Cyclin A participates in the TSO1-MYB3R1 regulatory module to maintain shoot meristem size and fertility in Arabidopsis.

The stem cell pools at the shoot apex and root tip give rise to all the above- and below-ground tissues of a plant. Previous studies in Arabidopsis identified a TSO1-MYB3R1 transcriptional module that controls the number and size of the stem cell pools at the shoot apex and root tip. As TSO1 and MYB3R1 are homologous to components of an animal cell cycle regulatory complex, DREAM, Arabidopsis mutants of TSO1 and MYB3R1 provide valuable tools for investigations into the link between cell cycle regulation and stem cell maintenance in plants. In this study, an Arabidopsis cyclin A gene, CYCA3;4, was identified as a member of the TSO1-MYB3R1 regulatory module and cyca3;4 mutations suppressed the tso1-1 mutant phenotype specifically in the shoot. The work reveals how the TSO1-MYB3R1 module is integrated with the cell cycle machinery to control cell division at the shoot meristem.

DaXi-high-resolution, large imaging volume and multi-view single-objective light-sheet microscopy.

The promise of single-objective light-sheet microscopy is to combine the convenience of standard single-objective microscopes with the speed, coverage, resolution and gentleness of light-sheet microscopes. We present DaXi, a single-objective light-sheet microscope design based on oblique plane illumination that achieves: (1) a wider field of view and high-resolution imaging via a custom remote focusing objective; (2) fast volumetric imaging over larger volumes without compromising image quality or necessitating tiled acquisition; (3) fuller image coverage for large samples via multi-view imaging and (4) higher throughput multi-well imaging via remote coverslip placement. Our instrument achieves a resolution of 450 nm laterally and 2 µm axially over an imaging volume of 3,000 × 800 × 300 µm. We demonstrate the speed, field of view, resolution and versatility of our instrument by imaging various systems, including Drosophila egg chamber development, zebrafish whole-brain activity and zebrafish embryonic development - up to nine embryos at a time.

Berberine alleviates contrast-induced nephropathy by activating Akt/Foxo3a/Nrf2 signalling pathway.

Contrast-induced nephropathy (CIN) is a condition that causes kidney damage in patients receiving angiography with iodine-based contrast agents. This study investigated the potential protective effects of berberine (BBR) against CIN and its underlying mechanisms. The researchers conducted both in vivo and in vitro experiments to explore BBR's renal protective effects. In the in vivo experiments, SD rats were used to create a CIN model, and different groups were established. The results showed that CIN model group exhibited impaired renal function, severe damage to renal tubular cells and increased apoptosis and ferroptosis. However, BBR treatment group demonstrated improved renal function, decreased apoptosis and ferroptosis. Similar results were observed in the in vitro experiments using HK-2 cells. BBR reduced ioversol-induced apoptosis and ferroptosis, and exerted its protective effects through Akt/Foxo3a/Nrf2 signalling pathway. BBR administration increased the expression of Foxo3a and Nrf2 while decreasing the levels of p-Akt and p-Foxo3a. In conclusion, this study revealed that BBR effectively inhibited ioversol-induced apoptosis and ferroptosis in vivo and in vitro. The protective effects of BBR were mediated through the modulation of Akt/Foxo3a/Nrf2 signalling pathway, leading to the alleviation of CIN. These findings suggest that BBR may have therapeutic potential for protecting against CIN in patients undergoing angiography with iodine-based contrast agents.

Berberine ameliorates contrast-induced acute kidney injury by regulating HDAC4-FoxO3a axis-induced autophagy: In vivo and in vitro.

In hospitals, contrast-induced acute kidney injury (CI-AKI) is a major cause of renal failure. This study evaluates berberine's (BBR) renal protection and its potential HDAC4 mechanism. CI-AKI in rats was induced with 10 mL kg-1 ioversol. Rats were divided into five groups: Ctrl, BBR, CI-AKI, CI-AKI + BBR, and CI-AKI + Tasq. The renal function of CI-AKI rats was determined by measuring serum creatinine and blood urea nitrogen. Histopathological changes and apoptosis of renal tubular epithelial cells were observed by HE and terminal deoxynucleotidyl transferase (TdTase)-mediated dUTP-biotin nick end labeling (TUNEL) staining. Transmission electron microscopy was used to observe autophagic structures. In vitro, a CI-AKI cell model was created with ioversol-treated HK-2 cells. Treatments included BBR, Rapa, HCQ, and Tasq. Analyses focused on proteins and genes associated with kidney injury, apoptosis, autophagy, and the HDAC4-FoxO3a axis. BBR showed significant protective effects against CI-AKI both in vivo and in vitro. It inhibited apoptosis by increasing Bcl-2 protein levels and decreasing Bax levels. BBR also activated autophagy, as indicated by changes in autophagy-related proteins and autophagic flux. The study further revealed that the contrast agent ioversol increased the expression of HDAC4, which led to elevated levels of phosphorylated FoxO3a (p-FoxO3a) and acetylated FoxO3a (Ac-FoxO3a). However, BBR inhibited HDAC4 expression, resulting in decreased levels of p-FoxO3a and Ac-FoxO3a. This activation of autophagy-related genes, regulated by the transcription factor FoxO3a, played a role in BBR's protective effects. BBR, a traditional Chinese medicine, shows promise against CI-AKI. It may counteract CI-AKI by modulating HDAC4 and FoxO3a, enhancing autophagy, and limiting apoptosis.

The clinical predictive value and regulation mechanism of microRNA-188-5p in contrast-induced acute kidney injury.

Contrast-induced acute kidney injury (CI-AKI), also known as contrast-induced nephropathy (CIN), has become the third leading cause of iatrogenic AKI. Serum creatinine (Scr) is currently used in CIN clinical diagnosis. Patients with increased Scr have developed severe kidney injury, so there is an urgent need to find a bio-marker for CIN early diagnosis. To investigate the changes in circulating microRNA-188-5p (miR-188-5p) after coronary angiography and its predictive value for the CIN occurrence, miR-188-5p expression in CIN rats from the GEO database and CIN patients and control patients from Lianshui People's Hospital was analyzed. The results showed that miR-188-5p expression in plasma and renal was higher in CIN group than in control group. Further, a total of 36 CIN patients and 108 non-CIN patients were included. There were significant differences in age, hypertension, diabetes, and contrast agent dosage. After 12 h of contrast agent application, circulating miR-188-5p expression in CIN group was higher than control group. Univariate and multivariate logistic regression analysis showed that age, hypertension, diabetes, contrast media dosage and postoperative miR-188-5p expression were closely related to CIN occurrence. For in vitro experiments, intracellular miR-188-5p expression was decreased with ioversol treatment, while miR-188-5p expression in supernatant was increased. To explore the potential mechanism of miR-188-5p in CIN, HK-2 cells were treated with NC mimic, ioversol, or miR-188-5p mimic. The results showed that the application of miR-188-5p mimic reduced apoptosis, reactive oxygen species and MDA, enhanced SOD and GSH contents. Further, it was confirmed that mRNA and protein levels of PTEN were up-regulated in ioversol-treated HK-2 cells, and down-regulated after miR-188-5p administration. Dual-luciferase reporter gene assay confirmed that PTEN was direct target gene of miR-188-5p. Above results suggest that circulating miR-188-5p has the potential to serve as a predictor of CIN.

Alcanivorax xiamenensis sp. nov., a novel marine hydrocarbonoclastic bacterium isolated from surface seawater.

A novel Alcanivorax-related strain, designated 6-D-6T, was isolated from the surface seawater collected around Xiamen Island. The novel strain is Gram-stain-negative, rod-shaped and motile, and grows at 10-45 °C, pH 6.0-9.0 and in the presence of 0.5-15.0 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that it belongs to the genus Alcanivorax, with the highest sequence similarity to Alcanivorax dieselolei B5T (99.9 %), followed by Alcanivorax xenomutans JC109T (99.5 %), Alcanivorax balearicus MACL04T (99.3 %) and other 13 species of the genus Alcanivorax (93.8 %-95.6 %). The digital DNA-DNA hybridization and average nucleotide identity values between strain 6-D-6T and three close type strains were 40.1-42.9/90.6-91.4 %, and others were below 22.9/85.1 %, respectively. The novel strain contained major cellular fatty acids of C16 : 0 (31.0 %), C19 : 0 ω8c cyclo (23.5 %), C17 : 0 cyclo (9.7 %), C12 : 0 3OH (8.6 %), summed feature 8 (7.6 %) and C12 : 0 (5.4 %). The genomic G+C content of strain 6-D-6T was 61.38 %. Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified phospholipids and one amino-group-containing phospholipid were detected. On the basis of phenotypic and genotypic characteristics, strain 6-D-6T represents a novel species within the genus Alcanivorax, for which the name Alcanivorax xiamenensis sp. nov. is proposed. The type strain is 6-D-6T (=MCCC 1A01359T=KCTC 92480T).

Paracrocinitomix mangrovi gen. nov., sp. nov., isolated from a mangrove sediment: proposal of two new families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov., and emended description of the family Schleiferiaceae.

A Gram-stain-negative and short rod-shaped bacterial strain designated GM2-3-6-6T was obtained from a mangrove sediment. Cells were light yellow-pigmented, catalase-positive and oxidase-positive. Carotenoid pigment was produced. Phylogeny of the 16S rRNA gene showed that strain GM2-3-6-6T was affiliated to the family Crocinitomicaceae, sharing maximum sequence similarities with Crocinitomix algicola 0182T, C. catalasitica IFO 15977T, and Putridiphycobacter roseus SM1701T of 93.8%, 93.6%, and 92.5%, respectively. The average nucleotide identity values, digital DNA-DNA hybridization estimates and average amino acid identity values between strain GM2-3-6-6T and the three close relatives were 68.6-68.8%, 18.5-19.2%, and 59.0-62.3%, respectively. The complete circular genome of strain GM2-3-6-6T was 4,365,762 bp in length with a DNA G + C content of 35.0%. The respiratory quinone was MK-7. The major polar lipids consisted of phosphatidylethanolamine, two unidentified phospholipids, one unidentified aminoglycolipid, one unidentified aminolipid and four other unidentified lipids. The major fatty acids were iso-C15:0, iso-C15:1 G, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and iso-C17:0 3-OH. Based on genomic, phenotypic, and chemotaxonomic characterizations, strain GM2-3-6-6T represents a novel species of a novel genus, for which the name Paracrocinitomix mangrovi gen. nov., sp. nov. is proposed. The type strain is GM2-3-6-6T (= MCCC 1K04831T = KCTC 82931T). Additionally, phylogenomic analysis of the type strains of the family Schleiferiaceae and family Cryomorphaceae related members including uncultivated bacteria, was performed using the Genome Taxonomic Database toolkit (GTDB-Tk). Based on 16S rRNA gene phylogeny and genomic features, two novel families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov. are proposed. An emended description of the family Schleiferiaceae is also proposed.

SOL1 and SOL2 regulate fate transition and cell divisions in the Arabidopsis stomatal lineage.

In the Arabidopsis stomatal lineage, cells transit through several distinct precursor identities, each characterized by unique cell division behaviors. Flexibility in the duration of these precursor phases enables plants to alter leaf size and stomatal density in response to environmental conditions; however, transitions between phases must be complete and unidirectional to produce functional and correctly patterned stomata. Among direct transcriptional targets of the stomatal initiating factor SPEECHLESS, a pair of genes, SOL1 and SOL2, are required for effective transitions in the lineage. We show that these two genes, which are homologs of the LIN54 DNA-binding components of the mammalian DREAM complex, are expressed in a cell cycle-dependent manner and regulate cell fate and division properties in the self-renewing early lineage. In the terminal division of the stomatal lineage, however, these two proteins appear to act in opposition to their closest paralog, TSO1, revealing complexity in the gene family that may enable customization of cell divisions in coordination with development.

Mitotically heritable epigenetic modifications of CmMYB6 control anthocyanin biosynthesis in chrysanthemum.

Flower color, which is determined by various chemical pigments, is a vital trait for ornamental plants, in which anthocyanin is a major component. However, the epigenetic regulation of anthocyanin biosynthesis remains poorly understood. During chrysanthemum cultivation, we found a heterochromatic chrysanthemum accession (YP) whose progeny generated by asexual reproduction contained both yellow-flowered (YP-Y) and pink-flowered (YP-P) plants. In this study, we aimed to elucidate the epigenetic mechanisms of different flower colors in the YP plant progeny. Metabolome and transcriptome analyses revealed that the difference in flower color between YP-Y and YP-P was caused by expression variation of the anthocyanin biosynthesis gene CmMYB6. Bisulfite sequencing revealed that methylation at the CmMYB6 promoter, especially in the CHH context, was higher in YP-Y than YP-P. After demethylation of the CmMYB6 promoter using the dCas9-TET1cd system, the flower color returned from yellow to pink. Furthermore, the methylation status of the CmMYB6 promoter was higher in YP-Y over three consecutive generations, indicating that this methylation status was heritable mitotically. Finally, investigation of other chrysanthemum cultivars showed that the methylation of CmMYB6 decreased gradually with the increase in anthocyanin content. These results lay an epigenetic foundation for the improvement of flower color in horticultural plants.

Aestuarium zhoushanense is a later heterotypic synonym of Marivivens donghaensis, and transfer of Paradonghicola geojensis to the genus Marivivens as Marivivens geojensis comb. nov.

The 16S rRNA genes of Aestuarium zhoushanense G7T and Paradonghicola geojensis FJ12T shared 100 % sequence identity with Marivivens donghaensis AM-4T. Phylogeny of 16S rRNA gene sequences showed that the three type strains formed a monophyletic clade within the genus Marivivens. Whole genome sequence comparisons showed that three type strains shared 46.7-69.7 % digital DNA-DNA hybridization, 92.1-96.4 % average nucleotide identity and 96.2-98.1 % average amino acid identity. The high 16S rRNA gene similarity values show that three type strains should belong to the same genus. The pan-genome of the five strains contained 5754 genes including 1877 core genes. Based on the principle of priority, we propose that A. zhoushanense Yu et al. 2019 is a later heterotypic synonym of M. donghaensis Park et al. 2016, and P. geojensis should be reclassified as Marivivens geojensis comb. nov., respectively.

Pelagibacterium xiamenense sp. nov., isolated from intertidal sediment.

A Gram-stain-negative, obligately aerobic bacterium, designated as HS1C4-1T, was isolated from a sediment sample from the tidal zone of the Haicang Coast, Xiamen, Fujian Province, PR China. The strain was yellowish-coloured, non-gliding, rod-shaped and motile, with a single polar flagellum. Cells of HS1C4-1T were oxidase- and catalase-positive. The strain could grow at 15-55 °C (optimum 37 °C), pH 6.0-10.0 (optimum, pH 7.0-9.0), in the presence of 0-12 % (optimum, 1 %) NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that HS1C4-1T represented a member of the genus Pelagibacterium, and shared the highest similarity to Pelagibacterium luteolum CGMCC 1.10267T (97.6 %). Digital DNA-DNA hybridization values and average nucleotide identity between HS1C4-1T and all the species of genus Pelagibacterium were 18.7-20.2 % and 77.3-78.4 %, respectively. The principal fatty acids (>10 %) were C19 : 0 cyclo ω8c (50.5 %) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 29.1%). Q-10 was the sole respiratory quinone. The polar lipids included diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and six unidentified lipids. The G+C content of the chromosomal DNA was 62.9 %. On the basis of phylogenetic, phenotypic, chemotaxonomic and genomic characteristics, HS1C4-1T represents a novel species within the genus Pelagibacterium, for which the name Pelagibacterium xiamenense sp. nov. is proposed. The type strain is HS1C4-1T (=MCCC 1A18759T=KCTC 92097T).

A novel contrast-induced acute kidney injury mouse model based on low-osmolar contrast medium.

The contrast-induced acute kidney injury (CI-AKI) has been becoming the third common cause of hospital-acquired acute kidney injury. An ideal animal model is essential for understanding the pathophysiology of CI-AKI. Previous CI-AKI studies were mostly performed on rats with high-osmolar contrast medium (HOCM), which is unsuitable for transgenic researches. This study provides a novel, efficient and reproducible CI-AKI model which was developed in mouse by administrating a low-osmolar contrast medium (LOCM). First of all, we applied the frequently used pretreatments (uninephrectomy and water deprivation), which combined with HOCM on rats could induce CI-AKI, on mice with LOCM. Secondly, we attempted to find a novel pretreatment suitable for mouse and LOCM by combining two classic pretreatments(uninephrectomy, water deprivation and furosemide administration). Finally, we evaluate the kidney damage of the novel model. We found that this mouse model possessed a significant reduction in renal function, severe renal tissue damage, and increased renal tubular cells apoptosis, indicating that LOCM is a feasible inducer for CI-AKI mice model. Taken together, we found that uninephrectomy (UPHT) combined with 24 h water deprivation and furosemide administration 20 min before LOCM (iohexol, 10 ml/kg) application is a feasible pretreatment to establish a novel CI-AKI mouse model.

CRISPR/Cas9-Mediated Multiple Knockouts in Abscisic Acid Receptor Genes Reduced the Sensitivity to ABA during Soybean Seed Germination.

Abscisic acid (ABA) is an important plant hormone that regulates numerous functions in plant growth, development, and stress responses. Several proteins regulate the ABA signal transduction mechanism in response to environmental stress. Among them, the PYR1/PYL/RCAR family act as ABA receptors. This study used the CRISPR/Cas9 gene-editing system with a single gRNA to knock out three soybean PYL genes: GmPYL17, GmPYL18, and GmPYL19. The gRNA may efficiently cause varying degrees of deletion of GmPYL17, GmPYL18, and GmPYL19 gene target sequences, according to the genotyping results of T0 plants. A subset of induced alleles was successfully transferred to progeny. In the T2 generation, we obtained double and triple mutant genotypes. At the seed germination stage, CRISPR/Cas9-created GmPYL gene knockout mutants, particularly gmpyl17/19 double mutants, are less susceptible to ABA than the wild type. RNA-Seq was used to investigate the differentially expressed genes related to the ABA response from germinated seedlings under diverse treatments using three biological replicates. The gmpyl17/19-1 double mutant was less susceptible to ABA during seed germination, and mutant plant height and branch number were higher than the wild type. Under ABA stress, the GO enrichment analysis showed that certain positive germination regulators were activated, which reduced ABA sensitivity and enhanced seed germination. This research gives a theoretical basis for a better understanding of the ABA signaling pathway and the participation of the key component at their molecular level, which helps enhance soybean abiotic stress tolerance. Furthermore, this research will aid breeders in regulating and improving soybean production and quality under various stress conditions.

High-Resolution Small RNAs Landscape Provides Insights into Alkane Adaptation in the Marine Alkane-Degrader Alcanivorax dieselolei B-5

Alkanes are widespread in the ocean, and Alcanivorax is one of the most ubiquitous alkane-degrading bacteria in the marine ecosystem. Small RNAs (sRNAs) are usually at the heart of regulatory pathways, but sRNA-mediated alkane metabolic adaptability still remains largely unknown due to the difficulties of identification. Here, differential RNA sequencing (dRNA-seq) modified with a size selection (~50-nt to 500-nt) strategy was used to generate high-resolution sRNAs profiling in the model species Alcanivorax dieselolei B-5 under alkane (n-hexadecane) and non-alkane (acetate) conditions. As a result, we identified 549 sRNA candidates at single-nucleotide resolution of 5'-ends, 63.4% of which are with transcription start sites (TSSs), and 36.6% of which are with processing sites (PSSs) at the 5'-ends. These sRNAs originate from almost any location in the genome, regardless of intragenic (65.8%), antisense (20.6%) and intergenic (6.2%) regions, and RNase E may function in the maturation of sRNAs. Most sRNAs locally distribute across the 15 reference genomes of Alcanivorax, and only 7.5% of sRNAs are broadly conserved in this genus. Expression responses to the alkane of several core conserved sRNAs, including 6S RNA, M1 RNA and tmRNA, indicate that they may participate in alkane metabolisms and result in more actively global transcription, RNA processing and stresses mitigation. Two novel CsrA-related sRNAs are identified, which may be involved in the translational activation of alkane metabolism-related genes by sequestering the global repressor CsrA. The relationships of sRNAs with the characterized genes of alkane sensing (ompS), chemotaxis (mcp, cheR, cheW2), transporting (ompT1, ompT2, ompT3) and hydroxylation (alkB1, alkB2, almA) were created based on the genome-wide predicted sRNA-mRNA interactions. Overall, the sRNA landscape lays the ground for uncovering cryptic regulations in critical marine bacterium, among which both the core and species-specific sRNAs are implicated in the alkane adaptive metabolisms.

Loss of chromatin remodeler DDM1 causes segregation distortion in Arabidopsis thaliana.

MAIN CONCLUSION: In ddm1 mutants, the DNA methylation is primarily affected in the heterochromatic region of the chromosomes, which is associated with the segregation distortion of SNPs in the F2 progenies. Segregation distortion (SD) is common in most genetic mapping experiments and a valuable resource to determine how gene loci induce deviation. Meiotic DNA crossing over and SD are under the control of several types of epigenetic modifications. DNA methylation is an important regulatory epigenetic modification that is inherited across generations. In the present study, we investigated the relationship between SD and DNA methylation. The ecotypes Col-0/C24 and chromatin remodeler mutants ddm1-10/Col and ddm1-15/C24 were reciprocally crossed to obtain F2 generations. A total of 300 plants for each reciprocally crossed plant in the F2 generations were subjected to next-generation sequencing to detect the single-nucleotide polymorphisms (SNPs) as DNA markers. All SNPs were analyzed using the Chi-square test method to determine their segregation ratio in F2 generations. Through the segregation ratio, whole-genome SNPs were classified into 16 classes. In class 10, the SNPs in the reciprocal crosses of wild type showed the expected Mendelian ratio of 1:2:1, while those in the reciprocal crosses of ddm1 mutants showed distortion. In contrast, all SNPs in class 16 displayed a normal 1:2:1 ratio, and class 1 showed SD, regardless of wild type or mutants, as assessed using CAPS (cleaved amplified polymorphic sequences) marker analysis to confirm the next-generation sequencing. In ddm1 mutants, the DNA methylation is highly reduced throughout the whole genome and more significantly in the heterochromatic regions of chromosomes. Our results showed that the ddm1 mutants exhibit low levels of DNA methylation, which facilitates the SD of SNPs primarily located in the heterochromatic region of chromosomes by reducing the heterozygous ratio. The present study will provide a strong base for future research focusing on the impact of DNA methylation on trait segregation and plant evolution.

Arabidopsis TSO1 and MYB3R1 form a regulatory module to coordinate cell proliferation with differentiation in shoot and root.

Fundamental to plant and animal development is the regulated balance between cell proliferation and differentiation, a process intimately tied to cell cycle regulation. In Arabidopsis, mutations in TSO1, whose animal homolog is LIN54, resulted in severe developmental abnormalities both in shoot and root, including shoot meristem fasciation and reduced root meristematic zone. The molecular mechanism that could explain the tso1 mutant phenotype is absent. Through a genetic screen, we identified 32 suppressors that map to the MYB3R1 gene, encoding a conserved cell cycle regulator. Further analysis indicates that TSO1 transcriptionally represses MYB3R1, and the ectopic MYB3R1 activity mediates the tso1 mutant phenotype. Since animal homologs of TSO1 and MYB3R1 are components of a cell cycle regulatory complex, the DREAM complex, we tested and showed that TSO1 and MYB3R1 coimmunoprecipitated in tobacco leaf cells. Our work reveals a conserved cell cycle regulatory module, consisting of TSO1 and MYB3R1, for proper plant development.

Loss of a highly conserved sterile alpha motif domain gene (WEEP) results in pendulous branch growth in peach trees.

Plant shoots typically grow upward in opposition to the pull of gravity. However, exceptions exist throughout the plant kingdom. Most conspicuous are trees with weeping or pendulous branches. While such trees have long been cultivated and appreciated for their ornamental value, the molecular basis behind the weeping habit is not known. Here, we characterized a weeping tree phenotype in Prunus persica (peach) and identified the underlying genetic mutation using a genomic sequencing approach. Weeping peach tree shoots exhibited a downward elliptical growth pattern and did not exhibit an upward bending in response to 90° reorientation. The causative allele was found to be an uncharacterized gene, Ppa013325, having a 1.8-Kb deletion spanning the 5' end. This gene, dubbed WEEP, was predominantly expressed in phloem tissues and encodes a highly conserved 129-amino acid protein containing a sterile alpha motif (SAM) domain. Silencing WEEP in the related tree species Prunus domestica (plum) resulted in more outward, downward, and wandering shoot orientations compared to standard trees, supporting a role for WEEP in directing lateral shoot growth in trees. This previously unknown regulator of branch orientation, which may also be a regulator of gravity perception or response, provides insights into our understanding of how tree branches grow in opposition to gravity and could serve as a critical target for manipulating tree architecture for improved tree shape in agricultural and horticulture applications.

Role of epigenetic modifications in the development of crops essential traits.

Epigenetic modification refers to the chemical modifications of chromosomal DNA and histones, mainly including DNA methylation, histone modifications and non-coding RNAs. Without altering the DNA sequence, these heritable modifications can affect gene expression profiles by changing the chromatin state and play an important role in regulating the growth and development of plants. When the specific epigenetic modifications are changed, crops can obtain excellent phenotypes and stronger environmental adaptability. Therefore, artificially changing the epigenetic modifications are expected to obtain high-quality germplasm resources more suitable for agricultural production. In this review, we summarize the main types of plant epigenetic modifications, highlight the research progresses of functional plant epigenetic modifications on the important traits and responses to environmental stress, and identify the main problems that need be solved in the application of epigenetics in crop improvement, thereby providing new insights for the functional epigenetic modifications on crop breeding and improvement.

A MFS-like plasma membrane transporter required for Leishmania virulence protects the parasites from iron toxicity.

Iron is essential for many cellular processes, but can generate highly toxic hydroxyl radicals in the presence of oxygen. Therefore, intracellular iron accumulation must be tightly regulated, by balancing uptake with storage or export. Iron uptake in Leishmania is mediated by the coordinated action of two plasma membrane proteins, the ferric iron reductase LFR1 and the ferrous iron transporter LIT1. However, how these parasites regulate their cytosolic iron concentration to prevent toxicity remains unknown. Here we characterize Leishmania Iron Regulator 1 (LIR1), an iron responsive protein with similarity to membrane transporters of the major facilitator superfamily (MFS) and plant nodulin-like proteins. LIR1 localizes on the plasma membrane of L. amazonensis promastigotes and intracellular amastigotes. After heterologous expression in Arabidopsis thaliana, LIR1 decreases the iron content of leaves and worsens the chlorotic phenotype of plants lacking the iron importer IRT1. Consistent with a role in iron efflux, LIR1 deficiency does not affect iron uptake by L. amazonensis but significantly increases the amount of iron retained intracellularly in the parasites. LIR1 null parasites are more sensitive to iron toxicity and have drastically impaired infectivity, phenotypes that are reversed by LIR1 complementation. We conclude that LIR1 functions as a plasma membrane iron exporter with a critical role in maintaining iron homeostasis and promoting infectivity in L. amazonensis.

Visible-Light-Promoted C2 Selective Arylation of Quinoline and Pyridine N-Oxides with Diaryliodonium Tetrafluoroborate.

A protocol of visible-light-promoted C2 selective arylation of quinoline and pyridine N-oxides, with diaryliodonium tetrafluoroborate as an arylation reagent, using eosin Y as a photocatalyst for the construction of N-heterobiaryls was presented. This methodology provided an efficient way for the synthesis of 2-aryl-substituted quinoline and pyridine N-oxides. This strategy has the following advantages: specific regioselectivity, simple operation, good functional group tolerance, and high to moderate yields under mild conditions.