The Arabidopsis Rab protein RABC1 affects stomatal development by regulating lipid droplet dynamics.

Lipid droplets (LDs) are evolutionarily conserved organelles that serve as hubs of cellular lipid and energy metabolism in virtually all organisms. Mobilization of LDs is important in light-induced stomatal opening. However, whether and how LDs are involved in stomatal development remains unknown. We show here that Arabidopsis thaliana LIPID DROPLETS AND STOMATA 1 (LDS1)/RABC1 (At1g43890) encodes a member of the Rab GTPase family that is involved in regulating LD dynamics and stomatal morphogenesis. The expression of RABC1 is coordinated with the different phases of stomatal development. RABC1 targets to the surface of LDs in response to oleic acid application in a RABC1GEF1-dependent manner. RABC1 physically interacts with SEIPIN2/3, two orthologues of mammalian seipin, which function in the formation of LDs. Disruption of RABC1, RABC1GEF1, or SEIPIN2/3 resulted in aberrantly large LDs, severe defects in guard cell vacuole morphology, and stomatal function. In conclusion, these findings reveal an aspect of LD function and uncover a role for lipid metabolism in stomatal development in plants.

COBL7 is required for stomatal formation via regulation of cellulose deposition in Arabidopsis.

As a key regulator of plant photosynthesis, water use efficiency and immunity, stomata are specialized cellular structures that adopt defined shapes. However, our knowledge about the genetic players of stomatal pore formation and stomatal morphogenesis remains limited. Forward genetic screening, positional cloning, confocal and electron microscopy, physiological and pharmacological assays were employed for isolation and characterization of mutants and genes. We identified a mutant, dsm1, with impaired cytokinesis and deformed stomata. DSM1 is highly expressed in guard mother cells and guard cells, and encodes COBRA-LIKE 7 (COBL7), a plant-specific glycosylphosphatidylinositol (GPI)-anchored protein. COBRA-LIKE 7 and its closest homologue, COBL8, are first enriched on the forming cell plates during cytokinesis, and then their subcellular distribution and abundance change are correlated with the progressive stages of stomatal pore formation. Both COBL7 and COBL8 possess an ability to bind cellulose. Perturbing the expression of COBL7 and COBL8 leads to a decrease in cellulose content and inhibition of stomatal pore development. Moreover, we found that COBL7, COBL8 and CSLD5 have synergistic effects on stomatal development and plant growth. Our findings reveal that COBL7 plays a predominant and functionally redundant role with COBL8 in stomatal formation through regulating cellulose deposition and ventral wall modification in Arabidopsis.

BIG coordinates auxin and SHORT ROOT to promote asymmetric stem cell divisions in Arabidopsis roots.

KEY MESSAGE: BIG regulates ground tissue formative divisions by bridging the auxin gradient with SHR abundance in Arabidopsis roots. The formative divisions of cortex/endodermis initials (CEIs) and CEI daughter cells (CEIDs) in Arabidopsis roots are coordinately controlled by the longitudinal auxin gradient and the radial SHORT ROOT (SHR) abundance. However, the mechanism underlying this coordination remains poorly understood. In this study, we demonstrate that BIG regulates ground tissue formative divisions by bridging the auxin gradient with SHR abundance. Mutations in BIG gene repressed cell cycle progression, delaying the formative divisions within the ground tissues and impairing the establishment of endodermal and cortical identities. In addition, we uncovered auxin's suppressive effect on BIG expression, triggering CYCLIND6;1 (CYCD6;1) activation in an SHR-dependent fashion. Moreover, the degradation of RETINOBLASTOMA-RELATED (RBR) is jointly regulated by BIG and CYCD6;1. The loss of BIG function led to RBR protein accumulation, detrimentally impacting the SHR/SCARECROW (SCR) protein complex and the CEI/CEID formative divisions. Collectively, these findings shed light on a fundamental mechanism wherein BIG intricately coordinates the interplay between SHR/SCR and auxin, steering ground tissue patterning within Arabidopsis root tissue.

A Speedy Point Cloud Registration Method Based on Region Feature Extraction in Intelligent Driving Scene.

The challenges of point cloud registration in intelligent vehicle driving lie in the large scale, complex distribution, high noise, and strong sparsity of lidar point cloud data. This paper proposes an efficient registration algorithm for large-scale outdoor road scenes by selecting the continuous distribution of key area laser point clouds as the registration point cloud. The algorithm extracts feature descriptions of the key point cloud and introduces local geometric features of the point cloud to complete rough and fine registration under constraints of key point clouds and point cloud features. The algorithm is verified through extensive experiments under multiple scenarios, with an average registration time of 0.5831 s and an average accuracy of 0.06996 m, showing significant improvement compared to other algorithms. The algorithm is also validated through real-vehicle experiments, demonstrating strong versatility, reliability, and efficiency. This research has the potential to improve environment perception capabilities of autonomous vehicles by solving the point cloud registration problem in large outdoor scenes.

COBL9 and COBL7 synergistically regulate root hair tip growth via controlling apical cellulose deposition.

Root hairs are cylindrical extensions of root epidermal cells that are important for the acquisition of water and minerals, interactions between plant and microbes. The deposition of cell wall materials in the tip enables root hairs to maintain elongation constantly. To date, our knowledge of the regulators that connect the architecture of cell wall and the root hair development remains very limited. Here, we demonstrated that COBL9 and COBL7, two genes of COBRA-Like family in Arabidopsis as well as their counterparts in rice, OsBC1L1 and OsBC1L8, regulate root hair growth. Single mutant cobl9, double mutants cobl7 cobl9 and double mutants osbc1l1 osbc1l8 all displayed prematurely terminated root hair elongation, though at varying levels. COBL7-YFP and COBL9-YFP accumulate prominently in the growing tips of newly emerged root hairs. Furthermore, cobl9, cobl7 cobl9 and osbc1l1 osbc1l8 mutants were defective in the enrichment of cellulose in the tips of the growing root hairs. We also discovered that overexpression of COBL9 could promote root hair elongation and salinity tolerance. Taken together, these results provide compelling evidence that the polarized COBL7 and COBL9 in the tip of the emerging root hairs have conserved roles in regulating root hair development and stress adaptation in dicots and monocots.

OsBC1L1 and OsBC1L8 function in stomatal development in rice.

Stomata that are bordered by pairs of guard cells are specialized for regulating gas exchange and transpiration in plants. The stomatal morphology of grass is unique, characterized by two dumbbell-shaped guard cells flanked by two lateral subsidiary cells. This morphology and developmental pattern enable grass stomata to respond to environmental signals efficiently. In this study, we demonstrated that knockout either OsBC1L1 or OsBC1L8, two close homologs of OsBC1L family causes no discernible defects in rice stomatal development, however, the double knockout mutant osbc1l1 osbc1l8 exhibits excess stomatal production and stomatal clustering. OsBC1L1 overexpression also causes abnormal stomatal patterning in rice. Moreover, osbc1l1 osbc1l8 has many defective stomata complexes with only one subsidiary cell. The expression of OsSPCH2 and OsFAMA, two genes key to stomatal development is both down-regulated in osbc1l1 osbc1l8. In contrast, overexpressing OsBC1L1 suppresses only the expression of OsSPCH2. Both OsBC1L1 and OsBC1L8 could be detected to be localized at the cell plate and plasma membrane during cell division of guard mother cells and subsidiary mother cells. Taken together, these results suggest that OsBC1L1 and OsBC1L8 play essential roles in the development of rice stomatal complex likely through their involvement in cell reproduction.

Ratiometric fluorescence determination of alkaline phosphatase activity based on dual emission of bovine serum albumin-stabilized gold nanoclusters and the inner filter effect.

A novel and convenient method for the ratiometric fluorescence detection of alkaline phosphatase (ALP) activity was proposed based on dual emission of bovine serum albumin-templated gold nanoclusters (BSA-AuNCs) and the mechanism of the inner filter effect between BSA-AuNCs and p-nitrophenol (PNP). First, ALP catalyzed the hydrolysis of the substrate p-nitrophenyl phosphate (PNPP) to produce PNP. PNP effectively quenched the emission peak of BSA-AuNCs at 410 nm because of the overlap in absorbance feature of PNP and the fluorescence spectrum of BSA-AuNCs, and the peak at 650 nm was almost unaffected. Thus, a sensitive ratiometric method for detection of ALP activity was developed using the fluorescence intensity of BSA-AuNCs at 650 nm as a reference signal. ALP activity versus the ratio of fluorescence intensities at 410 and 650 nm showed good linearity between 0.2 and 5 mU mL-1 (R2 = 0.9931) and high sensitivity with a detection limit of 0.03 mU mL-1 (S/N = 3). The developed sensing method was successfully applied to investigate ALP inhibitors and detect ALP in serum samples.

Entrapment of horseradish peroxidase into nanometer-scale metal-organic frameworks: a new nanocarrier for signal amplification in enzyme-linked immunosorbent assay.

Horseradish peroxidase (HRP) was highly loaded into large holes of nanometer-scale metal-organic frameworks (i.e., PCN-333(Al)) for signal amplification in enzyme-linked immunosorbent assay (ELISA). The enzyme-labeled antibody complex prepared using nanometer-scale PCN-333(Al) maintained a high catalytic efficiency. Its Vm and Kcat values with 3,3',5,5'-Tetramethylbenzidine (TMB)-H2O2 as substrates were 4.84 × 10-5 mM/s and 4.84 × 104 min-1, respectively. We demonstrated an HRP@PCN-333 signal amplification strategy for colorimetric assay of human prostate-specific antigen (PSA). The linear range of PSA detection by using this method was 15-165 pg/mL, and the limit of detection was 6 pg/mL (S/N = 3), indicating the potential application of this method in detecting disease markers under clinical conditions. The presented strategy exhibited the characteristics of significantly increased amount of labeled enzymes, improved stability and utilization of enzymes, simple preparation process of enzyme-labeled antibodies, and low cost.

Effects of shade stress on turfgrasses morphophysiology and rhizosphere soil bacterial communities.

BACKGROUND: The shade represents one of the major environmental limitations for turfgrass growth. Shade influences plant growth and alters plant metabolism, yet little is known about how shade affects the structure of rhizosphere soil microbial communities and the role of soil microorganisms in plant shade responses. In this study, a glasshouse experiment was conducted to examine the impact of shade on the growth and photosynthetic capacity of two contrasting shade-tolerant turfgrasses, shade-tolerant dwarf lilyturf (Ophiopogon japonicus, OJ) and shade-intolerant perennial turf-type ryegrass (Lolium perenne, LP). We also examined soil-plant feedback effects on shade tolerance in the two turfgrass genotypes. The composition of the soil bacterial community was assayed using high-throughput sequencing. RESULTS: OJ maintained higher photosynthetic capacity and root growth than LP under shade stress, thus OJ was found to be more shade-tolerant than LP. Shade-intolerant LP responded better to both shade and soil microbes than shade-tolerant OJ. The shade and live soil decreased LP growth, but increased biomass allocation to shoots in the live soil. The plant shade response index of LP is higher in live soil than sterile soil, driven by weakened soil-plant feedback under shade stress. In contrast, there was no difference in these values for OJ under similar shade and soil treatments. Shade stress had little impact on the diversity of the OJ and the LP bacterial communities, but instead impacted their composition. The OJ soil bacterial communities were mostly composed of Proteobacteria and Acidobacteria. Further pairwise fitting analysis showed that a positive correlation of shade-tolerance in two turfgrasses and their bacterial community compositions. Several soil properties (NO3--N, NH4+-N, AK) showed a tight coupling with several major bacterial communities under shade stress. Moreover, OJ shared core bacterial taxa known to promote plant growth and confer tolerance to shade stress, which suggests common principles underpinning OJ-microbe interactions. CONCLUSION: Soil microorganisms mediate plant responses to shade stress via plant-soil feedback and shade-induced change in the rhizosphere soil bacterial community structure for OJ and LP plants. These findings emphasize the importance of understanding plant-soil interactions and their role in the mechanisms underlying shade tolerance in shade-tolerant turfgrasses.

Influence of Addition of Ti Particles and Processing Condition on Microstructure and Properties of Selectively Laser-Melted Invar 36 Alloy.

Invar 36 exhibits extremely low thermal expansion coefficients at low temperatures but also low yield strength (YS), which greatly restricts its application as a structural material. In this study, a small fraction of pure titanium powder particles was added into Invar 36 by powder mixing and selective laser melting (SLM) with the aim of further improving tensile strengths of Invar 36. It was found that increased laser power led to increased grain size and to slight decrease in YS in Invar 36. During SLM, amorphous SiO2 nanoparticles were formed and homogeneously distributed in Invar 36. With the addition of 2 at% Ti powder particles, grains became larger and the crystallographic texture along <001> and <111> increased to some extent. Moreover, the bottom of solidified melt pools was segregated with Ti while the matrix was homogeneously decorated by a great number of nano-sized spherical Ti2O3 particles. These particles were found to have effectively impeded dislocation motion during plastic deformation, leading to significant improvement in 0.2% YS and ultimate tensile strength. The above precipitation led to consumption of a small amount of Ni from the matrix, which caused a minor compromise in thermal expansion properties. Nonetheless, the newly synthesized Invar 36-Ti alloy still exhibits low thermal expansion coefficients at low temperatures and remarkably enhanced tensile strengths.

Hierarchical Distributed Adaptive Fault-Tolerant Control of Nonlinear Fractional-Order Multiagent Systems With Faults and Periodic Disturbances Using Event-Triggered Communication.

This article presents a distributed fault-tolerant control (FTC) scheme for nonlinear fractional-order (FO) multiagent systems (MASs) with the order lying in (0, 1, such that the proposed control architecture can be directly applied to both FO and integer-order (IO) systems without any modifications. To handle the unexpected actuator faults encountered by the FO MASs, a hierarchical FTC mechanism is developed for each system by constructing an event-triggered distributed FO estimator at the upper layer to estimate the leader system's output via conditionally triggered neighboring information, and an FTC unit at the lower layer to counteract the loss-of-effectiveness faults via Nussbaum function with FO criteria. To further address the unknown nonlinear functions involving bias faults and periodic disturbances, the Fourier series expansion technique is used to construct the input variables of fuzzy neural networks (FNNs), such that the FNNs with dynamically adjusted weight matrices, centers, and widths can be developed for each FO system to act as the learning module. It is shown by FO Lyapunov stability analysis that all follower systems can track the leader system against faults and periodic disturbances. Simulation results on FO systems and hardware-in-the-loop experiment results on IO fixed-wing unmanned aerial vehicles show the extensive feasibility of the developed scheme.

Key quality factors for Chinese herbal medicines entering the EU market.

Chinese herbal medicines (CHMs) have unique advantages in the prevention and treatment of diseases, which are widely recognized in the world. More and more CHMs are becoming increasingly popular in the international markets. However, the quality control of CHMs is a significant issue for their acceptance and recognition in the international market. This review mainly focuses on the quality requirements for CHMs to enter the European Union (EU) market. Both Chinese and European regulations and quality controls are compared. Firstly, the EU medicinal regulatory system and relevant regulations were reviewed. Secondly, the key factors of the quality control of CHMs, including Chinese herbal drugs, extracts and products were compared with those of European herbal medicines in the EU market. Subsequently, three main registration routes for herbal medicinal products including Chinese herbal medicinal products entering the EU were introduced. Furthermore, the legal status of traditional Chinese medicine granules in the EU was also discussed. Through the comparison of the key quality factors for CHMs in China and the EU, the similarities and differences in terms of quality requirements and regulations are addressed, which provides a reference for the development of CHMs into the EU market.

Market access for Chinese herbal medicinal products in Europe-A ten-year review of relevant products, policies, and challenges.

BACKGROUND: With increased consumer demand in Europe for natural and efficacious health products, the use of herbal products in the market is rising. Products of Chinese herbal medicine (CHM) could greatly expand European consumer options; however, only seven herbal medicinal products (HMPs) based on CHM formulae have been registered in the European Union (EU) since 2012. PURPOSE: This study reviews the ten-year registration status of HMPs based on CHM formulae in Europe and identifies major challenges and possible solutions for pharmaceutical companies seeking market access for new HMPs. METHODS: An overview of relevant EU regulations identifies pathways to market access in EU countries for CHM products. A discussion of successful attempts to register HMPs based on CHM formulae since 2012 highlights specific challenges that applicants can expect to face. RESULTS: CHM products can enter the EU market as HMPs through the full or well-established use marketing authorization, or through the simplified registration procedure. Alternatively, some CHM products have entered the market as dietary supplements, nutritional foods, and agricultural products; however, under these categories, claims for medicinal use cannot be advertised. Since the registration of the first CHM product, Diao Xin Xue Kang (with the single component of Dioscorea nipponica rhizome), in 2012, only six other HMPs based on CHM formulae have been successfully registered. Among these, four are mono-component products. The remaining two products contain combinations of several herbal ingredients. It is more difficult to register combination products than mono-component products, due to their more complex composition and differences in registration requirements (esp. concerning establishing indications) in China and Europe. CONCLUSIONS: To promote the successful registration of CHM products in Europe, pharmaceutical companies are advised to: demonstrate full control of, and the ability to test, their supply chain and manufacturing procedures following the guidance of European competent authorities; carefully adhere to all steps of the registration process and advices from European competent authorities; take the medication habits and pharmaceutical needs of European market into consideration; and establish collaboration with European local organizations, as appropriate.