PGPR-induced regulation of Zn and Fe transporters in wheat (Triticum aestivum L.) uncovered through integrated genome-wide analysis and functional validation.
Overall, the results show that PGPR modulate metal‑transporter gene networks and improve micronutrient biofortification in wheat, providing a genotype‑responsive and sustainable approach to address micronutrient deficiency.
Abstract
Zinc (Zn) and iron (Fe) deficiencies affect more than two billion people globally, particularly in cereal-dependent regions where wheat, despite its high consumption, provides inadequate micronutrient levels. Conventional interventions such as genetic modification and mineral supplementation remain costly, unevenly accessible, and insufficient for large-scale nutritional improvement. Agronomic biofortification using plant growth-promoting rhizobacteria (PGPR) offers a promising yet underexplored alternative, especially for regulating metal homeostasis genes in wheat. This research integrates multi-season field trials of Zn-biofortified Akbar-19 and the local cultivar Khaista-17, conducted under reduced fertilizer conditions with PGPR consortia. Afterwards, genome-wide analyses including phylogenetic relationships, promoter elements, gene interaction networks, expression profiles, and conserved domains/motifs of the TaNAS (19 genes), TaNAAT (6), TaDMAS (3), and TaVIT (31) gene families was performed. This was followed by transcriptional expression (qPCR) of six candidate genes in wheat grown under hydroponic Zn/Fe stress in the presence of PGPR. Field evaluation showed that PGPR inoculation boosted yield by 15-18% and increased grain Zn/Fe by 15-20% in Akbar-19 and 25-28% in Khaista-17, consistently outperforming fertilizer-only controls across both seasons. The genome-wide analyses exhibited the phylogenetic relationship of wheat TaDMAS, TaNAAT, and TaNAS genes with barley, while TaVIT and TaVTL genes with rice and maize. Promoter analyses of these genes showed an enrichment of stress-responsive cis-elements, such as IDE1/2, ZDRE1/2, IRO2-binding sites, and metal-responsive elements suggesting coordinated regulation of micronutrient chelation, uptake, and homeostasis. qPCR results confirmed PGPR-induced upregulation of NAS1, NAS6, NAS9, NAAT2, DMAS1, and VIT2 under Zn/Fe stress, with stronger induction in Khaista-17. Overall, the results show that PGPR modulate metal‑transporter gene networks and improve micronutrient biofortification in wheat, providing a genotype‑responsive and sustainable approach to address micronutrient deficiency.
Rice is one of the most significant crops consumed daily by individuals. Enhancing and biofortifying rice to augment its nutritional value is a promising strategy for improving public health and tackling the widespread issue of micronutrient deficiencies. This study primarily attempted to evaluate the developed Cas9-free edited lines grown hydroponically with a triple knockout of the negative metal sensor regulator uptake (OsHRZ1, OsHRZ2, and OsLCT1). This result shows that the Cas9-free edited lines’ performance was excellent, with no significant effect on the plant's agronomic performance or yield penalty due to multiplex knockout of genes, in addition to growing under cadmium stress conditions. The protein content of seeds was higher in the Cas9-free edited lines than the protein concentrations observed in the wild type (control/treated), where the protein concentration ranged from 17 to18 mg g−1 FW protein compared to the wild type (normal/treated) (7.24, 7.08) mg g−1 FW, respectively. The concentration varies based on the growth condition under deficient or sufficient Fe/Zn. Photosynthetic rates were increased in Cas9-free edited plants in comparison to wild rice plants, correlating with enhanced agronomic yield parameters and tolerance of cadmium conditions. Rice pollen grain viability and fertility were examined to check the effect of excess iron/zinc on pollen grain viability, fertility, and germination. The expression of genes closely linked to iron, zinc, and cadmium uptake and translocation in rice endosperm was studied. Developed rice lines hold a huge promise to overcome micronutrient malnutrition worldwide.
Lead (Pb) toxicity significantly undermines agricultural productivity and food safety by disrupting plant growth and vital physiological functions, highlighting the urgent need for innovative approaches to enhance nutrient uptake and utilization. In this context, the use of lysine-metal complexes emerges as a crucial strategy, not only mitigating Pb toxicity but also optimizing mineral nutrient acquisition in plants, thereby supporting essential physiological processes and improving overall plant resilience. This study investigated the efficacy of lysine-metal complexes (copper-lysine [Cu-Lys], magnesium-lysine [Mg-Lys], and calcium-lysine [Ca-Lys]) in alleviating Pb-induced stress in maize (Zea mays L.) through the enhancement of growth attributes, photosynthetic efficiency, antioxidant defense, and cellular mechanisms. A pot experiment was conducted at Zayed University, UAE, where Pb was applied at 0, 100, and 200 mg kg-1 soil using Pb(NO3)2, and foliar treatments of Lys-metal complexes (10 mg L-1) were applied weekly, starting 14 days after sowing. The results revealed that Pb stress significantly reduced plant growth, photosynthetic pigments, gas exchange, and biomass, accompanied by increased oxidative stress markers such as hydrogen peroxide and malondialdehyde. However, Lys-metal complexes, particularly copper-lysine complex (Cu-Lys), markedly improved growth, photosynthetic pigments, gas exchange parameters, and antioxidant activities, including the AsA-GSH cycle and enzymatic antioxidants (superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase). Proline accumulation and modulation of cellular fractionation were observed, leading to reduced Pb translocation and enhanced Pb immobilization in the cell wall. Among the treatments, Cu-Lys demonstrated superior effectiveness, followed by magnesium-lysine complex (Mg-Lys) and Ca-Lys. In conclusion, Lys-metal complexes mitigate Pb toxicity by improving physiological and biochemical responses, reducing Pb uptake, and enhancing antioxidant defense mechanisms. These findings highlight the potential of Cu-Lys, Mg-Lys, and Ca-Lys as sustainable strategies to enhance Z. mays resilience in Pb-contaminated environments.
Manar Fawzi Bani Mfarrej, D. Binjawhar· Journal of Environmental Qua...· 0 citations
This study identifies key candidate SbCPK genes associated with seed germination and hormonal signal transduction, providing a fundamental theoretical basis for further elucidating the calcium signaling-mediated molecular regulatory mechanisms of PHS in sorghum.
Yuwen Jiang, Manjing Chen, Jiaqi Shen et al.· Frontiers in Plant Science· 0 citations
Zinc (Zn) deficiency in soils poses a serious threat to global food and nutritional security, especially in developing countries where unsustainable farming, like imbalanced fertiliser use, nutrient mining and organic matter loss, is widespread. In India, surveys of over 242000 soil samples across 615 districts reveal widespread micronutrient deficiencies: 51.2 % for Zn, 58.6 % for sulfur (S) and 44.7 % for boron (B). Common combined deficiencies such as Zn + S (9.3 %), Zn + B (8.7 %) and Zn + iron (Fe) (5.8 %) vary spatially across agro-ecological zones. These findings highlight the urgent need for site-specific integrated nutrient management tailored to diverse soils and crops. Conventional Zn biofortification methods using ZnSO₄ or Zn-chelates have shown benefits but face limitations including high costs, poor adoption and reduced efficacy in acidic soils prevalent in eastern India. Alternatively, microbiological biofortification with Zn-solubilising bacteria (ZSB) offers a sustainable, low-cost solution. ZSB transform insoluble Zn into plant-available forms through mechanisms like chelation, organic acids and siderophore production, enhancing Zn uptake, grain quality and yield. This approach supports sustainable agriculture by improving nutrient use efficiency, reducing chemical inputs and promoting soil microbial health. In acid soils of Odisha, deploying effective ZSB strains offers a promising route to improve soil fertility and combat hidden hunger by boosting micronutrient content in crops. This review synthesises current understanding of ZSB-mediated Zn mobilisation and their application in sustainable Zn biofortification of rice-based systems, particularly in Zn-deficient regions and highlights key research priorities for translating laboratory insights into reliable field-scale outcomes.
K. M. Abinash, D. Shilpee, M. Mamata et al.· Plant Science Today· 0 citations
Simple Summary Sea Island cotton (Gossypium barbadense L.) is widely cultivated for its high-grade extra-long staple fiber and excellent disease resistance. However, its cultivation is increasingly threatened by soil heavy metal contamination (such as cadmium toxicity) and fungal diseases (such as Verticillium wilt caused by Verticillium dahliae). Zinc/iron-regulated transporter-like proteins (ZIPs) serve as essential membrane transporters that manage transition metal homeostasis and modulate stress responses in plants. In this study, we systematically identified 46 GbZIP genes across the G. barbadense genome and comprehensively evaluated their structural characteristics, evolutionary origin, cis-regulatory elements, and expression patterns. Transcriptional analysis demonstrated that several key GbZIP members dynamically respond to cadmium exposure, fungal infection, and their combined occurrence. These findings highlight crucial candidate genes for molecular breeding aimed at improving stress resilience and metal tolerance in premium cotton germplasm.
Ya-Hui Deng, Nan Zhao, Jidi Sun et al.· Biology· 0 citations
Biofortification of wheat has emerged as a sustainable strategy to combat global micronutrient deficiencies, particularly iron (Fe) and zinc (Zn) deficiency, while simultaneously improving grain protein quality. Among available approaches, mutation breeding has gained renewed attention as a non-transgenic tool capable of generating novel genetic variability for nutritional enhancement. This review is based on a comprehensive analysis of peer-reviewed literature retrieved from major scientific databases, including Web of Science, Scopus, PubMed, and Google Scholar. Studies published between 2005 and 2025 were critically evaluated to compare the effectiveness, advantages, limitations, and future prospects of wheat biofortification approaches. This review critically evaluates the role of mutation breeding in wheat biofortification and compares its effectiveness with conventional breeding, agronomic biofortification, and genome editing technologies. Evidence from published studies indicates that gamma-induced mutant lines have achieved significant increases in grain Fe and Zn concentrations, as well as improvements in storage protein composition, without regulatory constraints associated with transgenic methods. However, variability in genetic stability, potential yield penalties, and genotype × environment interactions remain important limitations. Overall, integrating mutation breeding with advanced molecular tools and agronomic practices offers a promising strategy for developing nutrient-enriched wheat varieties and enhancing global food and nutritional security.
G. Doktyrbay, S. Atabayeva, S. Asrandina et al.· Plants· 0 citations
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