and the toxicant BPA. Expression profile of nuclear factor erythroid 2-related factor 2, proliferating cell nuclear antigen, kelch-like ECH-associated protein 1, superoxide dismutase-1, metallothionein and apoptosis incidence showed that ZDD and BPA have a synergistic exacerbation effect on the liver and kidney of rat.

Expression pattern of genes encoding bZIP56, WRKY1 and NAM-B1 transcription factors under Zn deficiency conditions in bread wheat (Triticum aestivum L.)

Expression pattern of genes encoding bZIP56, WRKY1 and NAM-B1 transcription factors under Zn deficiency conditions in bread wheat (Triticum aestivum L.)

Zinc deficiency in cucumber plants can be alleviated by fullerenol

Zinc (Zn) deficiency is one of the most limiting factors in plant growth and productivity worldwide. Among carbon-based nanomaterials, water-soluble fullerene derivates offer unique opportunities to increase crop productivity and protection. In this work, we evaluated the stress mitigation effects of fullerenol in cucumber plants (Cucumis sativus L.) submitted to Zn deficiency conditions. Cucumber plants were grown hydroponically, either with (+Zn) or without (−Zn) a Zn supply, with (+F) or without (−F) a fullerenol supply. Fullerenol was added in a nutrient solution either before the beginning of Zn deficiency (plant priming) or at its start. A nutrient imbalance, leaf yellowing and spotting, a reduced electron transport rate (ETR), enhanced oxidative damage by excessive production of malondialdehyde (MDA) and retarded plant growth were found in Zn-deficient plants. After fullerenol treatment, some symptoms of Zn deficiency were alleviated. Overall, fullerenol decreased leaf MDA and spotting (visual observations). When fullerenol was added in a Zn-free solution, plants exhibited enhanced leaf chlorophyll or shoot dry biomass compared with non-treated plants. Also, an increase in xylem sap or young leaf Zn was observed in fullerenol-treated plants under Zn deficiency. With the exception of the MDA responses and spotting, these effects appear to occur in a dose-dependent manner. In contrast, the Zn-fed plants remained phenotypically unaffected by fullerenol. Thus, fullerenol probably alleviated Zn deficiency due to an improvement in Zn remobilization and the antioxidant capacity of the plants, in turn decreasing lipid peroxidation.

Effect of Soil Zinc Deficiency on Morphological Traits, Yield, and Yield Components and Activity of Zinc-Containing Enzymes in Zn-Efficient and -Inefficient Bread Wheat Cultivars

ABSTRACT To investigate the effect of soil Zn deficiency on some morphological characteristics of common wheat (Triticum aestivum L.), a factorial experiment was performed in a completely randomized design with three replications in a greenhouse. Zn-efficient and -inefficient cultivars were grown in two conditions of Zn adequacy and deficiency and some morphological traits, as well as Zn concentrations of grain, root, and leaf were recorded. Also, the activity of enzymes alcohol dehydrogenase (ADH), alkaline phosphatase (ALP), guaiacol peroxidase (GPX), and polyphenol oxidase (PPO) was evaluated in both roots and leaves at two stages, 30 days after germination (vegetative) and 30% spiking (reproductive). The results showed that in Zn deficiency conditions, the root Zn concentration of Zn-efficient cultivars was significantly (P ≤ .01) higher than those of Zn-inefficient cultivars. Also, grain Zn concentration in Hamoon (Zn-efficient) was significantly (P ≤ .01) higher than Zn-inefficient cultivars. Decreases in shoot dry yield (12.8%), Zn concentrations of root and grain (18%), and leaf chlorophyll content (54%) in Zn-inefficient cultivars were higher than Zn-efficient cultivars. The activity of ALP, ADH, and PPO was declined under Zn deficiency conditions while the activity of GPX was increased in this condition. In conclusion, the results of this study showed that Zn-efficient cultivars produce better yield than Zn-inefficient cultivars under Zn deficiency condition and are able to store much Zn in the grains. Also, under Zn deficiency conditions, the activity of Zn-containing enzymes in Zn-efficient cultivars is more than the Zn-inefficient ones.

Dietary Zinc Deficiency Increases Bisphenol A Toxicity in Diabetic Rat: Studies on the Testicular and Epididymal Pathophysiology

Bisphenol A (BPA), an endocrine disrupter extensively used in plastics products, that causes male reproductive dysfunction in humans and experimental systems. Type 1 diabetes (T1D) associates hyperglycaemia dysregulate the spermatogenesis and antioxidant status in the testes, which negatively impact on male fertility in adults. Dietary zinc (Zn) deficiency is a global health concern, because majority of the individuals are suffering from certain range of Zn‐deficiency. Zn plays an important role in the regulation and maintenance of testicular physiology and the overall reproductive health. The present study was aimed to investigate the influence of Zn‐deficiency on BPA induced germinal cell and male gonadal toxicity in diabetic rat. Sprague Dawley rats (4 weeks old) were randomly divided into eight different groups; like control (standard pellet diet and aquapure drinking water), BPA (10 mg/kg/day), Zn‐deficient diet (ZDD; Zn‐deficient diet), diabetic (DIA), BPA+ZDD, BPA+DIA, ZDD+DIA and BPA+ZDD+DIA for four weeks. Diabetes was induced by injecting single dose of streptozotocin (55 mg/kg) freshly prepared in cold citrate buffer at pH 4.5. The evaluation of various end‐points such as assessment of body and organ weights, biochemical estimations, sperm parameters. testes and epididymis histopathology, quantification of testicular DNA damage and sperm apoptosis were conducted. Testicular 8‐OHdG immunoexpression as well as catalase and OCT4 expressions were carried out by western blot analysis. The results showed that dietary Zn‐deficient condition significantly increased the BPA toxicity by decreasing body and organ weight, serum albumin and increasing glucose, SGPT, SGOT and BUN significantly in diabetic condition. Further, significant decrease in sperm count, sperm motility and increase in sperm deformities were observed. The Zn‐deficiency significantly increased the BPA induced testicular and epididymal tissue injury, elevated testicular 8‐OHdG immunoexpression and sperm apoptosis in diabetic rat. Moreover, BPA exposure significantly decreased the testicular catalase and OCT4 expressions in dietary Zn‐deficient diabetic rat. The present results concluded that dietary Zn‐deficiency exacerbated the BPA induced gonadal toxicity by hypogonadism, increased sperm abnormalities, testicular and epididymal cellular damage, testicular DNA damages, sperm apoptosis as well as decreased the testicular catalase and OCT4 expressions in diabetic rat.

Identification of Zinc Efficiency-Associated Loci (ZEALs) and Candidate Genes for Zn Deficiency Tolerance of Two Recombination Inbred Line Populations in Maize.

Zinc (Zn) deficiency is one of the most common micronutrient disorders in cereal plants, greatly impairing crop productivity and nutritional quality. Identifying the genes associated with Zn deficiency tolerance is the basis for understanding the genetic mechanism conferring tolerance. In this study, the K22×BY815 and DAN340×K22 recombination inbred line (RIL) populations, which were derived from Zn-inefficient and Zn-efficient inbred lines, were utilized to detect the quantitative trait loci (QTLs) associated with Zn deficiency tolerance and to further identify candidate genes within these loci. The BLUP (Best Linear Unbiased Prediction) values under Zn-deficient condition (-Zn) and the ratios of the BLUP values under Zn deficient condition to the BLUP values under Zn-sufficient condition (-Zn/CK) were used to perform linkage mapping. In QTL analysis, 21 QTLs and 33 QTLs controlling the Zn score, plant height, shoot and root dry weight, and root-to-shoot ratio were detected in the K22×BY815 population and the DAN340×K22 population, explaining 5.5–16.6% and 4.2–23.3% of phenotypic variation, respectively. In addition, seventeen candidate genes associated with the mechanisms underlying Zn deficiency tolerance were identified in QTL colocalizations or the single loci, including the genes involved in the uptake, transport, and redistribution of Zn (ZmIRT1, ZmHMAs, ZmNRAMP6, ZmVIT, ZmNAS3, ZmDMAS1, ZmTOM3), and the genes participating in the auxin and ethylene signal pathways (ZmAFBs, ZmIAA17, ZmETR, ZmEIN2, ZmEIN3, ZmCTR3, ZmEBF1). Our findings will broaden the understanding of the genetic structure of the tolerance to Zn deficiency in maize.

Improvement of the physiological response of barley plants to both Zinc deficiency and toxicity by the application of calcium silicate

An adequate availability of Zinc (Zn) is crucial for plant growth and development given the essentiality of this element. Thus, both Zn deficiency and Zn toxicity can limit crop yields. In plants, the responses to Zn imbalances involve important physiological aspects such as reactive oxygen species (ROS) accumulation, phytohormone balance, tricarboxylic acid cycle (TCA) metabolism, and organic acids (OAs) accumulation. However, a way to improve tolerance to stresses such as those produced by nutritional imbalances is the application of beneficial elements such as silicon (Si). In this study, we grew barley plants in hydroponics under Zn deficiency and toxicity conditions, applying Si in the form of CaSiO3 in order to assess its effectiveness against Zn imbalances. Parameters related to plant growth, oxidative stress, TCA enzyme activities, phytohormones and OAs accumulation were analyzed. Both Zn deficiency and toxicity reduced leaf biomass, increased ROS accumulation, and affected phytohormone and OAs concentrations and TCA enzyme activities. CaSiO3 treatment was effective in counteracting these effects enhancing Zn accumulation under Zn deficient conditions and limiting its accumulation under toxic conditions. In addition, this treatment decreased ROS levels, and improved ascorbate/glutathione and phytohormonal responses, citrate synthase activity, and malate/oxalate ratio. Therefore, this study enhanced the notion of the efficacy of CaSiO3 in improving tolerance to Zn imbalances.