RACK1A promotes hypocotyl elongation by scaffolding light signaling components in Arabidopsis.

Plants deploy versatile scaffold proteins to intricately modulate complex cell signaling. Among these, RACK1A (Receptors for Activated C Kinase 1A) stands out as a multifaceted scaffold protein functioning as a central integrative hub for diverse signaling pathways. However, the precise mechanisms by which RACK1A orchestrates signal transduction to optimize seedling development remain largely unclear. Here, we demonstrate that RACK1A facilitates hypocotyl elongation by functioning as a flexible platform that connects multiple key components of light signaling pathways. RACK1A interacts with PHYTOCHROME INTERACTING FACTOR (PIF)3, enhances PIF3 binding to the promoter of BBX11 and down-regulates its transcription. Furthermore, RACK1A associates with ELONGATED HYPOCOTYL 5 (HY5) to repress HY5 biochemical activity toward target genes, ultimately contributing to hypocotyl elongation. In darkness, RACK1A is targeted by CONSTITUTIVELY PHOTOMORPHOGENIC (COP)1 upon phosphorylation and subjected to COP1-mediated degradation via the 26 S proteasome system. Our findings provide new insights into how plants utilize scaffold proteins to regulate hypocotyl elongation, ensuring proper skoto- and photo-morphogenic development.

Counteraction of ABI5-mediated inhibition of seed germination and postgerminative growth by RACK1 in Arabidopsis.

ABSCISIC ACID (ABA) INSENSITIVE5 (ABI5), the key regulator of abscisic acid (ABA) signaling pathway, plays a fundamental role in seed germination and postgerminative development. However, the detailed molecular mechanism underlying the repression function of ABI5 in these processes remains to be elucidated. In this study, we demonstrate that the conserved eukaryotic WD40 repeat protein RACK1 is a novel negative regulator of ABI5 in Arabidopsis. The RACK1 loss-of-function mutant is hypersensitive to ABA, while this phenotype was rescued by the mutation of ABI5. Moreover, overexpression of RACK1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes. RACK1 could also physically interact with ABI5 and facilitate its degradation. Furthermore, we found that RACK1 and the two substrate receptors for CUL4-based E3 ligases (DWA1 and DWA2) function together to mediate the turnover of ABI5, thereby efficiently turning down ABA signaling for seed germination and postgerminative growth. On the other hand, a series of molecular analyses demonstrated that ABI5 could bind with the promoter of RACK1 to repress its expression. Collectively, our findings suggest that RACK1 and ABI5 might form a feedback loop to regulate the homeostasis of ABA signaling for acute seed germination and early plant development.

Endomembrane-biased dimerization of ABCG16 and ABCG25 transporters determines their substrate selectivity in ABA-regulated plant growth and stress responses.

ATP-binding cassette (ABC) transporters are integral membrane proteins that have evolved diverse functions fulfilled via the transport of various substrates. In Arabidopsis, the G subfamily of ABC proteins is particularly abundant and participates in multiple signaling pathways during plant development and stress responses. In this study, we revealed that two Arabidopsis ABCG transporters, ABCG16 and ABCG25, engage in ABA-mediated stress responses and early plant growth through endomembrane-specific dimerization-coupled transport of ABA and ABA-glucosyl ester (ABA-GE), respectively. We first revealed that ABCG16 contributes to osmotic stress tolerance via ABA signaling. More specifically, ABCG16 induces cellular ABA efflux in both yeast and plant cells. Using FRET analysis, we showed that ABCG16 forms obligatory homodimers for ABA export activity and that the plasma membrane-resident ABCG16 homodimers specifically respond to ABA, undergoing notable conformational changes. Furthermore, we demonstrated that ABCG16 heterodimerizes with ABCG25 at the endoplasmic reticulum (ER) membrane and facilitates the ER entry of ABA-GE in both Arabidopsis and tobacco cells. The specific responsiveness of the ABCG16-ABCG25 heterodimer to ABA-GE and the superior growth of their double mutant support an inhibitory role of these two ABCGs in early seedling establishment via regulation of ABA-GE translocation across the ER membrane. Our endomembrane-specific analysis of the FRET signals derived from the homo- or heterodimerized ABCG complexes allowed us to link endomembrane-biased dimerization to the translocation of distinct substrates by ABCG transporters, providing a prototypic framework for understanding the omnipotence of ABCG transporters in plant development and stress responses.

Characterization of the Disinfectant Resistance Genes qacEΔ1 and cepA in Carbapenem-Resistant Klebsiella pneumoniae Isolates.

The emergence and wide global spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates are of great concern. This multicenter study aimed to investigate the molecular characteristics of CRKP isolates from inpatients in Wuhan, China. From June 2018 to March 2019, 74 nonduplicated CRKP clinical isolates were collected from six hospitals in Wuhan. We determined the minimum inhibitory concentrations of 18 antibiotics and used real-time polymerase chain reaction to detect the presence of disinfectant resistance genes qacEΔ1 and cepA. Pulsed-field gel electrophoresis was conducted to assess the genetic relatedness of isolates. Among the 74 CRKP isolates, the rates of resistance to carbapenems were high: 93.2% to ertapenem, 90.5% to imipenem, and 87.8% to meropenem. All isolates were resistant to at least one carbapenem antibiotic. Of the 74 isolates, 64.9% (48/74) were positive for qacEΔ1 and 93.2% (69/74) for cepA. QacEΔ1 and cepA were detected concomitantly in 46 isolates (62.2%), whereas only 4.1% (3/74) had no disinfectant resistance genes. Pulsed-field gel electrophoresis analysis clustered the 46 CRKP strains co-producing qacEΔ1 and cepA into 15 different clonal clusters (Types A to O). The most common clonal clusters were Type C (41.3%), Type E (13.0%), and Type J (8.7%). The study showed high rates of resistance to most antibiotics and high frequency of qacEΔ1 and cepA in CRKP isolates. Specific clonal dissemination of CRKP was detected within the same hospital or between different hospitals. Therefore, medical institutions should choose and use disinfectants correctly to prevent the spread of CRKP.

Structural insights into AtABCG25, an angiosperm-specific abscisic acid exporter.

Cellular hormone homeostasis is essential for precise spatial and temporal signaling responses and plant fitness. Abscisic acid (ABA) plays pivotal roles in orchestrating various developmental and stress responses and confers fitness benefits over ecological and evolutionary timescales in terrestrial plants. Cellular ABA level is regulated by complex processes, including biosynthesis, catabolism, and transport. AtABCG25 is the first ABA exporter identified through genetic screening and affects diverse ABA responses. Resolving the structural basis of ABA export by ABCG25 is critical for further manipulations of ABA homeostasis and plant fitness. We used cryo-electron microscopy to elucidate the structural dynamics of AtABCG25 and successfully characterized different states, including apo AtABCG25, ABA-bound AtABCG25, and ATP-bound AtABCG25 (E232Q). Notably, AtABCG25 forms a homodimer that features a deep, slit-like cavity in the transmembrane domain, and we precisely characterized the critical residues in the cavity where ABA binds. ATP binding triggers closure of the nucleotide-binding domains and conformational transitions in the transmembrane domains. We show that AtABCG25 belongs to a conserved ABCG subfamily that originated during the evolution of angiosperms. This subfamily neofunctionalized to regulate seed germination via the endosperm, in concert with the evolution of this angiosperm-specific, embryo-nourishing tissue. Collectively, these findings provide valuable insights into the intricate substrate recognition and transport mechanisms of the ABA exporter AtABCG25, paving the way for genetic manipulation of ABA homeostasis and plant fitness.

Nuclear Localization of G3BP6 Is Essential for the Flowering Transition in Arabidopsis.

The Ras GTPase-activating protein SH3 domain-binding protein (G3BP) belongs to the highly conserved family of RNA-binding proteins, which has been well-investigated in humans and animals. However, limited study of plant G3BP has been reported, and the precise biological function of the G3BP family has not been elucidated yet. In this study, the Arabidopsis G3BP family, comprising seven members, was comparatively analyzed. Transcriptome analysis showed that most G3BP genes are ubiquitously expressed in various tissues/organs. Transient expression analysis revealed that all G3BPs were presented in the cytoplasm, among which G3BP6 was additionally found in the nucleus. Further study revealed a conserved NLS motif required for the nuclear localization of G3BP6. Additionally, phenotypic analysis revealed that loss-of-function g3bp6 presented late-flowering phenotypes. RNA-sequencing analysis and qRT-PCR assays demonstrated that the expressions of abundant floral genes were significantly altered in g3bp6 plants. We also discovered that overexpression of G3BP6 in the nucleus, rather than in the cytoplasm, propelled bolting. Furthermore, we revealed that the scaffold protein Receptor for Activated C Kinase 1 (RACK1) interacted with and modulated the nuclear localization of G3BP6. Altogether, this study sheds new light on G3BP6 and its specific role in regulating the flowering transition in Arabidopsis.

Rapid, sensitive, and highly specific detection of monkeypox virus by CRISPR-based diagnostic platform.

Background: Monkeypox (MPX), caused by the Monkeypox virus (MPXV), has incurred global attention since it broke out in many countries in recent times, which highlights the need for rapid and reliable diagnosis of MPXV infection. Methods: We combined recombinase polymerase amplification (RPA) with CRISPR/Cas12a-based detection to devise a diagnostic test for detection of MPXV and differentiation of its two clades [Central Africa clade (MPXV-CA) and West Africa clade (MPXV-WA)], and called it MPXV-RCC. The sensitivity, specificity and practicability of this method have been analyzed. Results: The optimal conditions of MPXV-RCC assay include two RPA reactions at 38°C for 25 min and a CRISPR/Cas12a-gRNA detection at 37°C for 10 min. The results of MPXV-RCC assay were indicated by a real-time fluorescence analysis software. Thus, the whole detection process, including rapid template preparation (20 min), RPA reaction (25 min) and CRISPR-based detection (10 min), could be finished within 1 hour. The sensitivity of MPXV-RCC for MPXV-CA and MPXV-WA detection was down to 5~10 copies of recombination plasmids and pseudovirus per reaction. Particularly, MPXV-RCC assay could clearly differentiate MPXV-CA from MPXV-WA, and had no cross-reactivity with other pathogens. In addition, the feasibility of MPXV-RCC assay was further validated by using spiked clinical samples. Conclusion: The MPXV-RCC assay developed here is a promising tool for quick and reliable diagnosis of MPXV infection.

Scaffold protein RACK1 regulates BR signaling by modulating the nuclear localization of BZR1.

Brassinosteroids (BRs) are a group of plant-specific steroid hormones, which induces the rapid nuclear localization of the positive transcriptional factors BRASSINAZOLE RESISTANT1/2 (BZR1/2). However, the mechanisms underlying the regulation of nucleocytoplasmic shuttling of BZR1 remain to be fully elucidated. In this study, we show that the scaffold protein Receptor for Activated C Kinase 1 (RACK1) from Arabidopsis is involved in BR signaling cascades through mediating the nuclear localization of BZR1, which is tightly retained in the cytosol by the conserved scaffold protein 14-3-3s. RACK1 can interact with BZR1 and competitively decrease the 14-3-3 interaction with BZR1 in cytosol, which efficiently enhances the nuclear localization of BZR1. 14-3-3 also retains RACK1 in cytosol through their interaction. Conversely, BR treatment enhances the nuclear localization of BZR1 by disrupting the 14-3-3 interaction with RACK1 and BZR1. Our study uncovers a new mechanism that integrates two kinds of conserved scaffold proteins (RACK1 and 14-3-3) coordinating BR signaling event.

Scaffold protein RACK1A positively regulates leaf senescence by coordinating the EIN3-miR164-ORE1 transcriptional cascade in Arabidopsis.

Plants have adopted versatile scaffold proteins to facilitate the crosstalk between multiple signaling pathways. Leaf senescence is a well-programmed developmental stage that is coordinated by various external and internal signals. However, the functions of plant scaffold proteins in response to senescence signals are not well understood. Here, we report that the scaffold protein RACK1A (RECEPTOR FOR ACTIVATED C KINASE 1A) participates in leaf senescence mediated by ethylene signaling via the coordination of the EIN3-miR164-ORE1 transcriptional regulatory cascade. RACK1A is a novel positive regulator of ethylene-mediated leaf senescence. The rack1a mutant exhibits delayed leaf senescence, while transgenic lines overexpressing RACK1A display early leaf senescence. Moreover, RACK1A promotes EIN3 (ETHYLENE INSENSITIVE 3) protein accumulation, and directly interacts with EIN3 to enhance its DNA-binding activity. Together, they then associate with the miR164 promoter to inhibit its transcription, leading to the release of the inhibition on downstream ORE1 (ORESARA 1) transcription and the promotion of leaf senescence. This study reveals a mechanistic framework by which RACK1A promotes leaf senescence via the EIN3-miR164-ORE1 transcriptional cascade, and provides a paradigm for how scaffold proteins finely tune phytohormone signaling to control plant development.

[Antibiotic-resistant bacteria contamination in the air of different departments in hospital].

OBJECTIVE: To investigate the contamination of antibiotic-resistant bacteria in air of different departments in hospital. METHODS: From 2018.07 to 2021.06, 191 samples of the air-conditioning filter dust in three hospitals were collected. Antibiotic-resistant bacteria were isolated from the accumulated dust. The drug sensitivity test was conducted for Staphylococcus aureus, Acinetobacter baumannii and Enterobacteriaceae. RESULTS: A total of 119 samples were detected antibiotic-resistant bacteria from 191 samples, and the detection rate was 62.30%. The detection rate of different departments from high to low was surgical ward(68.29%) >intensive care unit(ICU)(59.62%) >medical ward(57.92%). A total of 362 strains of antimicribial-resistant organisms were isolated, mainly were Acinetobacter(28.73%), Pseudomonas(22.10%), Bacillus(22.10%), Staphylococcus(9.12%), etc. Among them, 72 strains of target organisms were detected, and the detection rate was 19.89%(72/362), the detection rate of different target bacteria from high to low was Acinetobacter baumannii(12.71%)>Enterobacteriaceae(4.72%)>Staphylococcus aureus(2.76%)(P<0.05). The drug sensitivity test showed that 41 strains of antimicribial-resistant organisms were detected, and the detection rate was 56.94%(41/72), including carbapenem-resistant Acinetobacter baumannii(CR-ABA), methicillin-resistant Staphylococcus aureus(MRSA), carbapenem-resistant Enterobacteriaceae(CRE), etc.24 strains of multidrug-resistant organisms(MDROs) were detected and the detection rate was 58.54%(24/41). The detection rate of different departments from high to low was ICU(80.00%)>medical ward(60.00%)>surgical ward(46.15%). CONCLUSION: There was contaminated by Acinetobacter baumannii, Staphylococcus aureus, Enterobacteriaceae in the air of hospitals, some of them were MDROs, mainly were detected in neurological ward, respiratory medical ward, hyroid and breast surgery ward, neurosurgery ward, cardiothoracic surgery ward, gallideulous surgical ICU and general ICU.

Highly Sensitive and Specific Detection of Mobilized Colistin Resistance Gene mcr-1 by CRISPR-Based Platform.

Mobilized colistin resistance (mcr-1) gene mediated by plasmid can cause the speediness dissemination of colistin-resistant strains, which have given rise to a great threat to the treatment of human infection. Hence, a rapid and accurate diagnosis technology for detecting mcr-1 is essential for the control of resistance gene. Here, a recombinase polymerase amplification (RPA) coupled with CRISPR/Cas12a platform was established for rapid, sensitive, and specific detection of mcr-1 gene. The analytical sensitivity of our assay is 420 fg per reaction in pure mcr-1-positive isolates, and the threshold of this method in spiked clinical samples was down to 1.6 × 103 ~ 6.2 × 103 CFU/mL (1.6 ~ 6.2 CFU/reaction). Moreover, the RPA-CRISPR/Cas12a system perspicuously demonstrated no cross-reactivity with other resistant genes. The entire experimental process included rapid DNA extraction (15 min), RPA reaction (30 min), CRISPR/Cas12a cleavage (5 min), and fluorescence testing (<10 min), which could be completed within 60 min. In summary, the RPA-CRISPR/Cas12a assay designed here provides a rapid diagnostic way for monitoring mcr-1 in clinic and livestock farm. IMPORTANCE This study promises a rapid and accurate assay (RPA-CRISPR/Cas12a) for the surveillance of mcr-1 gene, which causes the efficacy loss of colistin in clinical treatments. In addition, the established method is fit for "on-site" surveillance especially.

Characterization of Organellar-Specific ABA Responses during Environmental Stresses in Tobacco Cells and Arabidopsis Plants.

Abscisic acid (ABA) is a critical phytohormone involved in multifaceted processes in plant metabolism and growth under both stressed and nonstressed conditions. Its accumulation in various tissues and cells has long been established as a biomarker for plant stress responses. To date, a comprehensive understanding of ABA distribution and dynamics at subcellular resolution in response to environmental cues is still lacking. Here, we modified the previously developed ABA sensor ABAleon2.1_Tao3 (Tao3) and targeted it to different organelles including the endoplasmic reticulum (ER), chloroplast/plastid, and nucleus through the addition of corresponding signal peptides. Together with the cytosolic Tao3, we show distinct ABA distribution patterns in different tobacco cells with the chloroplast showing a lower level of ABA in both cell types. In a tobacco mesophyll cell, organellar ABA displayed specific alterations depending on osmotic stimulus, with ABA levels being generally enhanced under a lower and higher concentration of salt and mannitol treatment, respectively. In Arabidopsis roots, cells from both the meristem and elongation zone accumulated ABA considerably in the cytoplasm upon mannitol treatment, while the plastid and nuclear ABA was generally reduced dependent upon specific cell types. In Arabidopsis leaf tissue, subcellular ABA seemed to be less responsive when stressed, with notable increases of ER ABA in epidermal cells and a reduction of nuclear ABA in guard cells. Together, our results present a detailed characterization of stimulus-dependent cell type-specific organellar ABA responses in tobacco and Arabidopsis plants, supporting a highly coordinated regulatory network for mediating subcellular ABA homeostasis during plant adaptation processes.

Overexpression of Cinnamoyl-CoA Reductase 2 in Brassica napus Increases Resistance to Sclerotinia sclerotiorum by Affecting Lignin Biosynthesis.

Sclerotinia sclerotiorum causes severe yield and economic losses for many crop and vegetable species, especially Brassica napus. To date, no immune B. napus germplasm has been identified, giving rise to a major challenge in the breeding of Sclerotinia resistance. In the present study, we found that, compared with a Sclerotinia-susceptible line (J902), a Sclerotinia-resistant line (J964) exhibited better xylem development and a higher lignin content in the stems, which may limit the invasion and spread of S. sclerotiorum during the early infection period. In addition, genes involved in lignin biosynthesis were induced under S. sclerotiorum infection in both lines, indicating that lignin was deposited proactively in infected tissues. We then overexpressed BnaC.CCR2.b, which encodes the first rate-limiting enzyme (cinnamoyl-CoA reductase) that catalyzes the reaction of lignin-specific pathways, and found that overexpression of BnaC.CCR2.b increased the lignin content in the stems of B. napus by 2.28-2.76% under normal growth conditions. We further evaluated the Sclerotinia resistance of BnaC.CCR2.b overexpression lines at the flower-termination stage and found that the disease lesions on the stems of plants in the T2 and T3 generations decreased by 12.2-33.7% and 32.5-37.3% compared to non-transgenic control plants, respectively, at 7days post-inoculation (dpi). The above results indicate that overexpression of BnaC.CCR2.b leads to an increase in lignin content in the stems, which subsequently leads to increased resistance to S. sclerotiorum. Our findings demonstrate that increasing the lignin content in the stems of B. napus is an important strategy for controlling Sclerotinia.

Upstream Open Reading Frame Mediated Translation of WNK8 Is Required for ABA Response in Arabidopsis.

With no lysine (K) (WNK) kinases comprise a family of serine/threonine kinases belonging to an evolutionary branch of the eukaryotic kinome. These special kinases contain a unique active site and are found in a wide range of eukaryotes. The model plant Arabidopsis has been reported to have 11 WNK members, of which WNK8 functions as a negative regulator of abscisic acid (ABA) signaling. Here, we found that the expression of WNK8 is post-transcriptionally regulated through an upstream open reading frame (uORF) found in its 5' untranslated region (5'-UTR). This uORF has been predicted to encode a conserved peptide named CPuORF58 in both monocotyledons and dicotyledons. The analysis of the published ribosome footprinting studies and the study of the frameshift CPuORF58 peptide with altered repression capability suggested that this uORF causes ribosome stalling. Plants transformed with the native WNK8 promoter driving WNK8 expression were comparable with wild-type plants, whereas the plants transformed with a similar construct with mutated CPuORF58 start codon were less sensitive to ABA. In addition, WNK8 and its downstream target RACK1 were found to synergistically coordinate ABA signaling rather than antagonistically modulating glucose response and flowering in plants. Collectively, these results suggest that the WNK8 expression must be tightly regulated to fulfill the demands of ABA response in plants.

Association of GSTP1 Ile105Val polymorphism with the risk of coronary heart disease: An updated meta-analysis.

BACKGROUND: Numerous case-control studies have investigated the association between GSTP1 Ile105Val polymorphism and CHD risk, but the results from published studies were inconclusive. The present meta-analysis was performed to derive a more precise estimation. METHODS: PubMed, EMBASE, and Web of Science database searches were conducted to retrieve relevant articles. RESULTS: Ultimately, 5,451 CHD cases and 5,561 controls from 15 studies were included. Pooled analysis did not yield any statistically significant association between GSTP1 Ile105Val polymorphism and CHD risk for the overall population (Val vs. Ile: OR, 1.05; 95% CI, 0.93 to 1.18; Val/Val vs. Ile/Ile: OR, 1.09; 95% CI, 0.83 to 1.42; Val/Ile vs. Ile/Ile: OR, 1.09; 95% CI, 0.93 to 1.28; Val/Val vs. Val/Ile+Ile/Ile: OR, 1.04; 95% CI, 0.83 to 1.30; Val/Val+Val/Ile vs. Ile/Ile: OR, 1.14; 95% CI, 0.97 to 1.33). Subgroup analyses and sensitivity analyses indicated that GSTP1 Ile105Val polymorphism was still not associated with an increased risk of CHD. After excluding studies detected by Galbraith plots as major sources of heterogeneity, these relationships were still not significant. CONCLUSIONS: The overall results did not reveal a major role of the GSTP1 Ile105Val polymorphism in modulating CHD risk. Well-designed studies with large sample sizes are needed to validate our findings and explore the possible gene-gene or gene-environment interactions.

Development of a loop-mediated isothermal amplification assay combined with a nanoparticle-based lateral flow biosensor for rapid detection of plasmid-mediated colistin resistance gene mcr-1.

A loop-mediated isothermal amplification assay combined with a nanoparticle-based lateral flow biosensor (LAMP-LFB) was established for the rapid and accurate detection of the mobilized colistin resistance gene (mcr-1), which causes the loss of colistin antibacterial efficacy in clinical treatments. The amplification stage of the assay was completed in 60 min at 63°C, and the reaction products could be visually detected by employing the LFB, which provided a fast (within 2 min) and objective method to evaluate the amplification results. The LAMP assay amplified the target sequences of mcr-1 with high specificity. In pure strains, the detection limit of the LAMP-LFB assay was 360 fg plasmid DNA/reaction, and in spiked feces samples the value was approximately 6.3×103 CFU/mL (~6.3 CFU/reaction), which was tenfold more sensitive than the PCR assay. The results show that the developed LAMP-LFB assay will be a worthy tool for the simple, rapid, specific, and sensitive detection of mcr-1 gene in clinical settings and resource-limited areas.

In vivo FRET-FLIM reveals ER-specific increases in the ABA level upon environmental stresses.

Plant hormone abscisic acid (ABA) is essential for regulating plant growth and various stress responses. ABA-mediated signaling depends on local ABA levels rather than the overall cellular ABA concentration. While cellular concentration of ABA can be detected using Förster resonance energy transfer (FRET)-based ABA probes, direct imaging of subcellular ABA levels remains unsolved. Here, we modified the previously reported ABAleon2.1 and generated a new ABA sensor, named ABAleon2.1_Tao3. Via transient expression in tobacco (Nicotiana tabacum) protoplasts, we targeted ABAleon2.1_Tao3s to the endoplasmic reticulum (ER) membrane with the ABA sensing unit facing the cytosol and the ER, respectively, through a nanobody-epitope-mediated protein interaction. Combining FRET with fluorescence lifetime imaging microscopy, ABA-triggered-specific increases in the fluorescence lifetime of the donor mTurquoise in the ABAleon2.1_Tao3 were detected in both transient assays and stably transformed Arabidopsis plants. In tobacco protoplasts, ER membrane-targeted ABAleon2.1_Tao3s showed a generally higher basal level of ABA in the ER than that in the cytosol and ER-specific alterations in the level of ABA upon environmental cues. In ABAleon2.1_Tao3-transformed Arabidopsis roots, mannitol triggered increases in cytosolic ABA in the division zone and increases in ER ABA in the elongation and maturation zone within 1 h after treatment, both of which were abolished in the bg1-2 mutant, suggesting the requirement for BG1 in osmotic stress-triggered early ABA induction in Arabidopsis roots. These data demonstrate that ABAleon2.1_Tao3s can be used to monitor ABA levels in the cytosol and the ER, providing key information on stress-induced changes in the level of ABA in different subcellular compartments.

RGB1 Regulates Grain Development and Starch Accumulation Through Its Effect on OsYUC11-Mediated Auxin Biosynthesis in Rice Endosperm Cells.

RGB1, a subunit of heterotrimeric G protein, plays important roles in regulating grain size and weight of rice. However, the molecular mechanisms underlying controlling grain filling process by G protein are still largely unclear. In the present study, we show that RGB1 controls not only the grain size but also the grain filling process. Knock-down of RGB1 significantly delayed grain development and reduced starch accumulation and grain weight, which was closely related to the delayed and the lower expression of genes encoding sucrose metabolism and starch biosynthesis related enzymes during grain filling stage. Suppression of RGB1 expression also resulted in the lower auxin content in grains, which was correlated with the lower expression of OsNF-YB1 and OsYUC11 during grain filling stage. Further biochemical evidence showed that OsYUC11 expression was under control of OsNF-YB1 by its interaction with promoter of OsYUC11. Taken together, we propose that RGB1 controls rice grain development and grain filling process by changing auxin homeostasis in endosperm cells. OsNF-YB1, which acts as a key downstream effector of RGB1, interacts directly with the promoter of OsYUC11 and stimulates the OsYUC11 expression, thereby regulating auxin biosynthesis and starch accumulation and grain size.

An updated meta-analysis showed smoking modify the association of GSTM1 null genotype on the risk of coronary heart disease.

Background Oxidative stress is considered to be involved in the pathogenesis of coronary heart disease (CHD). Glutathione-S-transferase (GST) enzymes play important roles in antioxidant defenses and may influence CHD risk. The present meta-analysis was performed to investigate the link between glutathione S-transferase M1 (GSTM1) null genotype and CHD and to get a precise evaluation of interaction between GSTM1 null genotype and smoking by the case-only design. Methods PubMed and EMBASE databases were searched through 15 December 2020 to retrieve articles. Odds ratios (ORs) were pooled using either fixed-effects or random-effects models. Results Thirty-seven studies showed that GSTM1 null genotype was associated with risk of CHD in total population, Caucasians and Asians (for total population, OR = 1.38, 95% confidence interval (CI): 1.15, 1.65; for Caucasians, OR = 1.34, 95% CI: 1.04, 1.72; for Asians, OR = 1.40, 95% CI: 1.11, 1.77). After adjustment for heterogeneity, these relationships were still significant. After adjustment for heterogeneity, case-only analysis of 11 studies showed a positive multiplicative interaction between GSTM1 null genotype and smoking (ever smoking vs. never smoking) (OR = 1.27, 95% CI: 1.08, 1.50; I2 = 0%, P=0.553). Conclusions The overall results indicated that GSTM1 null genotype was associated with a higher risk of CHD, and the association may be affected by smoking status. This is the first meta-analysis to prove a positive effect of the interaction between GSTM1 null genotype and smoking status on the risk of CHD. Well-designed studies are needed to investigate the possible gene-gene or gene-environment interactions.

Identification and molecular characterization of the alternative spliced variants of beta carbonic anhydrase 1 (ßCA1) from Arabidopsis thaliana.

Carbonic anhydrases (CAs) are ubiquitous zinc metalloenzymes that catalyze the interconversion of carbon dioxide and bicarbonate. Higher plants mainly contain the three evolutionarily distinct CA families αCA, ßCA, and γCA, with each represented by multiple isoforms. Alternative splicing (AS) of the CA transcripts is common. However, there is little information on the spliced variants of individual CA isoforms. In this study, we focused on the characterization of spliced variants of ßCA1 from Arabidopsis. The expression patterns and subcellular localization of the individual spliced variants of ßCA1 were examined. The results showed that the spliced variants of ßCA1 possessed different subcellular and tissue distributions and responded differently to environmental stimuli. Additionally, we addressed the physiological role of ßCA1 in heat stress response and its protein-protein interaction (PPI) network. Our results showed that ßCA1 was regulated by heat stresses, and ßca1 mutant was hypersensitive to heat stress, indicating a role for ßCA1 in heat stress response. Furthermore, PPI network analysis revealed that ßCA1 interacts with multiple proteins involved in several processes, including photosynthesis, metabolism, and the stress response, and these will provide new avenues for future investigations of ßCA1.