MSH7 confers quantitative variation in pollen fertility and boosts grain yield in maize.

Fertile pollen is critical for the survival, fitness, and dispersal of flowering plants, and directly contributes to crop productivity. Extensive mutational screening studies have been carried out to dissect the genetic regulatory network determining pollen fertility, but we still lack fundamental knowledge about whether and how pollen fertility is controlled in natural populations. We used a genome-wide association study (GWAS) to show that ZmGEN1A and ZmMSH7, two DNA repair-related genes, confer natural variation in maize pollen fertility. Mutants defective in these genes exhibited abnormalities in meiotic or post-meiotic DNA repair, leading to reduced pollen fertility. More importantly, ZmMSH7 showed evidence of selection during maize domestication, and its disruption resulted in a substantial increase in grain yield for both inbred and hybrid. Overall, our study describes the first systematic examination of natural genetic effects on pollen fertility in plants, providing valuable genetic resources for optimizing male fertility. In addition, we find that ZmMSH7 represents a candidate for improvement of grain yield.

Biomimetic Gland Models with Engineered Stratagems.

As extensively distributed tissues throughout the human body, glands play a critical role in various physiological processes. Therefore, the construction of biomimetic gland models in vitro has aroused great interest in multiple disciplines. In the biological field, the researchers focus on optimizing the cell sources and culture techniques to reconstruct the specific structures and functions of glands, such as the emergence of organoid technology. From the perspective of biomedical engineering, the generation of biomimetic gland models depends on the combination of engineered scaffolds and microfluidics, to mimic the in vivo environment of glandular tissues. These engineered stratagems endowed gland models with more biomimetic features, as well as a wide range of application prospects. In this review, we first describe the biomimetic strategies for constructing different in vitro gland models, focusing on the role of microfluidics in promoting the structure and function development of biomimetic glands. After summarizing several common in vitro models of endocrine and exocrine glands, the applications of gland models in disease modelling, drug screening, regenerative medicine, and personalized medicine are enumerated. Finally, we conclude the current challenges and our perspective of these biomimetic gland models.

Inhibition of the maize salt overly sensitive pathway by ZmSK3 and ZmSK4.

Soil salinity is a worldwide problem that adversely affects plant growth and crop productivity. The salt overly sensitive (SOS) pathway is evolutionarily conserved and essential for plant salt tolerance. In this study, we reveal how the maize shaggy/glycogen synthase kinase 3-like kinases ZmSK3 and ZmSK4, orthologs of brassinosteroid insensitive 2 in Arabidopsis thaliana, regulate the maize SOS pathway. ZmSK3 and ZmSK4 interact with and phosphorylate ZmSOS2, a core member of the maize SOS pathway. The mutants defective in ZmSK3 or ZmSK4 are hyposensitive to salt stress, with higher salt-induced activity of ZmSOS2 than that in the wild type. Furthermore, the Ca2+ sensors ZmSOS3 and ZmSOS3-like calcium binding protein 8 (ZmSCaBP8) activate ZmSOS2 to maintain Na+/K+ homeostasis under salt stress and may participate in the regulation of ZmSOS2 by ZmSK3 and ZmSK4. These findings discover the regulation of the maize SOS pathway and provide important gene targets for breeding salt-tolerant maize.

Bee Sting-Inspired Inflammation-Responsive Microneedles for Periodontal Disease Treatment.

Periodontal lesions are common and frustrating diseases that impact life quality. Efforts in this aspect aim at developing local drug delivery systems with better efficacy and less toxicity. Herein, inspired by the sting separation behavior of bees, we conduct novel reactive oxygen species (ROS)-responsive detachable microneedles (MNs) that carry antibiotic metronidazole (Met) for controllable periodontal drug delivery and periodontitis treatment. Benefiting from the needle-base separation ability, such MNs can penetrate through the healthy gingival to reach the gingival sulcus's bottom while offering minimal impact to oral function. Besides, as the drug-encapsulated cores were protected by poly (lactic-co-glycolic acid) (PLGA) shells in MNs, the surrounding normal gingival tissue is not affected by Met, resulting in excellent local biosafety. Additionally, with the ROS-responsive PLGA-thioketal-polyethylene glycol MN tips, they can be unlocked to release Met directly around the pathogen under the high ROS in the periodontitis sulcus, bringing about improved therapeutic effects. Based on these characteristics, the proposed bioinspired MNs show good therapeutic results in treating a rat model with periodontitis, implying their potential in periodontal disease.

Encoded Structural Color Microneedle Patches for Multiple Screening of Wound Small Molecules.

Detection of biomarkers associated with wound conditions provides in-depth healthcare information and benefits wound healing treatment. The current aim of wound detection is to achieve in situ multiple detections. Novel encoded structural color microneedle patches (EMNs) combining photonic crystals (PhCs) and microneedle arrays (MNs) for multiple wound biomarker detection in situ are described here. Using a partitioned and layered casting strategy, the EMNs can be divided into different modules and each serves for the detection of small molecules , including pH, glucose, and histamine. pH sensing is based on the interaction between hydrogen ions and carboxyl groups from hydrolyzed polyacrylamide (PAM); glucose sensing is achieved with the help of glucose-responsive fluorophenylboronic acid (FPBA); while histamine sensing relies on specific recognition of aptamers and target molecules. Owing to the responsive volume change of these three modules in the presence of target molecules, the EMNs can create structural color change and characteristic peak shift of the PhCs, thus realizing the qualitative measurement of target molecules with a spectrum analyzer. It is further demonstrated that the EMNs behave well in the multivariate detection of rat wound molecules. These features indicate that the EMNs can be valuable smart detection systems for wound status screening.

Optimized prime editing efficiently generates heritable mutations in maize.

Low efficiency is the main obstacle to using prime editing in maize (Zea mays). Recently, prime-editing efficiency was greatly improved in mammalian cells and rice (Oryza sativa) plants by engineering prime-editing guide RNAs (pegRNAs), optimizing the prime editor (PE) protein, and manipulating cellular determinants of prime editing. In this study, we tested PEs optimized via these three strategies in maize. We demonstrated that the ePE5max system, composed of PEmax, epegRNAs (pegRNA-evopreQ. 1), nicking single guide RNAs (sgRNAs), and MLH1dn, efficiently generated heritable mutations that conferred resistance to herbicides that inhibit 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), acetolactate synthase (ALS), or acetyl CoA carboxylase (ACCase) activity. Collectively, we demonstrate that the ePE5max system has sufficient efficiency to generate heritable (homozygous or heterozygous) mutations in maize target genes and that the main obstacle to using PEs in maize has thus been removed.

A teosinte-derived allele of an HKT1 family sodium transporter improves salt tolerance in maize.

The sodium cation (Na+ ) is the predominant cation with deleterious effects on crops in salt-affected agricultural areas. Salt tolerance of crop can be improved by increasing shoot Na+ exclusion. Therefore, it is crucial to identify and use genetic variants of various crops that promote shoot Na+ exclusion. Here, we show that a HKT1 family gene ZmNC3 (Zea mays L. Na+ Content 3; designated ZmHKT1;2) confers natural variability in shoot-Na+ accumulation and salt tolerance in maize. ZmHKT1;2 encodes a Na+ -preferential transporter localized in the plasma membrane, which mediates shoot Na+ exclusion, likely by withdrawing Na+ from the root xylem flow. A naturally occurring nonsynonymous SNP (SNP947-G) increases the Na+ transport activity of ZmHKT1;2, promoting shoot Na+ exclusion and salt tolerance in maize. SNP947-G first occurred in the wild grass teosinte (at a allele frequency of 43%) and has become a minor allele in the maize population (allele frequency 6.1%), suggesting that SNP947-G is derived from teosinte and that the genomic region flanking SNP947 likely has undergone selection during domestication or post-domestication dispersal of maize. Moreover, we demonstrate that introgression of the SNP947-G ZmHKT1;2 allele into elite maize germplasms reduces shoot Na+ content by up to 80% and promotes salt tolerance. Taken together, ZmNC3/ZmHKT1;2 was identified as an important QTL promoting shoot Na+ exclusion, and its favourable allele provides an effective tool for developing salt-tolerant maize varieties.

Differentially Expressed microRNAs in Peritoneal Dialysis Effluent-Derived Exosomes from the Patients with Ultrafiltration Failure.

Background: Ultrafiltration failure remains one of the most severe complications of long-term peritoneal dialysis (PD), which results in death. This study aimed to characterize the circulating exosomal microRNA (miRNA) profiles associated with ultrafiltration failure and explore its underlying mechanisms. Methods: Exosomes were isolated from the peritoneal dialysis effluent (PDE) of patients with ultrafiltration failure or success using the ultracentrifugation method, and then transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot were used for exosome characterization. After that, the isolated exosomes were sent for small RNA sequencing, and eight differentially expressed miRNAs (DE-miRNAs) were chosen for RT-qPCR validation. Results: TEM, NTA, and western blot revealed that exosomes were successfully isolated. After sequencing, 70 DE-miRNAs involved in ultrafiltration were identified, including 41 upregulated ones and 29 downregulated ones. Functional analyses revealed that these DE-miRNAs were significantly enriched in pathways of cancer, ubiquitin-mediated proteolysis, axon orientation, and the Rap1 and Ras signaling pathways. In addition, the consistency rate of RT-qPCR and sequencing results was 75%, which indicated the relatively high reliability of the sequencing data. Conclusions: Our findings implied that these DE-miRNAs may be potential biomarkers of ultrafiltration failure, which would help us to discover novel therapeutic targets/pathways for ultrafiltration failure in patients with end-stage renal disease.

Multifunctional Inverse Opal Microneedle Arrays for Drug Delivery and Monitoring.

Microneedle arrays (MNs) have a demonstrated value in transdermal drug delivery systems. Attempts to this technology focus on the generation of functional MNs to achieve intelligent drug delivery. Here, multifunctional inverse opal microneedle (IOMN) arrays with the abilities are reported to load various drugs and monitor drug release. The IOMNs are generated by using poly(ethylene glycol) diacrylate (PEGDA) to replicate hierarchical structure templates that are composed of self-assembled silica colloidal nanoparticles in the inverted cone structure wells. Because of their interconnected porous structures, different actives, or drugs can be loaded into the IOMNs without organic solvents and chemical polymerization. It is demonstrated that when these drugs loaded IOMNs pierce the skin at position of interest and for slow release, the average refractive index of the IOMNs decreases with the release process, resulting in a corresponding blueshift of their characteristic spectrum. Thus, by measuring the wavelength shift value of the IOMNs, the amount of released drugs can be monitored, providing essential guidance for efficient clinical treatment. These features indicate that the IOMNs are valuable smart drug delivery systems in personalized therapy.

The classical SOS pathway confers natural variation of salt tolerance in maize.

Sodium (Na+ ) is the major cation damaging crops in the salinised farmland. Previous studies have shown that the Salt Overly Sensitive (SOS) pathway is important for salt tolerance in Arabidopsis. Nevertheless, the SOS pathway remains poorly investigated in most crops. This study addresses the function of the SOS pathway and its association with the natural variation of salt tolerance in maize. First, we showed that a naturally occurring 4-bp frame-shifting deletion in ZmSOS1 caused the salt hypersensitive phenotype of the maize inbred line LH65. Accordingly, mutants lacking ZmSOS1 also displayed a salt hypersensitive phenotype, due to an impaired root-to-rhizosphere Na+ efflux and an increased shoot Na+ concentration. We next showed that the maize SOS3/SOS2 complex (ZmCBL4/ZmCIPK24a and ZmCBL8/ZmCIPK24a) phosphorylates ZmSOS1 therefore activating its Na+ -transporting activity, with their loss-of-function mutants displaying salt hypersensitive phenotypes. Moreover, we observed that a LTR/Gypsy insertion decreased the expression of ZmCBL8, thereby increasing shoot Na+ concentration in natural maize population. Taken together, our study demonstrated that the maize SOS pathway confers a conservative salt-tolerant role, and the components of SOS pathway (ZmSOS1 and ZmCBL8) confer the natural variations of Na+ regulation and salt tolerance in maize, therefore providing important gene targets for breeding salt-tolerant maize.

LaCl3 treatment improves Agrobacterium-mediated immature embryo genetic transformation frequency of maize.

KEY MESSAGE: We report an optimized transformation system that uses a LaCl3 pretreatment (a Ca2+ channel blocker) for enhancing Agrobacterium-mediated infection of immature embryos and improving the genetic transformation frequency of maize. Agrobacterium-mediated genetic transformation of immature embryos is important for gene-function studies and molecular breeding of maize. However, the relatively low genetic transformation frequency remains a bottleneck for applicability of this method, especially on commercial scale. We report that pretreatment of immature embryos with LaCl3 (a Ca2+ channel blocker) improves the infection frequency of Agrobacterium tumefaciens, increases the proportion of positive callus, yields more positive regenerated plantlets, and increases the transformation frequency from 8.40 to 17.60% for maize. This optimization is a novel method for improving the frequency of plant genetic transformations mediated by Agrobacterium tumefaciens.

Diet-induced maternal obesity impacts feto-placental growth and induces sex-specific alterations in placental morphology, mitochondrial bioenergetics, dynamics, lipid metabolism and oxidative stress in mice.

AIM: The current study investigated the impact of maternal obesity on placental phenotype in relation to fetal growth and sex. METHODS: Female C57BL6/J mice were fed either a diet high in fat and sugar or a standard chow diet, for 6 weeks prior to, and during, pregnancy. At day 19 of gestation, placental morphology and mitochondrial respiration and dynamics were assessed using high-resolution respirometry, stereology, and molecular analyses. RESULTS: Diet-induced maternal obesity increased the rate of small for gestational age fetuses in both sexes, and increased blood glucose concentrations in offspring. Placental weight, surface area, and maternal blood spaces were decreased in both sexes, with reductions in placental trophoblast volume, oxygen diffusing capacity, and an increased barrier to transfer in males only. Despite these morphological changes, placental mitochondrial respiration was unaffected by maternal obesity, although the influence of fetal sex on placental respiratory capacity varied between dietary groups. Moreover, in males, but not females, maternal obesity increased mitochondrial complexes (II and ATP synthase) and fission protein DRP1 abundance. It also reduced phosphorylated AMPK and capacity for lipid synthesis, while increasing indices of oxidative stress, specifically in males. In females only, placental mitochondrial biogenesis and capacity for lipid synthesis, were both enhanced. The abundance of uncoupling protein-2 was decreased by maternal obesity in both fetal sexes. CONCLUSION: Maternal obesity exerts sex-dependent changes in placental phenotype in association with alterations in fetal growth and substrate supply. These findings may inform the design of personalized lifestyle interventions or therapies for obese pregnant women.

Placental mitochondrial function in response to gestational exposures.

Poor environmental conditions, including malnutrition, hypoxia and obesity in the mother increase the risk of pregnancy complications, such as pre-eclampsia and gestational diabetes mellitus, which impacts the lifelong health of the mother and her offspring. The placenta plays an important role in determining pregnancy outcome by acting as an exchange interface and endocrine hub to support fetal growth. Mitochondria are energy powerhouses of cells that fuel placental physiology throughout pregnancy, including placental development, substrate exchange and hormone secretion. They are responsive to environmental cues and changes in mitochondrial function may serve to mediate or mitigate the impacts of poor gestational environments on placental physiology and hence, the risks of pregnancy complications. Thus, a more integrated understanding about the role of placental mitochondria in orchestrating changes in relation to environmental conditions and pregnancy outcome is paramount. This review summarises the functions of mitochondria in the placenta and findings from humans and experimental animals that demonstrate how mitochondrial structure and function are altered in different gestational environments (namely complicated pregnancies and adverse environmental conditions). Together the available data suggest that mitochondria in the placenta play a major role in determining placental physiology, fetal growth and pregnancy outcome.

Prime editing efficiently generates W542L and S621I double mutations in two ALS genes in maize.

Prime editing is a novel and universal CRISPR/Cas-derived precision genome-editing technology that has been recently developed. However, low efficiency of prime editing has been shown in transgenic rice lines. We hypothesize that enhancing pegRNA expression could improve prime-editing efficiency. In this report, we describe two strategies for enhancing pegRNA expression. We construct a prime editing vector harboring two pegRNA variants for W542L and S621I double mutations in ZmALS1 and ZmALS2. Compared with previous reports in rice, we achieve much higher prime-editing efficiency in maize. Our results are inspiring and provide a direction for the optimization of plant prime editors.

A Novel Ternary Vector System United with Morphogenic Genes Enhances CRISPR/Cas Delivery in Maize.

The lack of efficient delivery methods is a major barrier to clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas)-mediated genome editing in many plant species. Combinations of morphogenic regulator (MR) genes and ternary vector systems are promising solutions to this problem. In this study, we first demonstrated that MR vectors greatly enhance maize (Zea mays) transformation. We then tested a CRISPR/Cas9 MR vector in maize and found that the MR and CRISPR/Cas9 modules have no negative influence on each other. Finally, we developed a novel ternary vector system to integrate the MR and CRISPR/Cas modules. Our ternary vector system is composed of new pGreen-like binary vectors, here named pGreen3, and a pVS1-based virulence helper plasmid, which also functions as a replication helper for the pGreen3 vectors in Agrobacterium tumefaciens The pGreen3 vectors were derived from the plasmid pRK2 and display advantages over pGreen2 vectors regarding both compatibility and stability. We demonstrated that the union of our ternary vector system with MR gene modules has additive effects in enhancing maize transformation and that this enhancement is especially evident in the transformation of recalcitrant maize inbred lines. Collectively, our ternary vector system-based tools provide a user-friendly solution to the low efficiency of CRISPR/Cas delivery in maize and represent a basic platform for developing efficient delivery tools to use in other plant species recalcitrant to transformation.

Overexpression of a PLDα1 gene from Setaria italica enhances the sensitivity of Arabidopsis to abscisic acid and improves its drought tolerance.

Phospholipase D (PLD) plays an important role in various physiological processes in plants, including drought tolerance. Here, we report the cloning and characterization of the full-length cDNA of PLDalpha1 from foxtail millet, which is a cereal crop with high water use efficiency. The expression pattern of the SiPLDalpha1 gene in foxtail millet revealed that it is up-regulated under dehydration, ABA and NaCl treatments. Heterologous overexpression of SiPLDalpha1 in Arabidopsis can significantly enhance their sensitivity to ABA, NaCl and mannitol during post-germination growth. Under water deprivation, overexpression of SiPLDalpha1 in Arabidopsis resulted in significantly enhanced tolerance to drought stress, displaying higher biomass and RWC, lower ion leakage and higher survival percentages than the wild type. Further analysis indicated that transgenic plants showed increased transcription of the stress-related genes, RD29A, RD29B, RAB18 and RD22, and the ABA-related genes, ABI1 and NCED3 under dehydration conditions. These results demonstrate that SiPLDalpha1 is involved in plant stress signal transduction, especially in the ABA signaling pathway. Moreover, no obvious adverse effects on growth and development in the 35S::SiPLDalpha1 transgenic plants implied that SiPLDalpha1 is a good candidate gene for improving crop drought tolerance.