A C4 plant K+ channel accelerates stomata to enhance C3 photosynthesis and water use efficiency.

Accelerating stomatal kinetics through synthetic optogenetics and mutations that enhance guard cell K+ flux has proven a viable strategy to improve water use efficiency and biomass production. Stomata of the model C4 species Gynandropsis gynandra, a relative of the C3 plant Arabidopsis thaliana, are similarly fast to open and close. We identified and cloned the guard cell rectifying outward K+ channel (GROK) of Gynandropsis and showed that GROK is preferentially expressed in stomatal guard cells.

Exaptation of ancestral cell-identity networks enables C photosynthesis.

C photosynthesis is used by the most productive plants on the planet, and compared with the ancestral C pathway, it confers a 50% increase in efficiency. In more than 60 C lineages, CO fixation is compartmentalized between tissues, and bundle-sheath cells become photosynthetically activated. How the bundle sheath acquires this alternate identity that allows efficient photosynthesis is unclear.

Streamlined regulation of chloroplast development in the liverwort Marchantia polymorpha.

Chloroplasts develop from undifferentiated plastids in response to light. In angiosperms, after the perception of light, the Elongated Hypocotyl 5 (HY5) transcription factor initiates photomorphogenesis, and two families of transcription factors known as GOLDEN2-LIKE (GLK) and GATA are considered master regulators of chloroplast development. In addition, the MIR171-targeted SCARECROW-LIKE GRAS transcription factors also impact chlorophyll biosynthesis.

MYB-related transcription factors control chloroplast biogenesis.

Chloroplast biogenesis is dependent on master regulators from the GOLDEN2-LIKE (GLK) family of transcription factors. However, glk mutants contain residual chlorophyll, indicating that other proteins must be involved. Here, we identify MYB-related transcription factors as regulators of chloroplast biogenesis in the liverwort Marchantia polymorpha and angiosperm Arabidopsis thaliana.

Advancing Engineered Plant Living Materials through Tobacco BY-2 Cell Growth and Transfection within Tailored Granular Hydrogel Scaffolds.

In this study, an innovative approach is presented in the field of engineered plant living materials (EPLMs), leveraging a sophisticated interplay between synthetic biology and engineering. We detail a 3D bioprinting technique for the precise spatial patterning and genetic transformation of the tobacco BY-2 cell line within custom-engineered granular hydrogel scaffolds. Our methodology involves the integration of biocompatible hydrogel microparticles (HMPs) primed for 3D bioprinting with capable of plant cell transfection, serving as the backbone for the simultaneous growth and transformation of tobacco BY-2 cells.

Rice bundle sheath cell shape is regulated by the timing of light exposure during leaf development.

Plant leaves contain multiple cell types which achieve distinct characteristics whilst still coordinating development within the leaf. The bundle sheath possesses larger individual cells and lower chloroplast content than the adjacent mesophyll, but how this morphology is achieved remains unknown. To identify regulatory mechanisms determining bundle sheath cell morphology we tested the effects of perturbing environmental (light) and endogenous signals (hormones) during leaf development of Oryza sativa (rice).

Plasmodesmal connectivity in C Gynandropsis gynandra is induced by light and dependent on photosynthesis.

In leaves of C plants, the reactions of photosynthesis become restricted between two compartments. Typically, this allows accumulation of C acids in mesophyll (M) cells and subsequent decarboxylation in the bundle sheath (BS). In C grasses, proliferation of plasmodesmata between these cell types is thought to increase cell-to-cell connectivity to allow efficient metabolite movement.

Neonatal high-frequency oscillatory ventilation: where are we now?

High-frequency oscillatory ventilation (HFOV) is an established mode of respiratory support in the neonatal intensive care unit. Large clinical trial data is based on first intention use in preterm infants with acute respiratory distress syndrome. Clinical practice has evolved from this narrow population.

COVID-19 Excess Deaths in Peru's 25 States in 2020: Nationwide Trends, Confounding Factors, and Correlations With the Extent of Ivermectin Treatment by State.

Introduction In 2020, nations hastened to contain an emerging COVID-19 pandemic by deploying diverse public health approaches, but conclusive appraisals of the efficacy of these approaches are elusive in most cases. One of the medicines deployed, ivermectin (IVM), a macrocyclic lactone having biochemical activity against SARS-CoV-2 through competitive binding to its spike protein, has yielded mixed results in randomized clinical trials (RCTs) for COVID-19 treatments. In Peru, an opportunity to track the efficacy of IVM with a close consideration of confounding factors was provided through data for excess deaths as correlated with IVM use in 2020, under semi-autonomous policies in its 25 states.

Improving photosynthetic efficiency toward food security: Strategies, advances, and perspectives.

Photosynthesis in crops and natural vegetation allows light energy to be converted into chemical energy and thus forms the foundation for almost all terrestrial trophic networks on Earth. The efficiency of photosynthetic energy conversion plays a crucial role in determining the portion of incident solar radiation that can be used to generate plant biomass throughout a growth season. Consequently, alongside the factors such as resource availability, crop management, crop selection, maintenance costs, and intrinsic yield potential, photosynthetic energy use efficiency significantly influences crop yield.

Gene duplications facilitate C4-CAM compatibility in common purslane.

Common purslane (Portulaca oleracea) integrates both C4 and crassulacean acid metabolism (CAM) photosynthesis pathways and is a promising model plant to explore C4-CAM plasticity. Here, we report a high-quality chromosome-level genome of nicotinamide adenine dinucleotide (NAD)-malic enzyme (ME) subtype common purslane that provides evidence for 2 rounds of whole-genome duplication (WGD) with an ancient WGD (P-β) in the common ancestor to Portulacaceae and Cactaceae around 66.30 million years ago (Mya) and another (Po-α) specific to common purslane lineage around 7.

Compartmentation of photosynthesis gene expression in C4 maize depends on time of day.

Compared with the ancestral C3 state, C4 photosynthesis occurs at higher rates with improved water and nitrogen use efficiencies. In both C3 and C4 plants, rates of photosynthesis increase with light intensity and are maximal around midday. We determined that in the absence of light or temperature fluctuations, photosynthesis in maize (Zea mays) peaks in the middle of the subjective photoperiod.

A rapid and robust leaf ablation method to visualize bundle sheath cells and chloroplasts in C and C grasses.

Background: It has been proposed that engineering the C photosynthetic pathway into C crops could significantly increase yield. This goal requires an increase in the chloroplast compartment of bundle sheath cells in C species. To facilitate large-scale testing of candidate regulators of chloroplast development in the rice bundle sheath, a simple and robust method to phenotype this tissue in C species is required.

A rapid method to quantify vein density in C plants using starch staining.

C photosynthesis has evolved multiple times in the angiosperms and typically involves alterations to the biochemistry, cell biology and development of leaves. One common modification found in C plants compared with the ancestral C state is an increase in vein density such that the leaf contains a larger proportion of bundle sheath cells. Recent findings indicate that there may be significant intraspecific variation in traits such as vein density in C plants but to use such natural variation for trait-mapping, rapid phenotyping would be required.

C gene induction during de-etiolation evolved through changes in cis to allow integration with ancestral C gene regulatory networks.

C photosynthesis has evolved by repurposing enzymes found in C plants. Compared with the ancestral C state, accumulation of C cycle proteins is enhanced. We used de-etiolation of C and C to understand this process.

An optimized transformation protocol for Anthoceros agrestis and three more hornwort species.

Land plants comprise two large monophyletic lineages, the vascular plants and the bryophytes, which diverged from their most recent common ancestor approximately 480 million years ago. Of the three lineages of bryophytes, only the mosses and the liverworts are systematically investigated, while the hornworts are understudied. Despite their importance for understanding fundamental questions of land plant evolution, they only recently became amenable to experimental investigation, with Anthoceros agrestis being developed as a hornwort model system.

The Gynandropsis gynandra genome provides insights into whole-genome duplications and the evolution of C4 photosynthesis in Cleomaceae.

Gynandropsis gynandra (Cleomaceae) is a cosmopolitan leafy vegetable and medicinal plant, which has also been used as a model to study C4 photosynthesis due to its evolutionary proximity to C3 Arabidopsis (Arabidopsis thaliana). Here, we present the genome sequence of G. gynandra, anchored onto 17 main pseudomolecules with a total length of 740 Mb, an N50 of 42 Mb and 30,933 well-supported gene models.

Phytochrome B regulates reactive oxygen signaling during abiotic and biotic stress in plants.

Reactive oxygen species (ROS) and the photoreceptor protein phytochrome B (phyB) play a key role in plant acclimation to stress. However, how phyB that primarily functions in the nuclei impacts ROS signaling mediated by respiratory burst oxidase homolog (RBOH) proteins that reside on the plasma membrane, during stress, is unknown. Arabidopsis thaliana and Oryza sativa mutants, RNA-Seq, bioinformatics, biochemistry, molecular biology, and whole-plant ROS imaging were used to address this question.

Photosynthesis: Compatibility between incompatible pathways explained.

A recent study has overturned a long-held view that two distinct modifications to photosynthesis are incompatible. The findings provide interesting new insights into trade-offs associated with photosynthetic metabolism, as well as likely routes by which evolution altered one of the most fundamental processes in biology.

Shedding light on AT1G29480 of -An enigmatic locus restricted to Brassicacean genomes.

A key feature of C Kranz anatomy is the presence of an enlarged, photosynthetically highly active bundle sheath whose cells contain large numbers of chloroplasts. With the aim to identify novel candidate regulators of C bundle sheath development, we performed an activation tagging screen with . The reporter gene used encoded a chloroplast-targeted GFP protein preferentially expressed in the bundle sheath, and the promoter of the C phosphopyruvate carboxylase gene from served as activation tag because of its activity in all chlorenchymatous tissues of .

Regular Use of Ivermectin as Prophylaxis for COVID-19 Led Up to a 92% Reduction in COVID-19 Mortality Rate in a Dose-Response Manner: Results of a Prospective Observational Study of a Strictly Controlled Population of 88,012 Subjects.

Background We have previously demonstrated that ivermectin used as prophylaxis for coronavirus disease 2019 (COVID-19), irrespective of the regularity, in a strictly controlled citywide program in Southern Brazil (Itajaí, Brazil), was associated with reductions in COVID-19 infection, hospitalization, and mortality rates. In this study, our objective was to determine if the regular use of ivermectin impacted the level of protection from COVID-19 and related outcomes, reinforcing the efficacy of ivermectin through the demonstration of a dose-response effect. Methods This exploratory analysis of a prospective observational study involved a program that used ivermectin at a dose of 0.

Abscisic acid modulates neighbor proximity-induced leaf hyponasty in Arabidopsis.

Leaves of shade-avoiding plants such as Arabidopsis (Arabidopsis thaliana) change their growth pattern and position in response to low red to far-red ratios (LRFRs) encountered in dense plant communities. Under LRFR, transcription factors of the phytochrome-interacting factor (PIF) family are derepressed. PIFs induce auxin production, which is required for promoting leaf hyponasty, thereby favoring access to unfiltered sunlight.

A single promoter-TALE system for tissue-specific and tuneable expression of multiple genes in rice.

In biological discovery and engineering research, there is a need to spatially and/or temporally regulate transgene expression. However, the limited availability of promoter sequences that are uniquely active in specific tissue-types and/or at specific times often precludes co-expression of multiple transgenes in precisely controlled developmental contexts. Here, we developed a system for use in rice that comprises synthetic designer transcription activator-like effectors (dTALEs) and cognate synthetic TALE-activated promoters (STAPs).

Correction: Ivermectin Prophylaxis Used for COVID-19: A Citywide, Prospective, Observational Study of 223,128 Subjects Using Propensity Score Matching.

[This corrects the article DOI: 10.7759/cureus.21272.