Daisuke Urano

Designing biomaterials compatible with plants and specific payloads enables new technologies for precision agriculture, including targeted and dose‐controlled agrochemical delivery that overcomes the runoff, drift, and cuticular exclusion limiting conventional methods. However, broader implementation requires a systematic understanding of the complex interactions among payloads, biomaterial properties, and plant responses to establish design principles that support a sustained biotic–abiotic interface. Using microneedles made of different polymers and microstructures, this study investigates plant–biomaterial interactions to develop effective compound delivery strategies. Biodegradation studies show that microneedle biomaterials impart distinct mechanical strength, hydrophilicity, and surface charge, influencing the release of bioactive cargo. Transcriptomic analyses reveal a largely shared acute response to microneedle injection, with some material‐ or structure‐dependent variation in immunity and metabolism. Mid‐term biochemical responses show corresponding differences in membrane integrity and antioxidant activity. Despite these responses, microneedle treatments caused minimal effects on plant growth, chlorophyll content, stomatal conductance, and quantum efficiency of photosystem II. Finally, we demonstrate how biomaterial properties influence agrochemical delivery using hydrophilic plant growth regulator gibberellic acid (GA ₃ ) and hydrophobic herbicide pelargonic acid (PA), into tomato and lettuce, respectively. These findings establish principles for engineering plant‐biomaterial interfaces to accommodate payloads with diverse characteristics while ensuring plant safety.

Designing biomaterials compatible with plants and specific payloads enables new technologies for precision agriculture, including targeted and efficient agrochemical delivery. However, broader implementation requires a systematic understanding of the complex interactions among payloads, biomaterial properties, and plant responses to establish foundational design principles that support a sustained biotic–abiotic interface. Using microneedles made of different polymers and microstructures, this study investigates plant–biomaterial interactions to develop effective compound delivery strategies. Biodegradation studies show that microneedle biomaterials impart distinct mechanical strength, hydrophilicity, and surface charge, which influence the release profiles of bioactive cargo. Transcriptomic analyses following microneedle injection reveal mostly universal, but some variable acute responses related to immunity and metabolism, depending on inherent biomaterial properties. Despite these responses, microneedle treatments caused minimal effects on plant growth, chlorophyll content, stomatal conductance, and quantum efficiency of photosystem II. Finally, we demonstrate how biomaterial properties influence the delivery of agrochemicals with distinct chemical and functional characteristics, using hydrophilic plant growth regulator gibberellic acid (GA3) and hydrophobic herbicide pelargonic acid (PA), into tomato and lettuce, supporting the broad applicability of technology. These findings establish principles for engineering plant-biomaterial interfaces to accommodate payloads with diverse characteristics while ensuring plant safety.

Hyperspectral imaging is an imaging technique that allows for acquisition of high-resolution spectral information beyond that of the visible spectrum. When applied to plants, it effectively enables non-invasive characterization of physiological status and has been widely used in agricultural settings. Marchantia is a model bryophyte species whose flat morphology and visually distinct stress-response phenotypes makes it an ideal candidate for imaging studies. Here, we provide a comprehensive protocol for hyperspectral imaging for Marchantia plants, which encompasses hardware configuration, data acquisition, and computations processing. This protocol features a streamlined data processing pipeline hosted on a web-based development platform that automates 1) the segmentation of plant area into spatially distinct regions for localized analysis of intra-specimen physiological gradients, and 2) classification of plant pixels based on their spectral signatures. All results are exported as structured CSV files for ease of further analysis as desired by the user.

The broad-spectrum herbicide L-phosphinothricin (PPT) irreversibly inhibits glutamine synthetase (GS) activity. Here we present cationic amino acid transporters (CAT) as mediators of PPT accumulation and susceptibility. Comparative analysis of Arabidopsis thaliana, Marchantia polymorpha, rice, and Klebsormidium nitens reveals conserved responses to GS inhibition, with absence of efficient PPT uptake underlying resistance in M. polymorpha. Transcriptomic analysis identifies four candidate transporters in A. thaliana which, when overexpressed in M. polymorpha, confer varying levels of sensitivity corresponding with PPT accumulation. AtCAT1 and AtCAT5 confer the greatest sensitivities and are required for glutamic acid uptake and endogenous nitrogen metabolism in A. thaliana, and PPT susceptibility. Molecular dynamics simulation of AtCAT5 identifies key residues involved in PPT binding, which induce the rotational flexibility of helices H1 and H6 which form an intracellular access tunnel. These findings highlight the natural diversity underlying PPT accumulation and susceptibility, which can guide herbicide resistance management strategies.

Gamma-aminobutyric acid (GABA) is a metabolite involved in plant growth and stress responses, with its synthesis regulated by glutamate decarboxylase (GAD). Plant GAD enzymes have an autoinhibitory α-helix at the C-terminus, which calmodulin (CaM) binding typically relieves. Eliminating this C-terminal motif usually increases GABA levels in crops. In this case study, we generated a CRISPR/Cas9-edited lettuce line with a 14-amino acid deletion in the C-terminal helix of LsGAD2, the isozyme primarily expressed in most tissues. This targeted truncation removes CaM-binding residues while retaining the key Lys cluster (Lys489, Lys490, Lys491) responsible for autoinhibition, resulting in a significant reduction in GABA content without affecting growth. The LsGAD1/2-ΔC line showed a transcriptomic profile resembling stress responses in the wildtype under unstressed conditions. Reduced GABA levels appeared to upregulate genes involved in stress perception, signalling, and defense-related metabolic and hormonal changes, potentially mediated by WRKY-family transcription factors. Likely due to lower GABA levels and altered defense responses, LsGAD1/2-ΔC plants showed increased Agrobacterium-mediated transient expression of β-glucuronidase. Overall, our study suggests that targeted genetic manipulation of the C-terminal helix of GAD enzymes can reduce GABA levels while enhancing transformation efficiency in lettuce, thus presenting a means for engineering for such purposes.

Recent advancements in plant sensing technologies have significantly improved agricultural productivity while reducing resource inputs, resulting in higher yields by enabling early disease detection, precise diagnostics, and optimized fertilizer and pesticide applications. Each adopted technology offers unique advantages suitable for various farm operations, breeding programs, and laboratory research. This review article first summarizes key target traits, endogenous structures, and metabolites that serve as focal points for plant diagnostic and sensing technologies. Next, conventional plant sensing technologies based on light reflectance and fluorescence, which rely on foliar phytopigments and fluorophores such as chlorophylls are discussed. These methods, along with advanced analytical strategies incorporating machine learning, enable accurate stress detection and classification beyond general assessments of plant health and stress status. Advanced optical techniques such as Fourier transform infrared spectroscopy (FT‐IR) and Raman spectroscopy, which allow specific measurements of various plant metabolites and structural components are then highlighted. Furthermore, the design and applications of nanotechnology chemical sensors capable of highly sensitive and selective detection of specific phytochemicals, including phytohormones and signaling second messengers, which regulate physiological and developmental processes at micro‐ to sub‐micromolar concentrations are introduced. By selecting appropriate sensing methodologies, agricultural production, and relevant research activities can be significantly improved.