(Nanowerk Spotlight) Plant diseases destroy up to 40% of global food crops, threatening food security and agricultural sustainability. While plants naturally resist many diseases, their defenses often fail against aggressive pathogens. Current solutions rely heavily on chemical pesticides, which can harm beneficial organisms, contaminate soil and water, and lead to resistant pathogens. This creates an urgent need for safer methods to protect crops.
Scientists have attempted to boost plant immunity using various approaches, from breeding resistant varieties to developing biological control agents. Nanomaterials emerged as a promising option in the past decade, offering precise ways to interact with plant cells. However, many early nanomaterials proved too toxic, unstable, or impractical for agricultural use. Carbon-based materials showed initial promise but struggled with consistent effectiveness and production scalability.
A significant shift occurred in 2011 with the discovery of MXenes, materials made of ultra-thin layers of transition metal carbides, nitrides, or carbonitrides that can be engineered to have specific properties. These materials have shown promise in medical applications, such as drug delivery and bioimaging, due to their tunable properties and potential biocompatibility, although their safety depends on factors like size, surface modification, and dosage. This growing interest has led researchers to explore their potential applications in plants, particularly in areas like nutrient delivery and agricultural sensing, though this field is still in its early stages.
Aqueous colloidal preparation and physicochemical characterization of Ti3C2Tx MXene. A–F) Schematic model depicting the overall workflow of the study, sample preparation and sterilization procedures, and representation of the atomic structure of the aqueous nanoflakes dispersion. Briefly, Ti3C2Tx powder was dispersed in Milli-Q water at 500 µgmL−1, followed by stirring, bath ultrasonication, and autoclave treatment of the sheets to obtain a final structure. This treatment led the flakes to readily form colloids, including Ti3C2Tx nanosheet-derived quantum dots and crystalline surface titanium oxide particles. G) The SEM image of these Ti3C2Tx MXene showed a typical separation of the nanosheets with an interlayer distance ranging from ≈30 to 150 nm. HI) TEM images and the associated SAED pattern of these nanosheets further demonstrated their multilayeredmorphology and hexagonalvcrystalline structure. SEM images of J) these Ti3C2Tx MXene powder shelf-stored at normal room conditions, including partial surface oxidation, andvK) autoclaved Ti3C2Tx dispersions when spin-coated and dried at room temperature. L, inset) TEM images of autoclaved aqueous collides, including 2DvTi3C2Tx-based nanosheets and derived 0D quantum dots as well as surface titanium oxides/particles at different magnifications. M–O) EDS area scanningvand elementals mapping analysis of pristine Ti3C2Tx MXene powder display the compositional chemical elements in the structure of this material.vP,Q) The XRD analysis of Ti3C2Tx powder showing phase pattern of these nanosheets at 2𝜃 of 5° to 80°. R,S) GIXRD of as-treated Ti3C2Tx MXene sheetsvafter spin-coating/drying at room temperature. The main characteristic peak (002) in the XRD spectra of these materials represents their typical phasevstructure and is aligned with the previous reports of Ti3C2Tx MXene in the literature. There is no standard JCPDS or exactly matched ICSD referencevnumbers available yet for Ti3C2Tx MXene due to its complex structure and variable surface terminals. (Image: Reprinted from DOI:10.1002/adfm.202411869, CC BY) (click on image to enlarge)
The team tested their solution on multiple plant species, applying small amounts to leaves. Within hours, treated plants produced defensive compounds called reactive oxygen species – an early warning signal that activates plant immune responses. Notably, this occurred at concentrations as low as 40 micrograms per milliliter, about one-thousandth the amount needed for traditional treatments.
The results showed remarkable breadth of protection. Plants treated with the solution reduced tobacco mosaic virus infection by over 90% compared to untreated plants. The material also stopped the growth of harmful bacteria like Pseudomonas syringae and prevented fungal infections from Fusarium graminearum, demonstrating protection against all major types of plant pathogens.
Genetic analysis revealed why the treatment worked so well. The MXene solution activated over 200 genes involved in plant defense within two hours of application. These included genes that strengthen cell walls, produce antimicrobial compounds, and prepare the plant for future attacks. Unlike harsh chemicals that force plants to redirect energy from growth to defense, this treatment actually enhanced photosynthesis and development.
The material’s effectiveness stems from its unique structure. The nanosheets carry a negative electrical charge that allows them to bind to both plant cells and pathogens. On plant cells, this binding triggers immune responses without causing damage. On pathogens, it disrupts their cell membranes, preventing infection. The material also helps regulate plant hormones that balance growth with defense.
Safety testing showed encouraging results. The nanosheets broke down naturally over time and did not accumulate in plant tissues. At effective doses, they caused no harm to plant cells or soil organisms. The production process proved relatively simple and scalable, making it practical for agricultural suppliers to manufacture and farmers to apply using standard spraying equipment.
Earlier attempts at using nanomaterials in agriculture often failed because the materials were too expensive to produce, required complex application methods, or accumulated in soil. Some showed promise in laboratory tests but degraded too quickly in field conditions. Others protected against specific diseases but proved toxic to beneficial insects or soil microorganisms. The new MXene solution overcomes these challenges through its stable water-based formulation and natural degradation process.
The technology offers practical benefits for different types of farming operations. Commercial farmers could spray the solution during routine crop maintenance, potentially reducing pesticide applications by strengthening plants’ natural defenses. Organic farmers gain a new tool that aligns with certification requirements while providing broad-spectrum protection. Greenhouse operations could use it preventively to reduce disease pressure in high-value crops.
The material’s ease of use stands out – farmers can apply it with existing spray equipment, store it in standard conditions, and integrate it into regular crop management programs. Its low required concentration means a small amount protects large areas, making it economically viable for both small and large-scale farming.
The researchers are now testing the material on major crop species under field conditions. While this work continues, the current results demonstrate how advanced materials science can provide farmers with practical tools to protect crops while reducing chemical inputs. As agriculture faces increasing pressure to become more sustainable, solutions that work with plants’ natural defense systems offer a promising path forward.
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