Small particles, big effects: How nanoparticles can enhance plant growth in favorable and harsh conditions.

By 2050, the global population is projected to reach 9 billion, underscoring the imperative for innovative solutions to increase grain yield and enhance food security. Nanotechnology has emerged as a powerful tool, providing unique solutions to this challenge. Nanoparticles (NPs) can improve plant growth and nutrition under normal conditions through their high surface-to-volume ratio and unique physical and chemical properties.

Incorporation of Selenium Derived from Nanoparticles into Plant Proteins .

Diets comprising selenium-deficient crops have been linked to immune disorders and cardiomyopathy. Selenium nanoparticles (SeNPs) have emerged as a promising nanoplatform for selenium-biofortified agriculture. However, SeNPs fail to reach field-scale applications due to a poor understanding of the fundamental principles of its behavior.

Magnetite nanoparticle coating chemistry regulates root uptake pathways and iron chlorosis in plants.

Understanding the fundamental interaction of nanoparticles at plant interfaces is critical for reaching field-scale applications of nanotechnology-enabled plant agriculture, as the processes between nanoparticles and root interfaces such as root compartments and root exudates remain largely unclear. Here, using iron deficiency-induced plant chlorosis as an indicator phenotype, we evaluated the iron transport capacity of FeO nanoparticles coated with citrate (CA) or polyacrylic acid (PAA) in the plant rhizosphere. Both nanoparticles can be used as a regulator of plant hormones to promote root elongation, but they regulate iron deficiency in plant in distinctive ways.

NAC1 regulates root ground tissue maturation by coordinating with the SCR/SHR-CYCD6;1 module in Arabidopsis.

Precise spatiotemporal control of the timing and extent of asymmetric cell divisions (ACDs) is essential for plant development. In the Arabidopsis root, ground tissue maturation involves an additional ACD of the endodermis that maintains the inner cell layer as the endodermis and generates the middle cortex to the outside. Through regulation of the cell cycle regulator CYCLIND6;1 (CYCD6;1), the transcription factors SCARECROW (SCR) and SHORT-ROOT (SHR) play critical roles in this process.

Molecular Mechanism of Gibberellins in Mesocotyl Elongation Response to Deep-Sowing Stress in Sweet Maize.

Uneven germination is still a common problem in sweet maize planting. The mesocotyl is a key driver for ground-breaking sweet maize, and deep-sowing has a longer mesocotyl. However, the physiological and molecular mechanisms of sweet maize mesocotyl elongation in response to deep-sowing remain unknown.

Correction: PRH1 mediates ARF7-LBD dependent auxin signaling to regulate lateral root development in Arabidopsis thaliana.

[This corrects the article DOI: 10.1371/journal.pgen.

How plants discern friends from foes.

Microbial-associated molecular pattern (MAMP)-triggered immunity (MTI) is a well-known plant innate immune response to pathogens. Plant commensal microbes have evolved a variety of strategies to interfere with or bypass MTI to establish symbiosis. Recent progress reported by Teixeira et al.

The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators.

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource.

Cell-type action specificity of auxin on Arabidopsis root growth.

The plant hormone auxin plays a critical role in root growth and development; however, the contributions or specific roles of cell-type auxin signals in root growth and development are not well understood. Here, we mapped tissue and cell types that are important for auxin-mediated root growth and development by manipulating the local response and synthesis of auxin. Repressing auxin signaling in the epidermis, cortex, endodermis, pericycle or stele strongly inhibited root growth, with the largest effect observed in the endodermis.

Light participates in the auxin-dependent regulation of plant growth.

Light is the energy source for plant photosynthesis and influences plant growth and development. Through multiple photoreceptors, plant interprets light signals through various downstream phytohormones such as auxin. Recently, Chen et al.

Antagonistic Interaction between Auxin and SA Signaling Pathways Regulates Bacterial Infection through Lateral Root in Arabidopsis.

Pathogen entry into host tissues is a critical and first step in infections. In plants, the lateral roots (LRs) are a potential entry and colonization site for pathogens. Here, using a GFP-labeled pathogenic bacterium Pseudomonas syringae pv.

Plant Sense: The Rise of Calcium Channels.

Although calcium (Ca) elevation triggered by abiotic and biotic stimuli has long been a documented phenomenon in plants, the mechanism underlying the control of Ca spikes remains elusive. Recent progress, reported by Tian et al., Wang et al.

Differentially charged nanoplastics demonstrate distinct accumulation in Arabidopsis thaliana.

Although the fates of microplastics (0.1-5 mm in size) and nanoplastics (<100 nm) in marine environments are being increasingly well studied, little is known about the behaviour of nanoplastics in terrestrial environments, especially agricultural soils. Previous studies have evaluated the consequences of nanoplastic accumulation in aquatic plants, but there is no direct evidence for the internalization of nanoplastics in terrestrial plants.

PIFs coordinate shade avoidance by inhibiting auxin repressor ARF18 and metabolic regulator QQS.

Shade avoidance syndrome (SAS) arises in densely growing plants that compete for light. In Arabidopsis thaliana, phytochrome interacting factor (PIF) proteins link the perception of shade to stem elongation via auxin production. Here, we report that PIFs inhibit the shade-induced expression of AUXIN RESPONSE FACTOR 18 (ARF18), and ARF18 represses auxin signaling.

AtHB7/12 Regulate Root Growth in Response to Aluminum Stress.

Aluminum (Al) stress is a major limiting factor for plant growth and crop production in acid soils. At present, only a few transcription factors involved in the regulation of Al resistance have been characterized. Here, we used reversed genetic approach through phenotype analysis of overexpressors and mutants to demonstrate that AtHB7 and AtHB12, two HD-Zip I transcription factors, participate in Al resistance.

Initiation and maintenance of plant stem cells in root and shoot apical meristems.

Plant stem cells are a small group of cells with a self-renewal capacity and serve as a steady supply of precursor cells to form new differentiated tissues and organs in plants. Root stem cells and shoot stem cells, which are located in the root apical meristem and in the shoot apical meristem, respectively, play a critical role in plant longitudinal growth. These stem cells in shoot and root apical meristems remain as pluripotent state throughout the lifespan of the plant and control the growth and development of plants.

PRH1 mediates ARF7-LBD dependent auxin signaling to regulate lateral root development in Arabidopsis thaliana.

The development of lateral roots in Arabidopsis thaliana is strongly dependent on signaling directed by the AUXIN RESPONSE FACTOR7 (ARF7), which in turn activates LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, LBD18 and LBD29). Here, the product of PRH1, a PR-1 homolog annotated previously as encoding a pathogen-responsive protein, was identified as a target of ARF7-mediated auxin signaling and also as participating in the development of lateral roots. PRH1 was shown to be strongly induced by auxin treatment, and plants lacking a functional copy of PRH1 formed fewer lateral roots.

Non-canonical AUX/IAA protein IAA33 competes with canonical AUX/IAA repressor IAA5 to negatively regulate auxin signaling.

The phytohormone auxin controls plant growth and development via TIR1-dependent protein degradation of canonical AUX/IAA proteins, which normally repress the activity of auxin response transcription factors (ARFs). IAA33 is a non-canonical AUX/IAA protein lacking a TIR1-binding domain, and its role in auxin signaling and plant development is not well understood. Here, we show that IAA33 maintains root distal stem cell identity and negatively regulates auxin signaling by interacting with ARF10 and ARF16.

RLCKs Bridge Plant Immune Receptors and MAPK Cascades.

Receptor-like cytoplasmic kinases (RLCKs) and MAP kinase (MAPK) cascades function downstream of diverse pattern recognition receptors (PRRs) to transduce immune signals. Recent studies identified two MAPK kinase kinases that are directly activated by RLCKs, and filled in a gap in immune signal transduction between PRR activation and the MAPK cascades.

ROS: The Fine-Tuner of Plant Stem Cell Fate.

Reactive oxygen species (ROS) are initially considered to be toxic by-products of aerobic metabolism. However, accumulating evidence has shown that ROS also act as key regulators for the progression of several basic biological processes. Recent studies highlight the key role of ROS in root and shoot stem cell niche maintenance.

Ethylene promotes cadmium-induced root growth inhibition through EIN3 controlled XTH33 and LSU1 expression in Arabidopsis.

Cadmium (Cd) stress is one of the most serious heavy metal stresses limiting plant growth and development. However, the molecular mechanisms underlying Cd-induced root growth inhibition remain unclear. Here, we found that ethylene signalling positively regulates Cd-induced root growth inhibition.

The Root Transition Zone: A Hot Spot for Signal Crosstalk.

The root transition zone (TZ), located between the apical meristem and basal elongation region, has a unique role in root growth and development. The root TZ is not only the active site for hormone crosstalk, but also the perception site for various environmental cues, such as aluminum (Al) stress and low phosphate (Pi) stress. We propose that the root TZ is a hot spot for the integration of diverse inputs from endogenous (hormonal) and exogenous (sensorial) stimuli to control root growth.

PHB3 Maintains Root Stem Cell Niche Identity through ROS-Responsive AP2/ERF Transcription Factors in Arabidopsis.

The root stem cell niche, which is composed of four mitotically inactive quiescent center (QC) cells and the surrounding actively divided stem cells in Arabidopsis, is critical for growth and root development. Here, we demonstrate that the Arabidopsis prohibitin protein PHB3 is required for the maintenance of root stem cell niche identity by both inhibiting proliferative processes in the QC and stimulating cell division in the proximal meristem (PM). PHB3 coordinates cell division and differentiation in the root apical meristem by restricting the spatial expression of ethylene response factor (ERF) transcription factors 115, 114, and 109.

Comparative transcript profiling of maize inbreds in response to long-term phosphorus deficiency stress.

Maize (Zea mays L.) is an important food and energy crop, and low phosphate (Pi) availability is one of the major constraints in maize production worldwide. Plants adapt suitably to acclimate to low Pi stress.