Nanoparticle-mediated gene transformation strategies for plant genetic engineering

Can the molecular and transgenic breeding of crops be an alternative and sustainable technology to meet food demand?

The gradual increase in the worldwide population represents various challenges, and one of the most alarming being the food demand. Historically technological advances led to the development of crops that meets the requirements and demands. Currently, molecular breeding unlocks the genetic potential of crops for their improvement, positioning it as a key technology for the development of new crops. The implementation of OMICs sciences, such spatial and single cell transcriptomics is providing a large and precise information, which can be exploited for crop improvement related to increasing yield, improving the nutritional value; designing new strategies for diseases resistance and management and for conserving biodiversity. Furthermore, the use of new technologies such CRISPR/CAS9 brought us the ability to modify the selected regions of the genome to select the superior's genotypes at a short time and the use of artificial intelligence aid in the analysis of big data generated by OMICS sciences. On the other hand, the application of molecular improvement technologies open up discussion on global regulatory measures, the socio-economic and socio-ethics, as the frameworks on its global regulation and its impact on the society create the public perception on its acceptance. In this review, the use and impact of OMICs sciences and genetic engineering in crops development, the regulatory measures, the socio-economic impact and as well as the mediatic information on genetically modified crops worldwide is discussed along with comprehensive insights on the potential of molecular plant breeding as an alternative and sustainable technology to meet global food demand.

Advances in RNAi-based nanoformulations: revolutionizing crop protection and stress tolerance in agriculture

Nucleic acid-based therapeutics have the ability to tackle a wide range of diseases and stress tolerance that present significant obstacles for conventional approaches in agriculture. RNA-based medicines have become a promising approach, using nanoformulation treatments to specifically target certain diseases. Nanoformulations offer numerous benefits in comparison to alternative treatment methods, such as precise administration, minimal toxicity, and medication loading compatibility due to their bioactivity. There are a variety of nanoformulations available today, such as liposomes, polymeric nanoparticles (NPs), magnetic NPs, nanogels, and solid lipid nanoparticles (SLNs). RNA-based therapy employs intracellular gene nanoparticles containing messenger RNA (mRNA), which play an important role in stress management and pest as well as disease control. The adoption of mRNA-based technology paves the way for future technological progress. This review focuses on elucidating the process underlying the development of RNA interference (RNAi) and the diverse array of nanocarriers employed for the transportation of RNAi. Currently, this technique is being employed in the field of crop protection to combat diseases, pests, and environmental stress. The article highlights the benefits of RNAi mediated nanoformulations and discusses the significant obstacles that must be overcome to improve the viability of this technology for future applications.

Nanodelivery of nucleic acids for plant genetic engineering

Genetic engineering in plants serves as a crucial method for enhancing crop quality, yield, and climate resilience through the manipulation of genetic circuits. A novel genetic transformation approach utilizing nanocarriers as a sound plant genetic engineering technique enables the delivery of DNAs or RNAs into the plant cells. Significant advances have recently been made on the nanotechnology-based delivery of nucleic acids in plants. In this review, several nanoparticle-mediated DNA and RNA delivery systems are discussed respectively, involving latest progresses and drawbacks of these approaches used in plant genetic engineering. We also underscores the current challenges that must be addressed in the implementation of nanoparticles-based strategies for plant gene delivery. Furthermore and more importantly, plant-derived exosome-like nanoparticles that facilitate nucleic acids transfer between organisms was initially proposed as a novel and promising nanodelivery platform for the CRISPR/Cas9 genome editing toolkit in plants. We believe that this review will be beneficial for an effective exploration of nucleic acid nanodelivery to aid the plant genetic engineering in modern agriculture.

Barley2035: A decadal vision for barley research and breeding

Barley (Hordeum vulgare ssp. vulgare) is one of the oldest founder crops in human civilization and has been widely dispersed across the globe to support human society as a livestock feed and a raw material for the brewing industries. Since the early half of the 20th century, it has been used for innovative research on cytogenetics, biochemistry, and genetics, facilitated by its mode of reproduction through self-pollination and its true diploid status, which have contributed to the accumulation of numerous germplasm and mutant resources. In the era of molecular genomics and biology, a multitude of barley genes and their related regulatory mechanisms have been identified and functionally validated, providing a paradigm for equivalent studies in other Triticeae crops. This review highlights important advances on barley research over the past decade, focusing mainly on genomics and genomics-assisted germplasm exploration, genetic dissection of developmental and adaptation-related traits, and the complex dynamics of yield and quality formation. In the coming decade, the prospect of integrating these innovations in barley research and breeding shows great promise. Barley is proposed as a reference Triticeae crop for the discovery and functional validation of new genes and the dissection of their molecular mechanisms. The application of precise genome editing as well as genomic prediction and selection, further enhanced by artificial intelligence-based tools and applications, is expected to promote barley improvement to efficiently meet the evolving global demands for this important crop.

The role of nanoparticles in transforming plant genetic engineering: advancements, challenges and future prospects

Despite years of progress in biotechnology, altering the genetic makeup of many plant species, especially their plastids, remains challenging. The existence of a cell wall poses a significant obstacle to the effectual transportation of biomolecules. Developing efficient methods to introduce genes into plant cells and organelles without causing harm is an ongoing area of research. Traditional approaches like Agrobacterium-mediated transformation, biolistic particle delivery, electroporation and polyethylene glycol (PEG) transformation have shown some success but come with limitations like laborious, time-consuming and causing tissue damage. For instance, the Agrobacterium method can be applied only to the restricted host range, while PEG transformation and biolistic particle delivery are not very efficient. In contrast, nanotechnology made an appearance in the field of genetic engineering. Nanoparticles act as delivery vehicles for many cargos in animals. However, in plants, the application of nanocarriers for the delivery of biomolecules is still in its infant stage. Nonetheless, it holds immense potential for the future of plant biotechnology and genome editing.

Form and Function: The Factors That Influence the Efficacy of Nanomaterials for Gene Transfer to Plants

Nanoparticle (NP)-mediated gene delivery offers a promising alternative to traditional methods in plant biotechnology, facilitating genetic transformations with enhanced precision and efficiency. This review discusses key factors influencing NP efficacy, including plant cell wall composition, DNA/NP ratios, exposure time, cargo loading, and post-transformation assessments. We explore the challenges of NP cytotoxicity, transformation efficiency, and regeneration while addressing environmental impacts and regulatory considerations. We emphasize the potential for stimulus-responsive NPs and scalable delivery methods to optimize gene editing in agriculture.

Nanomaterials-plants-microbes interaction: plant growth promotion and stress mitigation

Soil salinization, extreme climate conditions, and phytopathogens are abiotic and biotic stressors that remarkably reduce agricultural productivity. Recently, nanomaterials have gained attention as effective agents for agricultural applications to mitigate such stresses. This review aims to critically appraise the available literature on interactions involving nanomaterials, plants, and microorganisms. This review explores the role of nanomaterials in enhancing plant growth and mitigating biotic and abiotic stresses. These materials can be synthesized by microbes, plants, and algae, and they can be applied as fertilizers and stress amelioration agents. Nanomaterials facilitate nutrient uptake, improve water retention, and enhance the efficiency of active ingredient delivery. Nanomaterials strengthen plant antioxidant systems, regulate photosynthesis, and stabilize hormonal pathways. Concurrently, their antimicrobial and protective properties provide resilience against biotic stressors, including pathogens and pests, by promoting plant immune responses and optimizing microbial-plant symbiosis. The synergistic interactions of nanomaterials with beneficial microorganisms optimize plant growth under stress conditions. These materials also serve as carriers of nutrients, growth regulators, and pesticides, thus acting like "smart fertilizers. While nanotechnology offers great promise, addressing potential environmental and ecotoxicological risks associated with their use is necessary. This review outlines pathways for leveraging nanotechnology to achieve resilient, sustainable, and climate-smart agricultural systems by integrating molecular insights and practical applications.

De novo root regeneration from leaf explant: a mechanistic review of key factors behind cell fate transition

MAIN CONCLUSION

De novo root regeneration (DNRR) involves activation of special cells after wounding, along with the converter cells, reactive oxygen species, ethylene, and jasmonic acid, also playing key roles. An updated DNRR model is presented here with gene regulatory networks. Root formation after tissue injury is a type of plant regeneration known as de novo root regeneration (DNRR). DNRR system has wide applications in agriculture and tissue culture biotechnology. This review summarizes the recent advancements in the DNRR model for the cellular and molecular framework, targeting leaf explant of Arabidopsis and highlighting differences among direct and indirect pathways. Key findings highlight the presence of special cells in leaf explants after wounding, under different time lapses, through single-cell sequencing of the transcriptional landscape. The possible roles of reactive oxygen species (ROS), ethylene, and jasmonic acid are explored in the early establishment of wounding signals (short/long) for auxin biosynthesis, ultimately leading to adventitious root formation. The synergistic manner of 3rd type of special cells along converter and regeneration-competent cells automatically leads towards cell fate transition for auxin flux in regeneration-competent cells. The signaling mechanisms of these suggested special cells need to be further investigated to understand the DNRR mechanistic story entirely, in addition to root-to-root regeneration and stem-to-root regeneration. Meta-analysis of DNRR is also presented for past and future reference.

Carbon-based nanocarriers for plant growth promotion: fuelling when needed

Climate change (i.e., rising temperature and precipitation) due to global warming is affecting soil fertility, thereby significantly causing a decrease in agriculture production worldwide. At the same time, increasing demands for food supplies with the growing global population puts extra pressure to improve agricultural production. Indeed, chemical fertilizers and pesticides are a great help in fuelling agro-production, but their excess use could deteriorate the environment and human health. Nevertheless, nanomaterials, especially carbon-based nanostructured materials (CB-NMs), have revolutionized the agricultural sector in various ways including the on-demand supply of essential nutrients, biomolecules, and growth factors to plants. Carbon nanofibers (CNFs) are one such example that can be tuned to carry essential nutrients (i.e., Fe, Cu, Zn, and Mo) and deliver to plants when and what is in need. As a result, it not only improves the crop yield but also maintains the nutritional quality (protein, carbohydrate, and mineral contents) of plant products. This review discusses the most innovative development in CB-NM-based carriers (CNFs, carbon nanotubes (CNTs), and graphene as well as its derivatives) for plant growth applications including the approaches being used for their lab-scale synthesis. In addition, their application as the carrier of micronutrients and biomolecules and the successful delivery (and the underlying mechanism) of genes, nucleic acids, microbes, and their components in plants are discussed.

Development of high-throughput tissue culture-free plant transformation systems

Efficient transformation systems are highly desirable for plant genetic research and biotechnology product development efforts. Tissue culture-free transformation (TCFT) and minimal tissue culture transformation (MTCT) systems have great potential in addressing genotype-dependency challenge, shortening transformation timeline, and improving operational efficiency by greatly reducing personnel and supply costs. The development of Arabidopsis floral dip transformation method almost 3 decades ago has greatly expedited plant genomic research. However, development of efficient TCFT or MTCT systems in non-Brassica species had limited success until recently despite the demonstration of successful in planta transformation in many plant species. In the last few years, there have been some major advances in the development of such systems in several crops using novel approaches. This article will review these new advances and discuss potential areas for further development.

Nano-assisted delivery tools for plant genetic engineering: a review on recent developments

Conventional approaches like Agrobacterium-mediated transformation, viral transduction, biolistic particle bombardment, and polyethylene glycol (PEG)-facilitated delivery methods have been optimized for transporting specific genes to various plant cells. These conventional approaches in genetically modified crops are dependent on several factors like plant types, cell types, and genotype requirements, as well as numerous disadvantages such as time-consuming, untargeted distribution of genes, and high cost of cultivation. Therefore, it is suggested to develop novel techniques for the transportation of genes in crop plants using tailored nanoparticles (NPs) of manipulative and controlled high-performance features synthesized using green and chemical routes. It is observed that site-specific delivery of genes exhibits high efficacy in species-independent circumstances which leads to an increased level of productivity. Therefore, to achieve these outcomes, NPs can be utilized as gene nano-carriers for excellent delivery inside crops (i.e., cotton, tobacco, rice, wheat, okra, and maize) for desired genetic engineering modifications. As outcomes, this review provides an outline of the conventional techniques and current application of numerous nano-enabled gene delivery needed for crop gene manipulation, the benefits, and drawbacks associated with state-of-the-art techniques, which serve as a roadmap for the possible applicability of nanomaterials in plant genomic engineering as well as crop improvement in the future.

Improving transformation and regeneration efficiency in medicinal plants: insights from other recalcitrant species

Medicinal plants are integral to traditional medicine systems worldwide, being pivotal for human health. Harvesting plant material from natural environments, however, has led to species scarcity, prompting action to develop cultivation solutions that also aid conservation efforts. Biotechnological tools, specifically plant tissue culture and genetic transformation, offer solutions for sustainable, large-scale production and enhanced yield of valuable biomolecules. While these techniques are instrumental to the development of the medicinal plant industry, the challenge of inherent regeneration recalcitrance in some species to in vitro cultivation hampers these efforts. This review examines the strategies for overcoming recalcitrance in medicinal plants using a holistic approach, emphasizing the meticulous choice of explants (e.g. embryonic/meristematic tissues), plant growth regulators (e.g. synthetic cytokinins), and use of novel regeneration-enabling methods to deliver morphogenic genes (e.g. GRF/GIF chimeras and nanoparticles), which have been shown to contribute to overcoming recalcitrance barriers in agriculture crops. Furthermore, it highlights the benefit of cost-effective genomic technologies that enable precise genome editing and the value of integrating data-driven models to address genotype-specific challenges in medicinal plant research. These advances mark a progressive step towards a future where medicinal plant cultivation is not only more efficient and predictable but also inherently sustainable, ensuring the continued availability and exploitation of these important plants for current and future generations.

Nanotechnology for Healthcare: Plant-Derived Nanoparticles in Disease Treatment and Regenerative Medicine

Nanotechnology has revolutionised biomedical research, offering innovative healthcare solutions. Plant-based nanotechnology is emerging as a sustainable alternative, minimising environmental impacts and enhancing therapeutic effectiveness. This paper explores the potential of plant-derived nanoparticles (PNPs) in medicine, highlighting their biocompatibility, multifunctionality, and eco-friendliness. PNPs, synthesised through green methods, have demonstrated promising applications in drug delivery, cancer therapy, antimicrobial treatments, and tissue regeneration. Their unique properties, such as a high surface area and bioactive components, enable improved drug delivery, targeting, and controlled release, reducing side effects and enhancing treatment efficacy. Additionally, plant-derived compounds' inherent antimicrobial and antioxidant properties, retained within platinum nanoparticles (PNPs), present innovative opportunities for combating antimicrobial resistance and promoting wound healing. Despite their potential, challenges remain in standardising PNP synthesis, ensuring consistency, and scaling up production for industrial applications. This review emphasises the need for further research on PNP toxicity, biocompatibility, and regulatory frameworks to fully harness their capabilities in clinical and commercial applications. Plant-based nanotechnology represents a promising, greener alternative for advancing healthcare solutions, aligning with global sustainability goals.

Biodegradable silica nanoparticles for efficient linear DNA gene delivery

Targeting, safety, scalability, and storage stability of vectors are still challenges in the field of nucleic acid delivery for gene therapy. Silica-based nanoparticles have been widely studied as gene carriers, exhibiting key features such as biocompatibility, simplistic synthesis, and enabling easy surface modifications for targeting. However, the ability of the formulation to incorporate DNA is limited, which restricts the number of DNA molecules that can be incorporated into the particle, thereby reducing gene expression. Here we use polymerase chain reaction (PCR)-generated linear DNA molecules to augment the coding sequences of gene-carrying nanoparticles, thereby maximizing nucleic acid loading and minimizing the size of these nanocarriers. This approach results in a remarkable 16-fold increase in protein expression six days post-transfection in cells transfected with particles carrying the linear DNA compared with particles bearing circular plasmid DNA. The study also showed that the use of linear DNA entrapped in DNA@SiO2 resulted in a much more efficient level of gene expression compared to standard transfection reagents. The system developed in this study features simplicity, scalability, and increased transfection efficiency and gene expression over existing approaches, enabled by improved embedment capabilities for linear DNA, compared to conventional methods such as lipids or polymers, which generally show greater transfection efficiency with plasmid DNA. Therefore, this novel methodology can find applications not only in gene therapy but also in research settings for high-throughput gene expression screenings.

Adaptation of High-Altitude Plants to Harsh Environments: Application of Phenotypic-Variation-Related Methods and Multi-Omics Techniques

High-altitude plants face extreme environments such as low temperature, low oxygen, low nutrient levels, and strong ultraviolet radiation, causing them to adopt complex adaptation mechanisms. Phenotypic variation is the core manifestation of ecological adaptation and evolution. Many plants have developed a series of adaptive strategies through long-term natural selection and evolution, enabling them to survive and reproduce under such harsh conditions. This article reviews the techniques and methods used in recent years to study the adaptive evolution of high-altitude plants, including transplantation techniques, genomics, transcriptomics, proteomics, and metabolomics techniques, and their applications in high-altitude plant adaptive evolution. Transplantation technology focuses on phenotypic variation, which refers to natural variations in morphological, physiological, and biochemical characteristics, exploring their key roles in nutrient utilization, photosynthesis optimization, and stress-resistance protection. Multiple omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, have revealed genes, regulatory pathways, and metabolic networks associated with phenotypic variations at the genetic and molecular levels. At the same time, the limitations and deficiencies of current technologies used to study plant adaptation to high-altitude environments were discussed. In addition, we propose future improvements to existing technologies and advocate for the integration of different technologies at multiple levels to study the molecular mechanisms of plant adaptation to high-altitude environments, thus providing insights for future research in this field.

Can nanotechnology and genomics innovations trigger agricultural revolution and sustainable development?

At the dawn of new millennium, policy makers and researchers focused on sustainable agricultural growth, aiming for food security and enhanced food quality. Several emerging scientific innovations hold the promise to meet the future challenges. Nanotechnology presents a promising avenue to tackle the diverse challenges in agriculture. By leveraging nanomaterials, including nano fertilizers, pesticides, and sensors, it provides targeted delivery methods, enhancing efficacy in both crop production and protection. This integration of nanotechnology with agriculture introduces innovations like disease diagnostics, improved nutrient uptake in plants, and advanced delivery systems for agrochemicals. These precision-based approaches not only optimize resource utilization but also reduce environmental impact, aligning well with sustainability objectives. Concurrently, genetic innovations, including genome editing and advanced breeding techniques, enable the development of crops with improved yield, resilience, and nutritional content. The emergence of precision gene-editing technologies, exemplified by CRISPR/Cas9, can transform the realm of genetic modification and enabled precise manipulation of plant genomes while avoiding the incorporation of external DNAs. Integration of nanotechnology and genetic innovations in agriculture presents a transformative approach. Leveraging nanoparticles for targeted genetic modifications, nanosensors for early plant health monitoring, and precision nanomaterials for controlled delivery of inputs offers a sustainable pathway towards enhanced crop productivity, resource efficiency, and food safety throughout the agricultural lifecycle. This comprehensive review outlines the pivotal role of nanotechnology in precision agriculture, emphasizing soil health improvement, stress resilience against biotic and abiotic factors, environmental sustainability, and genetic engineering.

Advancements in plant transformation: from traditional methods to cutting-edge techniques and emerging model species

The ability to efficiently genetically modify plant species is crucial, driving the need for innovative technologies in plant biotechnology. Existing plant genetic transformation systems include Agrobacterium-mediated transformation, biolistics, protoplast-based methods, and nanoparticle techniques. Despite these diverse methods, many species exhibit resistance to transformation, limiting the applicability of most published methods to specific species or genotypes. Tissue culture remains a significant barrier for most species, although other barriers exist. These include the infection and regeneration stages in Agrobacterium, cell death and genomic instability in biolistics, the creation and regeneration of protoplasts for protoplast-based methods, and the difficulty of achieving stable transformation with nanoparticles. To develop species-independent transformation methods, it is essential to address these transformation bottlenecks. This review examines recent advancements in plant biotechnology, highlighting both new and existing techniques that have improved the success rates of plant transformations. Additionally, several newly emerged plant model systems that have benefited from these technological advancements are also discussed.

Efficient Regeneration of Transgenic Rice from Embryogenic Callus via Agrobacterium-Mediated Transformation: A Case Study Using GFP and Apple MdFT1 Genes

Genetic transformation is a critical tool for gene manipulation and functional analyses in plants, enabling the exploration of key phenotypes and agronomic traits at the genetic level. While dicotyledonous plants offer various tissues for in vitro culture and transformation, monocotyledonous plants, such as rice, have limited options. This study presents an efficient method for genetically transforming rice (Oryza sativa L.) using seed-derived embryogenic calli as explants. Two target genes were utilized to assess regeneration efficiency: green fluorescent protein (eGFP) and the apple FLOWERING LOCUS T (FT)-like gene (MdFT1). Antisense MdFT1 was cloned into a vector controlled by the rice α-amylase 3D (Ramy3D) promoter, while eGFP was fused to Cas9 under the Ubi promoter. These vectors were introduced separately into rice embryogenic calli from two Korean cultivars using Agrobacterium-mediated transformation. Transgenic seedlings were successfully regenerated via hygromycin selection using an in vitro cultivation system. PCR confirmed stable transgene integration in the transgenic calli and their progeny. Fluorescence microscopy revealed eGFP expression, and antisense MdFT1-expressing lines exhibited notable phenotypic changes, including variations in plant height and grain quality. High transformation efficiency and regeneration frequency were achieved for both tested cultivars. This study demonstrated the effective use of seed-derived embryogenic calli for rice transformation, offering a promising approach for developing transgenic plants in monocot species.

Plant regeneration in the new era: from molecular mechanisms to biotechnology applications

Plants or tissues can be regenerated through various pathways. Like animal regeneration, cell totipotency and pluripotency are the molecular basis of plant regeneration. Detailed systematic studies on Arabidopsis thaliana gradually unravel the fundamental mechanisms and principles underlying plant regeneration. Specifically, plant hormones, cell division, epigenetic remodeling, and transcription factors play crucial roles in reprogramming somatic cells and reestablishing meristematic cells. Recent research on basal non-vascular plants and monocot crops has revealed that plant regeneration differs among species, with various plant species using distinct mechanisms and displaying significant differences in regenerative capacity. Conducting multi-omics studies at the single-cell level, tracking plant regeneration processes in real-time, and deciphering the natural variation in regenerative capacity will ultimately help understand the essence of plant regeneration, improve crop regeneration efficiency, and contribute to future crop design.

Exploiting viral vectors to deliver genome editing reagents in plants

Genome editing holds great promise for the molecular breeding of plants, yet its application is hindered by the shortage of simple and effective means of delivering genome editing reagents into plants. Conventional plant transformation-based methods for delivery of genome editing reagents into plants often involve prolonged tissue culture, a labor-intensive and technically challenging process for many elite crop cultivars. In this review, we describe various virus-based methods that have been employed to deliver genome editing reagents, including components of the CRISPR/Cas machinery and donor DNA for precision editing in plants. We update the progress in these methods with recent successful examples of genome editing achieved through virus-based delivery in different plant species, highlight the advantages and limitations of these delivery approaches, and discuss the remaining challenges.

Advances in and Perspectives on Transgenic Technology and CRISPR-Cas9 Gene Editing in Broccoli

Broccoli, a popular international Brassica oleracea crop, is an important export vegetable in China. Broccoli is not only rich in protein, vitamins, and minerals but also has anticancer and antiviral activities. Recently, an Agrobacterium-mediated transformation system has been established and optimized in broccoli, and transgenic transformation and CRISPR-Cas9 gene editing techniques have been applied to improve broccoli quality, postharvest shelf life, glucoraphanin accumulation, and disease and stress resistance, among other factors. The construction and application of genetic transformation technology systems have led to rapid development in broccoli worldwide, which is also good for functional gene identification of some potential traits in broccoli. This review comprehensively summarizes the progress in transgenic technology and CRISPR-Cas9 gene editing for broccoli over the past four decades. Moreover, it explores the potential for future integration of digital and smart technologies into genetic transformation processes, thus demonstrating the promise of even more sophisticated and targeted crop improvements. As the field continues to evolve, these innovations are expected to play a pivotal role in the sustainable production of broccoli and the enhancement of its nutritional and health benefits.

Exploring the nano-wonders: unveiling the role of Nanoparticles in enhancing salinity and drought tolerance in plants

Plants experience diverse abiotic stresses, encompassing low or high temperature, drought, water logging and salinity. The challenge of maintaining worldwide crop cultivation and food sustenance becomes particularly serious due to drought and salinity stress. Sustainable agriculture has significant promise with the use of nano-biotechnology. Nanoparticles (NPs) have evolved into remarkable assets to improve agricultural productivity under the robust climate alteration and increasing drought and salinity stress severity. Drought and salinity stress adversely impact plant development, and physiological and metabolic pathways, leading to disturbances in cell membranes, antioxidant activities, photosynthetic system, and nutrient uptake. NPs protect the membrane and photosynthetic apparatus, enhance photosynthetic efficiency, optimize hormone and phenolic levels, boost nutrient intake and antioxidant activities, and regulate gene expression, thereby strengthening plant's resilience to drought and salinity stress. In this paper, we explored the classification of NPs and their biological effects, nanoparticle absorption, plant toxicity, the relationship between NPs and genetic engineering, their molecular pathways, impact of NPs in salinity and drought stress tolerance because the effects of NPs vary with size, shape, structure, and concentration. We emphasized several areas of research that need to be addressed in future investigations. This comprehensive review will be a valuable resource for upcoming researchers who wish to embrace nanotechnology as an environmentally friendly approach for enhancing drought and salinity tolerance.

Transport of Nanoparticles into Plants and Their Detection Methods

Nanoparticle transport into plants is an evolving field of research with diverse applications in agriculture and biotechnology. This article provides an overview of the challenges and prospects associated with the transport of nanoparticles in plants, focusing on delivery methods and the detection of nanoparticles within plant tissues. Passive and assisted delivery methods, including the use of roots and leaves as introduction sites, are discussed, along with their respective advantages and limitations. The barriers encountered in nanoparticle delivery to plants are highlighted, emphasizing the need for innovative approaches (e.g., the stem as a new recognition site) to optimize transport efficiency. In recent years, research efforts have intensified, leading to an evendeeper understanding of the intricate mechanisms governing the interaction of nanomaterials with plant tissues and cells. Investigations into the uptake pathways and translocation mechanisms within plants have revealed nuanced responses to different types of nanoparticles. Additionally, this article delves into the importance of detection methods for studying nanoparticle localization and quantification within plant tissues. Various techniques are presented as valuable tools for comprehensively understanding nanoparticle-plant interactions. The reliance on multiple detection methods for data validation is emphasized to enhance the reliability of the research findings. The future outlooks of this field are explored, including the potential use of alternative introduction sites, such as stems, and the continued development of nanoparticle formulations that improve adhesion and penetration. By addressing these challenges and fostering multidisciplinary research, the field of nanoparticle transport in plants is poised to make significant contributions to sustainable agriculture and environmental management.

Nanotechnology and CRISPR/Cas9 system for sustainable agriculture

The clustered regularly interspaced short palindromic repeats (CRISPR-Cas9), a genome editing tool, has gained a tremendous position due to its therapeutic efficacy, ability to counteract abiotic/biotic stresses in plants, environmental remediation and sustainable agriculture with the aim of food security. This is mainly due to their potential of precised genome modification and numerous genetic engineering protocols with versatility as well as simplicity. This technique is quite useful for crop refinement and overcoming the agricultural losses and regaining the soil fertility hampered by hazardous chemicals. Since CRISPR/Cas9 has been widely accepted in genome editing in plants, however, their revolutionised nature and progress enable genetic engineers to face numerous challenges in plant biotechnology. Therefore, nanoparticles have addressed these challenges and improved cargo delivery and genomic editing processes. Henceforth, this barrier prevents CRISPR-based genetic engineering in plants in order to show efficacy in full potential and eliminate all the barriers. This advancement accelerates the genome editing process and its applications in plant biotechnology enable us to sustain and feed the massive population under varying environments. Genome editing tools using CRISPR/Cas9 and nanotechnology are advantageous that produce transgenic-free plants that overcome global food demands. Here, in this review, we have aimed towards the mechanisms/delivery systems linked with CRISPR/Cas9 system. We have elaborated on the applications of CRISPR/Cas9 and nanotechnology-based systems for sustainable agriculture. Moreover, the challenges and limitations associated with genome editing and delivery systems have also been discussed with a special emphasis on crop improvement.

Isolation, Purification, and Application of Protoplasts and Transient Expression Systems in Plants

Protoplasts, derived from plant cells, exhibit remarkable totipotency and hold significant value across a wide spectrum of biological and biotechnological applications. These versatile applications encompass protein subcellular localization and interaction analysis, gene expression regulation, functional characterization, gene editing techniques, and single-cell sequencing. Protoplasts' usability stems from their inherent accessibility and their ability to efficiently incorporate exogenous genes. In this review, we provide a comprehensive overview, including details on isolation procedures and influencing factors, purification and viability assessment methodologies, and the utilization of the protoplast transient expression system. The aim is to provide a comprehensive overview of current applications and offer valuable insights into protoplast isolation and the establishment of transient expression systems in a diverse range of plant species, thereby serving as a valuable resource for the plant science community.

Guidelines for Performing CRISPR/Cas9 Genome Editing for Gene Validation and Trait Improvement in Crops

With the rapid advances in plant genome editing techniques over the past 10 years, more efficient and powerful crop genome editing applications are now possible. Candidate genes for key traits can be validated using CRISPR/Cas9-based knockouts and through the up- and down-regulation of gene expression. Likewise, new trait improvement approaches can take advantage of targeted editing to improve stress tolerance, disease resistance, and nutritional traits. However, several key steps in the process can prove tricky for researchers who might be new to plant genome editing. Here, we present step-by-step guidelines and best practices for a crop genome editing pipeline that should help to improve the rate of success. Important factors in the process include proper target sequence analysis and single guide RNA (sgRNA) design, sequencing of the target site in the genotypes of interest, performing an in vitro CRISPR/Cas9 ribonucleoprotein (RNP) assay to validate the designed sgRNAs, preparing the transformation constructs, considering a protoplast editing step as further validation, and, finally, stable plant transformation and mutation detection by Sanger and/or next-generation sequencing. With these detailed guidelines, a new user should be able to quickly set up a genome editing pipeline in their crop of interest and start making progress with the different CRISPR/Cas-based editing variants for gene validation and trait improvement purposes.

Application of Nanotechnology in Plant Genetic Engineering

The ever-increasing food requirement with globally growing population demands advanced agricultural practices to improve grain yield, to gain crop resilience under unpredictable extreme weather, and to reduce production loss caused by insects and pathogens. To fulfill such requests, genome engineering technology has been applied to various plant species. To date, several generations of genome engineering methods have been developed. Among these methods, the new mainstream technology is clustered regularly interspaced short palindromic repeats (CRISPR) with nucleases. One of the most important processes in genome engineering is to deliver gene cassettes into plant cells. Conventionally used systems have several shortcomings, such as being labor- and time-consuming procedures, potential tissue damage, and low transformation efficiency. Taking advantage of nanotechnology, the nanoparticle-mediated gene delivery method presents technical superiority over conventional approaches due to its high efficiency and adaptability in different plant species. In this review, we summarize the evolution of plant biomolecular delivery methods and discussed their characteristics as well as limitations. We focused on the cutting-edge nanotechnology-based delivery system, and reviewed different types of nanoparticles, preparation of nanomaterials, mechanism of nanoparticle transport, and advanced application in plant genome engineering. On the basis of established methods, we concluded that the combination of genome editing, nanoparticle-mediated gene transformation and de novo regeneration technologies can accelerate crop improvement efficiently in the future.

Impact of magnetic field on the translocation of iron oxide nanoparticles (Fe3O4) in barley seedlings (Hordeum vulgare L.)

The effect and contribution of an external magnetic field (MF) on the uptake and translocation of nanoparticles (NPs) in plants have been investigated in this study. Barley was treated with iron oxide NPs (Fe3O4, 500 mg/L, 50-100 nm) and grown under various MF strengths (20, 42, 125, and 250 mT). The root-to-shoot translocation of NPs was assessed using a vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrometry (ICP-OES). Additionally, plant phenological parameters, such as germination, protein and chlorophyll content, and photosynthetic and nutritional status, were examined. The results demonstrated that the external MF significantly enhances the uptake of NPs through the roots. The uptake was higher at lower MF strengths (20 and 42 mT) than at higher MF strengths (125 and 250 mT). The root and shoot iron (Fe) contents were approximately 2.5-3-fold higher in the 250 mT application compared to the control. Furthermore, the MF treatments significantly increased micro-elements such as Mn, Zn, Cu, Mo, and B (P < 0.005). This effect could be attributed to the disruption of cell membranes at the root tip cells caused by both the MF and NPs. Moreover, the MF treatments improved germination rates by 28%, total protein content, and photosynthetic parameters. These findings show that magnetic field application helps the effective transport of magnetic NPs, which could be essential for NPs-mediated drug delivery, plant nutrition, and genetic transformation applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03727-4.

Technological Development and Application of Plant Genetic Transformation

Genetic transformation is an important strategy for enhancing plant biomass or resistance in response to adverse environments and population growth by imparting desirable genetic characteristics. Research on plant genetic transformation technology can promote the functional analysis of plant genes, the utilization of excellent traits, and precise breeding. Various technologies of genetic transformation have been continuously discovered and developed for convenient manipulation and high efficiency, mainly involving the delivery of exogenous genes and regeneration of transformed plants. Here, currently developed genetic transformation technologies were expounded and compared. Agrobacterium-mediated gene delivery methods are commonly used as direct genetic transformation, as well as external force-mediated ways such as particle bombardment, electroporation, silicon carbide whiskers, and pollen tubes as indirect ones. The regeneration of transformed plants usually involves the de novo organogenesis or somatic embryogenesis pathway of the explants. Ectopic expression of morphogenetic transcription factors (Bbm, Wus2, and GRF-GIF) can significantly improve plant regeneration efficiency and enable the transformation of some hard-to-transform plant genotypes. Meanwhile, some limitations in these gene transfer methods were compared including genotype dependence, low transformation efficiency, and plant tissue damage, and recently developed flexible approaches for plant genotype transformation are discussed regarding how gene delivery and regeneration strategies can be optimized to overcome species and genotype dependence. This review summarizes the principles of various techniques for plant genetic transformation and discusses their application scope and limiting factors, which can provide a reference for plant transgenic breeding.

Organelle-targeted gene delivery in plants by nanomaterials

Genetic engineering of plants has revolutionized agriculture and has had a significant impact on our everyday life. It has allowed for the production of crops with longer shelf lives, enhanced yields and resistance to pests and disease. The application of nanomaterials in plant genetic engineering has further augmented these programs with higher delivery efficiencies, biocompatibility and the potential for plant regeneration. In particular, subcellular targeting using nanomaterials has recently become possible with the cutting-edge developments within nanomaterials, but remains challenging despite the promise in organellar engineering for the introduction of useful traits and the elucidation of subcellular interactions. This feature article provides an overview of nanomaterial delivery within plants and highlights the application of recent progress in nanomaterials for subcellular organelle-targeted delivery.

A highly efficient genetic transformation system for broccoli and subcellular localization

INTRODUCTION

Agrobacterium-mediated genetic transformation has been widely used for the identification of functional genes and regulatory and developmental mechanisms in plants. However, there are still some problems of low genetic transformation efficiency and high genotype dependence in cruciferous crops.

METHODS

In this study, broccoli, a worldwide Brassica crop, was used to investigate the effects of genotype, explant type, concentration of hygromycin B used during seedling selection, overexpression vector type, RNAi and CRISPR/cas9 on the genetic transformation efficiency. At the same time, two vectors, PHG-031350 and PHG-CRa, were used for subcellular localization of the glucoraphanin synthesis-related gene FMOGS-OX5 and clubroot resistance gene by a PEG-Ca2+-mediated transient transformation system for broccoli protoplasts. Finally, the Agrobacterium-mediated genetic transformation system of broccoli was optimized and improved.

RESULTS AND DISCUSSION

This study showed that hypocotyl explants are more suitable for Agrobacterium-mediated transgene and CRISPR/Cas9 gene editing of broccoli. In contrast to previous studies, we found that 5 mg/L hygromycin B was more advantageous for the selection of resistant broccoli sprouts, and genotype 19B42 reached the highest transformation rate of 26.96%, which is higher than that in Brassica oleracea crops. In addition, the inbred line 19B42 successfully achieved high genetic transformation of overexpression, RNAi and CRISPR/Cas9 vectors; thus, it is powerful recipient material for the genetic transformation of broccoli. Subcellular localization proved that the glucoraphanin metabolism-related gene Bol031350 and clubroot resistance gene CRa were both expressed in the cytoplasm and nucleus, which provided a scientific basis for studying the regulation of glucosinolate metabolism and clubroot resistance in cruciferous crops. Therefore, these findings will provide new insight into the improvement of the genetic transformation and molecular breeding of Brassica oleracea crops.

Synthesis and characterization of copper oxide nanoparticles: its influence on corn (Z. mays) and wheat (Triticum aestivum) plants by inoculation of Bacillus subtilis

Nanotechnology is now playing an emerging role in green synthesis in agriculture as nanoparticles (NPs) are used for various applications in plant growth and development. Copper is a plant micronutrient; the amount of copper oxide nanoparticles (CuONPs) in the soil determines whether it has positive or adverse effects. CuONPs can be used to grow corn and wheat plants by combining Bacillus subtilis. In this research, CuONPs were synthesized by precipitation method using different precursors such as sodium hydroxide (0.1 M) and copper nitrate (Cu(NO₃)₂) having 0.1 M concentration with a post-annealing method. The NPs were characterized through X-ray diffraction (XRD), scanning electron microscope (SEM), and ultraviolet (UV) visible spectroscopy. Bacillus subtilis is used as a potential growth promoter for microbial inoculation due to its prototrophic nature. The JAR experiment was conducted, and the growth parameter of corn (Z. mays) and wheat (Triticum aestivum) was recorded after 5 days. The lab assay evaluated the germination in JARs with and without microbial inoculation under CuONP stress at different concentrations (25 and 50 mg). The present study aimed to synthesize CuONPs and systematically investigate the particle size effects of copper (II) oxide (CuONPs) (< 50 nm) on Triticum aestivum and Z. mays. In our results, the XRD pattern of CuONPs at 500 °C calcination temperature with monoclinic phase is observed, with XRD peak intensity slightly increasing. The XRD patterns showed that the prepared CuONPs were extremely natural, crystal-like, and nano-shaped. We used Scherrer's formula to calculate the average size of the particle, indicated as 23 nm. The X-ray diffraction spectrum of synthesized materials and SEM analysis show that the particles of CuONPs were spherical in nature. The results revealed that the synthesized CuONPs combined with Bacillus subtilis used in a field study provided an excellent result, where growth parameters of Z. Mays and Triticum aestivum such as root length, shoot length, and plant biomass was improved as compared to the control group.

Harnessing plant viruses in the metagenomics era: from the development of infectious clones to applications

Recent metagenomic studies which focused on virus characterization in the entire plant environment have revealed a remarkable viral diversity in plants. The exponential discovery of viruses also requires the concomitant implementation of high-throughput methods to perform their functional characterization. Despite several limitations, the development of viral infectious clones remains a method of choice to understand virus biology, their role in the phytobiome, and plant resilience. Here, we review the latest approaches for efficient characterization of plant viruses and technical advances built on high-throughput sequencing and synthetic biology to streamline assembly of viral infectious clones. We then discuss the applications of plant viral vectors in fundamental and applied plant research as well as their technical and regulatory limitations, and we propose strategies for their safer field applications.

Shoot-root signal circuit: Phytoremediation of heavy metal contaminated soil

High concentrations of heavy metals in the environment will cause serious harm to ecosystems and human health. It is urgent to develop effective methods to control soil heavy metal pollution. Phytoremediation has advantages and potential for soil heavy metal pollution control. However, the current hyperaccumulators have the disadvantages of poor environmental adaptability, single enrichment species and small biomass. Based on the concept of modularity, synthetic biology makes it possible to design a wide range of organisms. In this paper, a comprehensive strategy of "microbial biosensor detection - phytoremediation - heavy metal recovery" for soil heavy metal pollution control was proposed, and the required steps were modified by using synthetic biology methods. This paper summarizes the new experimental methods that promote the discovery of synthetic biological elements and the construction of circuits, and combs the methods of producing transgenic plants to facilitate the transformation of constructed synthetic biological vectors. Finally, the problems that should be paid more attention to in the remediation of soil heavy metal pollution based on synthetic biology were discussed.

CRISPR-Cas: A robust technology for enhancing consumer-preferred commercial traits in crops

The acceptance of new crop varieties by consumers is contingent on the presence of consumer-preferred traits, which include sensory attributes, nutritional value, industrial products and bioactive compounds production. Recent developments in genome editing technologies provide novel insight to identify gene functions and improve the various qualitative and quantitative traits of commercial importance in plants. Various conventional as well as advanced gene-mutagenesis techniques such as physical and chemical mutagenesis, CRISPR-Cas9, Cas12 and base editors are used for the trait improvement in crops. To meet consumer demand, breakthrough biotechnologies, especially CRISPR-Cas have received a fair share of scientific and industrial interest, particularly in plant genome editing. CRISPR-Cas is a versatile tool that can be used to knock out, replace and knock-in the desired gene fragments at targeted locations in the genome, resulting in heritable mutations of interest. This review highlights the existing literature and recent developments in CRISPR-Cas technologies (base editing, prime editing, multiplex gene editing, epigenome editing, gene delivery methods) for reliable and precise gene editing in plants. This review also discusses the potential of gene editing exhibited in crops for the improvement of consumer-demanded traits such as higher nutritional value, colour, texture, aroma/flavour, and production of industrial products such as biofuel, fibre, rubber and pharmaceuticals. In addition, the bottlenecks and challenges associated with gene editing system, such as off targeting, ploidy level and the ability to edit organelle genome have also been discussed.

Strategic nanoparticle-mediated plant disease resistance

Nanotechnology is a promising means for development of sustainable agriculture while the study of nanoparticle-mediated plant disease resistance is still in its primary stage. Nanotechnology has shown great promise in regulating: the content of secondary metabolites, inducing disease resistance genes, delivering hormones, delivering biomolecules (such as: nucleotides, proteins, and activators), and obtaining transgenic plants to resist plant diseases. In this review, we conclude its versatility and applicability in disease management strategies and diagnostics and as molecular tools. With the advent of new biotechnologies (e.g. de novo regeneration, CRISPR/Cas9, and GRF4-GIF1 fusion protein), we discuss the potential of nanoparticles as an optimal platform to deliver biomolecules to plants for genetic engineering. In order to ensure the safe use and social acceptance of plant nanoparticle technology, its adverse effects are discussed, including the risk of transferring nanoparticles through the food chain.

Strategies for genotype-flexible plant transformation

Recent advances in the genome-editing tools have demonstrated a great potential for accelerating functional genomics and crop trait improvements, but the low efficiency and genotype dependence in plant transformation hinder practical applications of such revolutionary tools. Morphogenic transcription factors (MTFs) such as Baby boom, Wuschel2, GROWTH-REGULATING FACTOR5, GROWTH-REGULATING FACTOR4 and its cofactor GRF-INTERACTING FACTOR1, and Wuschel-homeobox 5 related have been shown to greatly enhance plant transformation efficiency and expand the range of amenable species and genotypes. This review will summarize recent advancements in plant transformation technologies with an emphasis on the strategies developed for genotype-flexible transformation methods utilizing MTFs for both monocots and dicot plant species. We highlight several breakthrough studies that demonstrated a wide range of applicability.

Making small molecules in plants: A chassis for synthetic biology-based production of plant natural products

Plant natural products have been extensively exploited in food, medicine, flavor, cosmetic, renewable fuel, and other industrial sectors. Synthetic biology has recently emerged as a promising means for the cost-effective and sustainable production of natural products. Compared with engineering microbes for the production of plant natural products, the potential of plants as chassis for producing these compounds is underestimated, largely due to challenges encountered in engineering plants. Knowledge in plant engineering is instrumental for enabling the effective and efficient production of valuable phytochemicals in plants, and also paves the way for a more sustainable future agriculture. In this manuscript, we briefly recap the biosynthesis of plant natural products, focusing primarily on industrially important terpenoids, alkaloids, and phenylpropanoids. We further summarize the plant hosts and strategies that have been used to engineer the production of natural products. The challenges and opportunities of using plant synthetic biology to achieve rapid and scalable production of high-value plant natural products are also discussed.

Applications of CRISPR/Cas genome editing in economically important fruit crops: recent advances and future directions

Fruit crops, consist of climacteric and non-climacteric fruits, are the major sources of nutrients and fiber for human diet. Since 2013, CRISPR/Cas (Clustered Regularly Interspersed Short Palindromic Repeats and CRISPR-Associated Protein) genome editing system has been widely employed in different plants, leading to unprecedented progress in the genetic improvement of many agronomically important fruit crops. Here, we summarize latest advancements in CRISPR/Cas genome editing of fruit crops, including efforts to decipher the mechanisms behind plant development and plant immunity, We also highlight the potential challenges and improvements in the application of genome editing tools to fruit crops, including optimizing the expression of CRISPR/Cas cassette, improving the delivery efficiency of CRISPR/Cas reagents, increasing the specificity of genome editing, and optimizing the transformation and regeneration system. In addition, we propose the perspectives on the application of genome editing in crop breeding especially in fruit crops and highlight the potential challenges. It is worth noting that efforts to manipulate fruit crops with genome editing systems are urgently needed for fruit crops breeding and demonstration.

Retrotransposons: How the continuous evolutionary front shapes plant genomes for response to heat stress

Long terminal repeat retrotransposons (LTR retrotransposons) are the most abundant group of mobile genetic elements in eukaryotic genomes and are essential in organizing genomic architecture and phenotypic variations. The diverse families of retrotransposons are related to retroviruses. As retrotransposable elements are dispersed and ubiquitous, their "copy-out and paste-in" life cycle of replicative transposition leads to new genome insertions without the excision of the original element. The overall structure of retrotransposons and the domains responsible for the various phases of their replication is highly conserved in all eukaryotes. The two major superfamilies of LTR retrotransposons, Ty1/Copia and Ty3/Gypsy, are distinguished and dispersed across the chromosomes of higher plants. Members of these superfamilies can increase in copy number and are often activated by various biotic and abiotic stresses due to retrotransposition bursts. LTR retrotransposons are important drivers of species diversity and exhibit great variety in structure, size, and mechanisms of transposition, making them important putative actors in genome evolution. Additionally, LTR retrotransposons influence the gene expression patterns of adjacent genes by modulating potential small interfering RNA (siRNA) and RNA-directed DNA methylation (RdDM) pathways. Furthermore, comparative and evolutionary analysis of the most important crop genome sequences and advanced technologies have elucidated the epigenetics and structural and functional modifications driven by LTR retrotransposon during speciation. However, mechanistic insights into LTR retrotransposons remain obscure in plant development due to a lack of advancement in high throughput technologies. In this review, we focus on the key role of LTR retrotransposons response in plants during heat stress, the role of centromeric LTR retrotransposons, and the role of LTR retrotransposon markers in genome expression and evolution.

Potential of nanobiosensor in sustainable agriculture: the state-of-art

A rapid surge in world population leads to an increase in worldwide demand for agricultural products. Nanotechnology and its applications in agriculture have appeared as a boon to civilization with enormous potential in transforming conventional farming practices into redefined farming activities. Low-cost portable nanobiosensors are the most effective diagnostic tool for the rapid on-site assessment of plant and soil health including plant biotic and abiotic stress level, nutritional status, presence of hazardous chemicals in soil, etc. to maintain proper farming and crop productivity. Nanobiosensors detect physiological signals and convert them into standardized detectable signals. In order to achieve a reliable sensing analysis, nanoparticles can aid in signal amplification and sensor sensitivity by lowering the detection limit. The high selectivity and sensitivity of nanobiosensors enable early detection and management of targeted abnormalities. This study identifies the types of nanobiosensors according to the target application in agriculture sector.

Recent advances in crop transformation technologies

Agriculture is experiencing a technological inflection point in its history, while also facing unprecedented challenges posed by human population growth and global climate changes. Key advancements in precise genome editing and new methods for rapid generation of bioengineered crops promise to both revolutionize the speed and breadth of breeding programmes and increase our ability to feed and sustain human population growth. Although genome editing enables targeted and specific modifications of DNA sequences, several existing barriers prevent the widespread adoption of editing technologies for basic and applied research in established and emerging crop species. Inefficient methods for the transformation and regeneration of recalcitrant species and the genotype dependency of the transformation process remain major hurdles. These limitations are frequent in monocotyledonous crops, which alone provide most of the calories consumed by human populations. Somatic embryogenesis and de novo induction of meristems - pluripotent groups of stem cells responsible for plant developmental plasticity - are essential strategies to quickly generate transformed plants. Here we review recent discoveries that are rapidly advancing nuclear transformation technologies and promise to overcome the obstacles that have so far impeded the widespread adoption of genome editing in crop species.

Clay nanoparticles efficiently deliver small interfering RNA to intact plant leaf cells

RNA interference is triggered in plants by the exogenous application of double-stranded RNA or small interfering RNA (siRNA) to silence the expression of target genes. This approach can potentially provide insights into metabolic pathways and gene function and afford plant protection against viruses and other plant pathogens. However, the effective delivery of biomolecules such as siRNA into plant cells is difficult because of the unique barrier imposed by the plant cell wall. Here, we demonstrate that 40-nm layered double hydroxide (LDH) nanoparticles are rapidly taken up by intact Nicotiana benthamiana leaf cells and by chloroplasts, following their application via infiltration. We also describe the distribution of infiltrated LDH nanoparticles in leaves and demonstrate their translocation through the apoplast and vasculature system. Furthermore, we show that 40-nm LDH nanoparticles can greatly enhance the internalization of nucleic acids by N. benthamiana leaf cells to facilitate siRNA-mediated downregulation of targeted transgene mRNA by >70% within 1 day of exogenous application. Together, our results show that 40-nm LDH nanoparticle is an effective platform for delivery of siRNA into intact plant leaf cells.

Precision genome editing in plants using gene targeting and prime editing: existing and emerging strategies

Precise modification of plant genomes, such as seamless insertion, deletion, or replacement of DNA sequences at a predefined site, is a challenging task. Gene targeting (GT) and prime editing are currently the best approaches for this purpose. However, these techniques are inefficient in plants, which limits their applications for crop breeding programs. Recently, substantial developments have been made to improve the efficiency of these techniques in plants. Several strategies, such as RNA donor templating, chemically modified donor DNA template, and tandem-repeat homology-directed repair, are aimed at improving GT. Additionally, improved prime editing gRNA design, use of engineered reverse transcriptase enzymes, and splitting prime editing components have improved the efficacy of prime editing in plants. These emerging strategies and existing technologies are reviewed along with various perspectives on their future improvement and the development of robust precision genome editing technologies for plants.

Relaxation of the Plant Cell Wall Barrier via Zwitterionic Liquid Pretreatment for Micelle-Complex-Mediated DNA Delivery to Specific Plant Organelles

Targeted delivery of genes to specific plant organelles is a key challenge for fundamental plant science, plant bioengineering, and agronomic applications. Nanoscale carriers have attracted interest as a promising tool for organelle‐targeted DNA delivery in plants. However, nanocarrier‐mediated DNA delivery in plants is severely hampered by the barrier of the plant cell wall, resulting in insufficient delivery efficiency. Herein, we propose a unique strategy that synergistically combines a cell wall‐loosening zwitterionic liquid (ZIL) with a peptide‐displaying micelle complex for organelle‐specific DNA delivery in plants. We demonstrated that ZIL pretreatment can enhance cell wall permeability without cytotoxicity, allowing micelle complexes to translocate across the cell wall and carry DNA cargo into specific plant organelles, such as nuclei and chloroplasts, with significantly augmented efficiency. Our work offers a novel concept to overcome the plant cell wall barrier for nanocarrier‐mediated cargo delivery to specific organelles in living plants.

An Intein-Mediated Split-nCas9 System for Base Editing in Plants

Virus-assisted delivery of the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system represents a promising approach for editing plant genomes. Among the CRISPR/Cas systems, CRISPR/Cas9 is most widely used; however, to pack the relatively large size of the CRISPR/Cas9 system into viral vectors with confined packaging capacity is challenging. To address this technical challenge, we developed a strategy based on split inteins that splits the required CRISPR/Cas9 components across a dual-vector system. The CRISPR/Cas reassembles into an active form following co-infection to achieve targeted genome editing in plant cells. An intein-mediated split system was adapted and optimized in plant cells by a successful demonstration of split-eYGFPuv expression. Using a plant-based biosensor, we demonstrated for the first time that the split-nCas9 can induce efficient base editing in plant cells. We identified several split sites for future biodesign strategies. Overall, this strategy provides new opportunities to bridge different CRISPR/Cas9 tools including base editor, prime editor, and CRISPR activation with virus-mediated gene editing.

CeO2 nanoparticles improved cucumber salt tolerance is associated with its induced early stimulation on antioxidant system

Salinity is a global issue limiting efficient agricultural production. Nano-enabled plant salt tolerance is a hot topic. However, the role of nanoparticles induced possible early stimulation on antioxidant system in its improved plant salt tolerance is still largely unknown. Here, poly (acrylic) acid coated nanoceria (cerium oxide nanoparticles) (PNC, 7.8 nm, -31 mV) with potent ROS (reactive oxygen species) scavenging ability are used. Compared with control, no significant difference of H₂O₂ and O₂^•─ content, MDA (malondialdehyde) content, relative electric conductivity, and Fv/Fm was found in leaves and/or roots of cucumber before onset of salinity stress, regardless of leaf or root application of PNC. While, before onset of salinity stress, compared with control, the activities of SOD (superoxide dismutase, up to 1.8 folds change), POD (peroxidase, up to 2.5 folds change) and CAT (catalase, up to 2.3 folds change), and the content of GSH (glutathione, up to 3.0 folds change) and ASA (ascorbic acid, up to 2.4 folds change) in leaves and roots of cucumber with PNC leaf spray or root application were significantly increased. RNA seq analysis further confirmed that PNC foliar spray upregulates more genes in leaves over roots than the root application. These results showed that foliar sprayed PNC have stronger early stimulation effect on antioxidant system than the root applied one and leaf are more sensitive to PNC stimulation than root. After salt stress, cucumber plants with foliar sprayed PNC showed better improvement in salt tolerance than the root applied one. Also, plants with foliar sprayed PNC showed significant higher whole plant cerium content than the root applied one after salt stress. In summary, we showed that foliar spray of nanoceria is more optimal than root application in terms of improving cucumber salt tolerance, and this improvement is associated with better stimulation on antioxidant system in plants.

Biopolymeric Nanoparticles-Multifunctional Materials of the Future

Nanotechnology plays an important role in biological research, especially in the development of delivery systems with lower toxicity and greater efficiency. These include not only metallic nanoparticles, but also biopolymeric nanoparticles. Biopolymeric nanoparticles (BPNs) are mainly developed for their provision of several advantages, such as biocompatibility, biodegradability, and minimal toxicity, in addition to the general advantages of nanoparticles. Therefore, given that biopolymers are biodegradable, natural, and environmentally friendly, they have attracted great attention due to their multiple applications in biomedicine, such as drug delivery, antibacterial activity, etc. This review on biopolymeric nanoparticles highlights their various synthesis methods, such as the ionic gelation method, nanoprecipitation method, and microemulsion method. In addition, the review also covers the applications of biodegradable polymeric nanoparticles in different areas-especially in the pharmaceutical, biomedical, and agricultural domains. In conclusion, the present review highlights recent advances in the synthesis and applications of biopolymeric nanoparticles and presents both fundamental and applied aspects that can be used for further development in the field of biopolymeric nanoparticles.

Novel Materials for Urban Farming

Scarcity of natural resources, shifting demographics, climate change, and increasing waste are four major challenges in the quest to feed the exploding world population. These challenges serve as the impetus to harness novel technologies to improve agriculture, productivity, and sustainability. Urban farming has several advantages over conventional farming: higher productivity, improved sustainability, and the ability to provide fresh food all year round. Novel materials are key to accelerating the evolution of urban farming - with their ability to facilitate controlled release of nutrients and pesticides, improved seed health, substrates with better water retention capability, more efficient recycling of agricultural waste, and precise plant health monitoring. Materials science enables environmental sustainability and higher harvest yields in urban farms. Here, Singapore is used as an example of a land-scarce city where urban farming may be the solution for future food production. Potential research directions and challenges in urban farming are highlighted, and how material optimization and innovation drive the development of urban farming to meet national and global food demands is briefly discussed. This review serves as a guide for researchers and a reference for stakeholders of urban farms, policy makers, and other interested parties.