A CYP78As-small grain4-coat protein complex â ¡ pathway promotes grain size in rice.

CYP78A, a cytochrome P450 subfamily that includes rice (Oryza sativa L.) BIG GRAIN2 (BG2, CYP78A13) and Arabidopsis thaliana KLUH (KLU, CYP78A5), generate an unknown mobile growth signal (referred to as a CYP78A-derived signal) that increases grain (seed) size. However, the mechanism by which the CYP78A pathway increases grain size remains elusive. Here, we characterized a rice small grain mutant, small grain4 (smg4), with smaller grains than its wild type due to restricted cell expansion and cell proliferation in spikelet hulls. SMG4 encodes a multidrug and toxic compound extrusion (MATE) transporter. Loss of function of SMG4 causes smaller grains while overexpressing SMG4 results in larger grains. SMG4 is mainly localized to endoplasmic reticulum (ER) exit sites (ERESs) and partially localized to the ER and Golgi. Biochemically, SMG4 interacts with coat protein complex Ⅱ (COPⅡ) components (Sar1, Sec23, and Sec24) and CYP78As (BG2, GRAIN LENGTH 3.2 [GL3.2], and BG2-LIKE 1 [BG2L1]). Genetically, SMG4 acts, at least in part, in a common pathway with Sar1 and CYP78As to regulate grain size. In summary, our findings reveal a CYP78As-SMG4-COPⅡ regulatory pathway for grain size in rice, thus providing new insights into the molecular and genetic regulatory mechanism of grain size.

Functional Diversification of Sec13 Isoforms for Storage Protein Trafficking in Rice Endosperm Cells.

Coat protein complex II (COPII) vesicles play crucial roles in mediating the endoplasmic reticulum (ER) exit of newly synthesized proteins to the Golgi in eukaryotic cells. However, the molecular functions of COPII components and their functional diversifications in plant seeds remain obscure. Here, we showed that the rice (Oryza sativa) glutelin precursor accumulation12 (gpa12) mutant is defective in storage protein export from the ER, resulting in the formation of aggregated protein bodies. Map-based cloning revealed that GPA12 encodes a COPII outer layer protein, Sec13a, that mainly localizes to endoplasmic reticulum exit sites (ERES) and partially localizes to the Golgi. Biochemical experiments verified that Sec13a physically interacts with Sec31 and Sec16, and mutation in Sec13 compromises its interaction with Sec31 and Sec16, thereby affecting the membrane association of the inner complex components Sar1b and Sec23c. Apart from Sec13a, the rice genome encodes two other Sec13 isoforms, Sec13b and Sec13c. Notably, we observed an abnormal accumulation of globular ER structures in the sec13bc double mutant but not in the single mutants, suggesting a functional redundancy of Sec13b and Sec13c in modulating ER morphology. Taken together, our results substantiated that Sec13a plays an important role in regulating storage protein export from the ER, while Sec13b and Sec13c are required for maintaining ER morphology in rice endosperm cells. Our findings provide insights into the functional diversification of COPII components in plants.

Systematical characterization of Rab7 gene family in Gossypium and potential functions of GhRab7B3-A gene in drought tolerance.

BACKGROUND: Cotton serves as a primary source of natural fibers crucial for the textile industry. However, environmental elements such as drought have posed challenges to cotton cultivation, resulting in adverse impacts on both production and fiber quality. Improving cotton's resilience to drought could mitigate yield losses and foster the expansion of cotton farming. Rab7 protein, widely present in organisms, controls the degradation and recycling of cargo, and has a potential role in biotic and abiotic tolerance. However, comprehensive exploration of the Rab7 gene family in Gossypium remains scarce. RESULTS: Herein, we identified a total of 10, 10, 20, and 20 Rab7 genes through genome-wide analysis in Gossypium arboreum, Gossypium raimondii, Gossypium hirsutum, and Gossypium barbadense, respectively. Collinearity analysis unveiled the pivotal role of whole genome or segmental duplication events in the expansion of GhRab7s. Study of gene architecture, conserved protein motifs, and domains suggested the conservation of structure and function throughout evolution. Exploration of cis-regulatory elements revealed the responsiveness of GhRab7 genes to abiotic stress, corroborated by transcriptome analysis under diverse environmental stresses. Notably, the greatly induced expression of GhRab7B3-A under drought treatment prompted us to investigate its function through virus-induced gene silencing (VIGS) assays. Silencing GhRab7B3-A led to exacerbated dehydration and wilting compared with the control. Additionally, inhibition of stomatal closure, antioxidant enzyme activities and expression patterns of genes responsive to abiotic stress were observed in GhRab7B3-A silenced plants. CONCLUSIONS: This study sheds light on Rab7 members in cotton, identifies a gene linked to drought stress, and paves the way for additional investigation of Rab7 genes associated with drought stress tolerance.

Membrane-Based Preparation Process and Antioxidant and Anti-AGEs Activities of a Novel Propolis Ultrafiltrate.

Propolis is one functional supplement with hundreds of years of usage. However, it's rarely consumed directly for its resinous property. Herein, a pre-treated process which can remove the impurity while preserve its bioactivities is needed to maximise its therapeutic opportunities. In the present study, a membrane-based ultrafiltration process was developed on a KM1812-NF experimental instrument. Using Brazilian green propolis as testing material, all experimental steps and parameters were sequentially optimized. In addition, a mathematical model was developed to fit the process. As a result, the optimum solvent was 60 % ethanol adjusted to pH 8-9, while the optimum MWCO (molecular weight cut-off) value of membrane was 30 KDa. The membrane filtration dynamic model fitted with the function y=(ax+b)/(1+cx+dx2 ). The resulting propolis ultrafiltrate from Brazilian green propolis, termed P30K, contains the similar profile of flavonoids and phenolic acids as raw propolis. Meanwhile, the ORAC (oxygen radical absorbance capacity) value of P30K is 11429.45±1557.58 µM TE/g and the IC50 value of inhibition of fluorescent AGEs (advanced glycation end products) formation is 0.064 mg/mL. Our work provides an innovative alternative process for extraction of active compounds from propolis and reveals P30K as an efficient therapeutic antioxidant.

The MON1-CCZ1 complex plays dual roles in autophagic degradation and vacuolar protein transport in rice.

Autophagy is a highly conserved cellular program in eukaryotic cells which mediates the degradation of cytoplasmic components through the lysosome, also named the vacuole in plants. However, the molecular mechanisms underlying the fusion of autophagosomes with the vacuole remain unclear. Here, we report the functional characterization of a rice (Oryza sativa) mutant with defects in storage protein transport in endosperm cells and accumulation of numerous autophagosomes in root cells. Cytological and immunocytochemical experiments showed that this mutant exhibits a defect in the fusion between autophagosomes and vacuoles. The mutant harbors a loss-of-function mutation in the rice homolog of Arabidopsis thaliana MONENSIN SENSITIVITY1 (MON1). Biochemical and genetic evidence revealed a synergistic interaction between rice MON1 and AUTOPHAGY-RELATED 8a in maintaining normal growth and development. In addition, the rice mon1 mutant disrupted storage protein sorting to protein storage vacuoles. Furthermore, quantitative proteomics verified that the loss of MON1 function influenced diverse biological pathways including autophagy and vacuolar transport, thus decreasing the transport of autophagic and vacuolar cargoes to vacuoles. Together, our findings establish a molecular link between autophagy and vacuolar protein transport, and offer insights into the dual functions of the MON1-CCZ1 (CAFFEINE ZINC SENSITIVITY1) complex in plants.

NLRP3 Plays a Key Role in Antihelminth Immunity in the Enteral and Parenteral Stages of Trichinella spiralis-Infected Mice.

Trichinellosis is an important foodborne zoonosis, and no effective treatments are yet available. Nod-like receptor (NLR) plays a critical role in the host response against nematodes. Therefore, we aimed to explore the role of the NLRP3 inflammasome (NLRP3) during the adult, migrating, and encysted stages of Trichinella spiralis infection. The mice were treated with the specific NLRP3 inhibitor MCC950 after inoculation with T. spiralis. Then, the role that NLRP3 plays during T. spiralis infection of mice was evaluated using enzyme-linked immunosorbent assay (ELISA), Western blotting, flow cytometry, histopathological evaluation, bone marrow-derived macrophage (BMDM) stimulation, and immunofluorescence. The in vivo results showed that NLRP3 enhanced the Th1 immune response in the adult and migrating stages and weakened the Th2 immune response in the encysted stage. NLRP3 promoted the release of proinflammatory factors (interferon gamma [IFN-γ]) and suppressed the release of anti-inflammatory factors (interleukin 4 [IL-4]). Pathological changes were also improved in the absence of NLRP3 in mice during T. spiralis infection. Importantly, a significant reduction in adult worm burden and muscle larvae burden at 7 and 35 days postinfection was observed in mice treated with the specific NLRP3 inhibitor MCC950. In vitro, we first demonstrated that NLRP3 in macrophages can be activated by T. spiralis proteins and promotes IL-1ß and IL-18 release. This study revealed that NLRP3 is involved in the host response to T. spiralis infection and that targeted inhibition of NLRP3 enhanced the Th2 response and accelerated T. spiralis expulsion. These findings may help in the development of protocols for controlling trichinellosis.

A deleterious Sar1c variant in rice inhibits export of seed storage proteins from the endoplasmic reticulum.

KEY MESSAGE: We identified a dosage-dependent dominant negative form of Sar1c, which confirms the essential role of COPII system in mediating ER export of storage proteins in rice endosperm. Higher plants accumlate large amounts of seed storage proteins (SSPs). However, mechanisms underlying SSP trafficking are largely unknown, especially the ER-Golgi anterograde process. Here, we showed that a rice glutelin precursor accumulation13 (gpa13) mutant exhibited floury endosperm and overaccumulated glutelin precursors, which phenocopied the reported RNAi-Sar1abc line. Molecular cloning revealed that the gpa13 allele encodes a mutated Sar1c (mSar1c) with a deletion of two conserved amino acids Pro134 and Try135. Knockdown or knockout of Sar1c alone caused no obvious phenotype, while overexpression of mSar1c resulted in seedling lethality similar to the gpa13 mutant. Transient expression experiment in tobacco combined with subcellular fractionation experiment in gpa13 demonstrated that the expression of mSar1c affects the subcellular distribution of all Sar1 isoforms and Sec23c. In addition, mSar1c failed to interact with COPII component Sec23. Conversely, mSar1c competed with Sar1a/b/d to interact with guanine nucleotide exchange factor Sec12. Together, we identified a dosage-dependent dominant negative form of Sar1c, which confirms the essential role of COPII system in mediating ER export of storage proteins in rice endosperm.

Rice STOMATAL CYTOKINESIS DEFECTIVE2 regulates cell expansion by affecting vesicular trafficking in rice.

Vesicular trafficking plays critical roles in cell expansion in yeast and mammals, but information linking vesicular trafficking and cell expansion in plants is limited. Here, we isolated and characterized a rice (Oryza sativa) mutant, decreased plant height 1-1 (dph1-1), which exhibited a wide spectrum of developmental phenotypes, including reduced plant height and smaller panicles and grains. Cytological analysis revealed that limited cell expansion was responsible for the dph1-1 mutant phenotype compared to the wild-type. Map-based cloning revealed that DPH1 encodes a plant-specific protein, OsSCD2, which is homologous to Arabidopsis (Arabidopsis thaliana) STOMATAL CYTOKINESIS DEFECTIVE2 (SCD2). Subcellular localization revealed that OsSCD2 is associated with clathrin. Confocal microscopy showed that the dph1-1 mutant has defective endocytosis and post-Golgi trafficking. Biochemical and confocal data indicated that OsSCD2 physically interacts with OsSCD1 and that they are associated with intracellular structures that colocalize with microtubules. Furthermore, we found that cellulose synthesis was affected in the dph1-1 mutant, evidenced by reduced cellulose synthase gene accumulation at the transcript and protein levels, most likely resulting from an impaired localization pattern. Our results suggest that OsSCD2 is involved in clathrin-related vesicular trafficking with an important role in maintaining plant growth in rice.

GPA5 Encodes a Rab5a Effector Required for Post-Golgi Trafficking of Rice Storage Proteins.

Dense vesicles (DVs) are vesicular carriers, unique to plants, that mediate post-Golgi trafficking of storage proteins to protein storage vacuoles (PSVs) in seeds. However, the molecular mechanisms regulating the directional targeting of DVs to PSVs remain elusive. Here, we show that the rice (Oryza sativa) glutelin precursor accumulation5 (gpa5) mutant is defective in directional targeting of DVs to PSVs, resulting in discharge of its cargo proteins into the extracellular space. Molecular cloning revealed that GPA5 encodes a plant-unique phox-homology domain-containing protein homologous to Arabidopsis (Arabidopsis thaliana) ENDOSOMAL RAB EFFECTOR WITH PX-DOMAIN. We show that GPA5 is a membrane-associated protein capable of forming homodimers and that it is specifically localized to DVs in developing endosperm. Colocalization, biochemical, and genetic evidence demonstrates that GPA5 acts in concert with Rab5a and VPS9a to regulate DV-mediated post-Golgi trafficking to PSVs. Furthermore, we demonstrated that GPA5 physically interacts with a class C core vacuole/endosome tethering complex and a seed plant-specific VAMP727-containing R-soluble N-ethylmaleimide sensitive factor attachment protein receptor complex. Collectively, our results suggest that GPA5 functions as a plant-specific effector of Rab5a required for mediating tethering and membrane fusion of DVs with PSVs in rice endosperm.

Structural Evolution and Properties of Praseodymium Antimony Oxochlorides Based on a Chain-like Tertiary Building Unit.

Unveiling the structural evolution of single-crystalline compounds based on certain building units may help greatly in guiding the design of complex structures. Herein, a series of praseodymium antimony oxohalide crystals have been isolated under solvothermal conditions via adjusting the solvents used, that is, [HN(CH2CH3)3][FeII(2,2'-bpy)3][Pr4Sb12O18Cl15]·EtOH (1) (2,2'-bpy = 2,2'-bipyridine), [HN(CH2CH3)3][FeII(2,2'-bpy)3]2[Pr4Sb12O18Cl14)2Cl]·N(CH2CH3)3·2H2O (2), and (H3O)[Pr4Sb12O18Cl12.5(TEOA)0.5]·2.5EtOH (3) (TEOA = mono-deprotonated triethanolamine anion). Single-crystal X-ray diffraction analysis revealed that all the three structures feature an anionic zig-zag chain of [Pr4Sb12O18Cl15-x]n as the tertiary building unit (TBU), which is formed by interconnections of praseodymium antimony oxochloride clusters (denoted as {Pr4Sb12}) as secondary building units. Interestingly, different arrangements or linkages of chain-like TBUs result in one-dimensional, two-dimensional layered, and three-dimensional structures of 1, 2, and 3, respectively, thus demonstrating clearly the structural evolution of metal oxohalide crystals. The title compounds have been characterized by elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and UV-Vis spectroscopy, and the photodegradation for methyl blue in an aqueous solution of compound 1 has been preliminarily studied. This work offers a way to deeply understand the assembly process of intricate lanthanide-antimony(III) oxohalide structures at the atomic level.

Post-Golgi trafficking of rice storage proteins requires the small GTPase Rab7 activation complex MON1-CCZ1.

Protein storage vacuoles (PSVs) are unique organelles that accumulate storage proteins in plant seeds. Although morphological evidence points to the existence of multiple PSV-trafficking pathways for storage protein targeting, the molecular mechanisms that regulate these processes remain mostly unknown. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation7 (gpa7) mutant, which over-accumulates 57-kDa glutelin precursors in dry seeds. Cytological and immunocytochemistry studies revealed that the gpa7 mutant exhibits abnormal accumulation of storage prevacuolar compartment-like structures, accompanied by the partial mistargeting of glutelins to the extracellular space. The gpa7 mutant was altered in the CCZ1 locus, which encodes the rice homolog of Arabidopsis (Arabidopsis thaliana) CALCIUM CAFFEINE ZINC SENSITIVITY1a (CCZ1a) and CCZ1b. Biochemical evidence showed that rice CCZ1 interacts with MONENSIN SENSITIVITY1 (MON1) and that these proteins function together as the Rat brain 5 (Rab5) effector and the Rab7 guanine nucleotide exchange factor (GEF). Notably, loss of CCZ1 function promoted the endosomal localization of vacuolar protein sorting-associated protein 9 (VPS9), which is the GEF for Rab5 in plants. Together, our results indicate that the MON1-CCZ1 complex is involved in post-Golgi trafficking of rice storage protein through a Rab5- and Rab7-dependent pathway.

Subunit E isoform 1 of vacuolar H+-ATPase OsVHA enables post-Golgi trafficking of rice seed storage proteins.

Dense vesicles (DVs) are Golgi-derived plant-specific carriers that mediate post-Golgi transport of seed storage proteins in angiosperms. How this process is regulated remains elusive. Here, we report a rice (Oryza sativa) mutant, named glutelin precursor accumulation8 (gpa8) that abnormally accumulates 57-kDa proglutelins in the mature endosperm. Cytological analyses of the gpa8 mutant revealed that proglutelin-containing DVs were mistargeted to the apoplast forming electron-dense aggregates and paramural bodies in developing endosperm cells. Differing from previously reported gpa mutants with post-Golgi trafficking defects, the gpa8 mutant showed bent Golgi bodies, defective trans-Golgi network (TGN), and enlarged DVs, suggesting a specific role of GPA8 in DV biogenesis. We demonstrated that GPA8 encodes a subunit E isoform 1 of vacuolar H+-ATPase (OsVHA-E1) that mainly localizes to TGN and the tonoplast. Further analysis revealed that the luminal pH of the TGN and vacuole is dramatically increased in the gpa8 mutant. Moreover, the colocalization of GPA1 and GPA3 with TGN marker protein in gpa8 protoplasts was obviously decreased. Our data indicated that OsVHA-E1 is involved in endomembrane luminal pH homeostasis, as well as maintenance of Golgi morphology and TGN required for DV biogenesis and subsequent protein trafficking in rice endosperm cells.

I-125 seeds brachytherapy with transcatheter arterial chemoembolization for subcapsular hepatocellular carcinoma.

BACKGROUND: I-125 seeds brachytherapy (ISB) has been used to improve the clinical effectiveness of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). We aim to appraise the safety and clinical efficacy of combined ISB and TACE for the treatment of subcapsular HCC. MATERIALS AND METHODS: A retrospective investigative study extending from January 2017 to December 2020, involved individuals suffering from subcapsular HCC, who were subjected to TACE treatment with or without ISB in our center. The clinical effectiveness was compared between 2 groups. RESULTS: Sixty-four patients, in total, with subcapsular HCC had to undergo TACE with (n = 32) or without (n = 32) ISB in our center. After CT-guided ISB, only 2 (6.3%) patients experienced a self-limited pneumothorax. Combined treatment resulted in a significantly higher complete response (56.3% vs. 18.8%, P = 0.002) and total response (90.7% vs. 59.4%, P = 0.004) rates than that of TACE alone. In comparison to the TACE alone group, the median progression-free survival was substantially longer in the combined treatment group (11 months vs. 5 months, P = 0.016). Further, 15 and 28 patients in combined and TACE alone groups respectively died within the follow-up. The median OS was comparable between combined and TACE alone groups (22 months vs. 18 months, P = 0.529). CONCLUSIONS: Combined TACE and ISB therapy is a safe treatment method for individuals suffering from subcapsular HCC. When compared, combined treatment had significantly enhanced clinical efficacy as a subcapsular HCC therapy, in comparison to TACE alone.

Trichinella spiralis infection ameliorates the severity of Citrobacter rodentium-induced experimental colitis in mice.

Trichinellosis is a food-borne zoonotic parasitic disease that causes serious harm to human health and the pig breeding industry. However, there are reports that Trichinella spiralis (T. spiralis) infection can treat autoimmune diseases, including enteritis and experimental autoimmune encephalitis (EAE). However, research on the mechanism of T. spiralis infection in infectious enteritis has not been fully elucidated. Therefore, this experiment used Citrobacter rodentium (C. rodentium) to induce colitis in mouse models and explored its underlying mechanisms. In this experiment, a total of 72 C57BL/6 mice were randomly divided into four groups. Experimental mice in the TS and TS + CR groups were orally inoculated with individual T. spiralis larvae. At 21 days postinfection (dpi) with T. spiralis, experimental animals in the CR and TS + CR groups were inoculated by orogastric gavage with C. rodentium. The control group received PBS only. The results indicated that the weight loss and macroscopic and microscopic colon damage of mice in the TS + CR group were significantly decreased compared with those observed in the CR group. The results of flow cytometry showed that the expression levels of IL-4, IL-10 and CD4+CD25+Foxp3+ Tregs were increased (P < 0.05), while the expression levels of IFN-γ, IL-12 and IL-17 were decreased in the spleens and MLNs of the TS + CR experimental mice compared with the colitis model mice. ELISA results revealed that the TS + CR group not only elicited a strong IgG1 response (P < 0.01) but also a low level of IgG2a response (P < 0.05) relative to the CR group. The above results demonstrated that prior exposure of mice to T. spiralis infection ameliorated the severity of C. rodentium-induced infectious colitis.

Rice FLOURY ENDOSPERM 18 encodes a pentatricopeptide repeat protein required for 5' processing of mitochondrial nad5 messenger RNA and endosperm development.

Pentatricopeptide repeat (PPR) proteins, composing one of the largest protein families in plants, are involved in RNA binding and regulation of organelle RNA metabolism at the post-transcriptional level. Although several PPR proteins have been implicated in endosperm development in rice (Oryza sativa), the molecular functions of many PPRs remain obscure. Here, we identified a rice endosperm mutant named floury endosperm 18 (flo18) with pleiotropic defects in both reproductive and vegetative development. Map-based cloning and complementation tests showed that FLO18 encodes a mitochondrion-targeted P-type PPR protein with 15 PPR motifs. Mitochondrial function was disrupted in the flo18 mutant, as evidenced by decreased assembly of Complex I in the mitochondrial electron transport chain and altered mitochondrial morphology. Loss of FLO18 function resulted in defective 5'-end processing of mitochondrial nad5 transcripts encoding subunit 5 of nicotinamide adenine dinucleotide hydrogenase. These results suggested that FLO18 is involved in 5'-end processing of nad5 messenger RNA and plays an important role in mitochondrial function and endosperm development.

Ubiquitin Specific Protease 15 Has an Important Role in Regulating Grain Width and Size in Rice.

Ubiquitination and deubiquitination are reversible processes that play crucial roles in regulating organ size in plants. However, information linking deubiquitination and seed size in rice (Oryza sativa) is limited. Here, we characterized a dominant large-grain mutant, large grain1-D (lg1-D), with a 30.8% increase in seed width and a 34.5% increase in 1,000-grain weight relative to the wild type. The lg1-D mutant had more cells oriented in the lateral direction of the spikelet hull compared with the wild type. Map-based cloning showed that LG1 encodes a constitutively expressed ubiquitin-specific protease15 (OsUBP15) that possesses deubiquitination activity in vitro. Loss-of-function and down-regulated expression of OsUBP15 produced narrower and smaller grains than the control. A set of in vivo experiments indicated that the mutant Osubp15 had enhanced protein stability relative to wild-type OsUBP15. Further experiments verified that OsDA1 directly interacted with OsUBP15. Genetic data indicated that OsUBP15 and GRAIN WIDTH 2 (GW2) were not independent in regulating grain width and size. In summary, we identified OsUBP15 as a positive regulator of grain width and size in rice and provide a promising strategy for improvement of grain yield by pyramiding OsUBP15 and gw2.

The small GTPase Rab5a and its guanine nucleotide exchange factors are involved in post-Golgi trafficking of storage proteins in developing soybean cotyledon.

Storage protein is the most abundant nutritional component in soybean seed. Morphology-based evidence has verified that storage proteins are initially synthesized on the endoplasmic reticulum, and then follow the Golgi-mediated pathway to the protein storage vacuole. However, the molecular mechanisms of storage protein trafficking in soybean remain unknown. Here, we clone the soybean homologs of Rab5 and its guanine nucleotide exchange factor (GEF) VPS9. GEF activity combined with yeast two-hybrid assays demonstrated that GmVPS9a2 might specifically act as the GEF of the canonical Rab5, while GmVPS9b functions as a common activator for all Rab5s. Subcellular localization experiments showed that GmRab5a was dually localized to the trans-Golgi network and pre-vacuolar compartments in developing soybean cotyledon cells. Expression of a dominant negative variant of Rab5a, or RNAi of either Rab5a or GmVPS9s, significantly disrupted trafficking of mRFP-CT10, a cargo marker for storage protein sorting, to protein storage vacuoles in maturing soybean cotyledons. Together, our results systematically revealed the important role of GmRab5a and its GEFs in storage protein trafficking, and verified the transient expression system as an efficient approach for elucidating storage protein trafficking mechanisms in seed.

[Clinical features of coronavirus disease 2019 in children aged <18 years in Jiangxi, China: an analysis of 23 cases].

OBJECTIVE: To study the clinical features of coronavirus disease 2019 (COVID-19) in children aged <18 years. METHODS: A retrospective analysis was performed from the medical data of 23 children, aged from 3 months to 17 years and 8 months, who were diagnosed with COVID-19 in Jiangxi, China from January 21 to February 29, 2020. RESULTS: Of the 23 children with COVID-19, 17 had family aggregation. Three children (13%) had asymptomatic infection, 6 (26%) had mild type, and 14 (61%) had common type. Among these 23 children, 16 (70%) had fever, 11 (48%) had cough, 8 (35%) had fever and cough, and 8 (35%) had wet rales in the lungs. The period from disease onset or the first nucleic acid-positive detection of SARS-CoV-2 to the virus nucleic acid negative conversion was 6-24 days (median 12 days). Of the 23 children, 3 had a reduction in total leukocyte count, 2 had a reduction in lymphocytes, 2 had an increase in C-reactive protein, and 2 had an increase in D-dimer. Abnormal pulmonary CT findings were observed in 12 children, among whom 9 had patchy ground-glass opacities in both lungs. All 23 children received antiviral therapy and were recovered. CONCLUSIONS: COVID-19 in children aged <18 years often occurs with family aggregation, with no specific clinical manifestation and laboratory examination results. Most of these children have mild symptoms and a good prognosis. Epidemiological history is of particular importance in the diagnosis of COVID-19 in children aged <18 years.

OsNHX5-mediated pH homeostasis is required for post-Golgi trafficking of seed storage proteins in rice endosperm cells.

BACKGROUND: As the major storage protein in rice seeds, glutelins are synthesized at the endoplasmic reticulum (ER) as proglutelins and transported to protein storage vacuoles (PSVs) called PBIIs (Protein body IIs), where they are cleaved into mature forms by the vacuolar processing enzymes. However, the molecular mechanisms underlying glutelin trafficking are largely unknown. RESULTS: In this study, we report a rice mutant, named glutelin precursor accumulation6 (gpa6), which abnormally accumulates massive proglutelins. Cytological analyses revealed that in gpa6 endosperm cells, proglutelins were mis-sorted, leading to the presence of dense vesicles (DVs) and the formation paramural bodies (PMBs) at the apoplast, consequently, smaller PBII were observed. Mutated gene in gpa6 was found to encode a Na+/H+ antiporter, OsNHX5. OsNHX5 is expressed in all tissues analyzed, and its expression level is much higher than its closest paralog OsNHX6. The OsNHX5 protein colocalizes to the Golgi, the trans-Golgi network (TGN) and the pre-vacuolar compartment (PVC) in tobacco leaf epidermal cells. In vivo pH measurements indicated that the lumens of Golgi, TGN and PVC became more acidic in gpa6. CONCLUSIONS: Our results demonstrated an important role of OsNHX5 in regulating endomembrane luminal pH, which is essential for seed storage protein trafficking in rice.