Dynamic patterns of gene expression and regulatory variation in the maize seed coat.

BACKGROUND: Seed size is an important factor contributing to maize yield, but its molecular mechanism remains unclear. The seed coat, which serves as one of the three components of the maize grain, determines seed size to a certain extent. The seed coat also shares the maternal genotype and is an ideal material for studying heterosis. RESULTS: In this study, the self-pollinated seeds of the maize hybrid Yudan888 and its parental lines were continuously collected from 0 day after pollination (DAP) to 15 DAP for phenotyping, cytological observation and RNA-seq. The phenotypic data showed that 3 DAP and 8 DAP are the best time points to study maize seed coat heterosis. Cytological observations indicated that maize seed coat heterosis might be the result of the coordination between cell number and cell size. Furthermore, the RNA-seq results showed that the nonadditive genes changed significantly between 3 and 8 DAP. However, the number of genes expressed additively was not significantly different. Our findings suggest that seed coat heterosis in hybrid is the result of nonadditive expression caused by dynamic changes in genes at different time points during seed expansion and seed coat development. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment indicated that genes related to DNA replication, cell cycle regulation, circadian rhythms and metabolite accumulation contributed significantly to hybrid seed coat heterosis. CONCLUSION: Maize seed coat phenotyping allowed us to infer that 3 DAP and 8 DAP are important time points in the study of seed coat heterosis. Our findings provide evidence for genes involved in DNA replication, cell cycle regulation, circadian rhythms and metabolite accumulation in hybrid with high or low parental expression as major contributors to hybrid seed coat heterosis.

Circ_0008529 Contributes to Renal Tubular Cell Dysfunction in High Glucose Stress via miR-185-5p/SMAD2 Pathway in Diabetic Nephropathy.

Circular RNA (circRNA) is key regulator of diabetic nephropathy (DN) progression. However, the role of circ_0008529 in DN progression remains to be better deciphered. Cell viability, cell cycle, apoptosis and inflammation were measured by MTS assay, flow cytometry and corresponding assay kits. RT-qPCR was used to assess the expression of circ_0008529, miR-185-5p and SMAD family member 2 (SMAD2). Also, western blotting was performed to measure protein expression. Target relationship was validated by RNA pull-down assay, dual-luciferase reporter assay and RNA immunoprecipitation assay. Urinary exosome was isolated using ultracentrifugation method and identified by transmission electron microscopy. Receiver operating characteristic curve was used to analyze the diagnostic value of circ_0008529 in DN patients. Circ_0008529 and SMAD2 were upregulated, while miR-185-5p was downregulated in high glucose (HG)-induced renal tubular HK-2 cells. Under HG treatment, cell viability and cell cycle process were suppressed, while apoptosis, inflammation and extracellular matrix accumulation were enhanced. However, interfering circ_0008529 could attenuate HG-induced effects, and this protection was abated by miR-185 inhibition or SMAD2 re-expression. Mechanically, circ_0008529 and SMAD2 were competing endogenous RNAs for miR-185-5p via target binding, and circ_0008529 regulated SMAD2 expression via miR-185-5p. Notably, circ_0008529 expression was upregulated in urinary exosomes of DN patients, and showed diagnostic value (Sensitivity: 70.21%; Specificity: 86.67%). Circ_0008529 might be a potential target for DN, which regulated DN progression via miR-185-5p/SMAD2 pathway.

Gene expression variation explains maize seed germination heterosis.

BACKGROUND: Heterosis has been extensively utilized in plant breeding, however, the underlying molecular mechanism remains largely elusive. Maize (Zea mays), which exhibits strong heterosis, is an ideal material for studying heterosis. RESULTS: In this study, there is faster imbibition and development in reciprocal crossing Zhengdan958 hybrids than in their parent lines during seed germination. To investigate the mechanism of heterosis of maize germination, comparative transcriptomic analyses were conducted. The gene expression patterns showed that 1324 (47.27%) and 1592 (66.44%) of the differential expression genes between hybrids and either parental line display parental dominance up or higher levels in the reciprocal cross of Zhengdan958, respectively. Notably, these genes were mainly enriched in metabolic pathways, including carbon metabolism, glycolysis/gluconeogenesis, protein processing in endoplasmic reticulum, etc. CONCLUSION: Our results provide evidence for the higher expression level genes in hybrid involved in metabolic pathways acting as main contributors to maize seed germinating heterosis. These findings provide new insights into the gene expression variation of maize embryos and improve the understanding of maize seed germination heterosis.

Suppression of microRNA168 enhances salt tolerance in rice (Oryza sativa L.).

BACKGROUND: Rice is a salt-sensitive crop. Complex gene regulatory cascades are likely involved in salinity stress in rice roots. microRNA168 (miR168) is a conserved miRNA among different plant species. It in-directly regulates the expression of all miRNAs by targeting gene ARGONAUTE1(AGO1). Short Tandem Target Mimic (STTM) technology is an ideal approach to study miRNA functions by in-activating mature miRNA in plants. RESULTS: In this study, rice miR168 was inactivated by STTM. The T3 generation seedlings of STTM168 exhibited significantly enhanced salt resistance. Direct target genes of rice miR168 were obtained by in silico prediction and further confirmed by degradome-sequencing. PINHEAD (OsAGO1), which was previously suggested to be a plant abiotic stress response regulator. RNA-Seq was performed in root samples of 150mM salt-treated STTM168 and control seedlings. Among these screened 481 differentially expressed genes within STTM168 and the control, 44 abiotic stress response related genes showed significant difference, including four known salt-responsive genes. CONCLUSION: Based on sequencing and qRT-PCR, a "miR168-AGO1-downstream" gene regulation model was proposed to be responsible for rice salt stress response. The present study proved miR168-AGO1 cascade to play important role in rice salinity stress responding, as well as to be applied in agronomic improvement in further.

Suppression of lncRNA GAS6-AS2 alleviates sepsis-related acute kidney injury through regulating the miR-136-5p/OXSR1 axis in vitro and in vivo.

Acute kidney injury (AKI) is a common complication of sepsis and increase morbidity and mortality. Long non-coding RNA (LncRNA) GAS6-AS2 was related to inflammation and apoptosis in different diseases by regulating miRNAs and downstream genes, but its role in AKI remains unclear. Thus, we speculated that GAS6-AS2 might function in sepsis-related AKI via regulating target genes. Here, LPS or CLP was used to establish in vitro or in vivo sepsis-related AKI model. The interactions between GAS6-AS2 and miR-136-5p, and miR-136-5p and OXSR1, were validated by luciferase reporter assay, RNA pull-down, or RIP assay. Cell apoptosis was determined by flow cytometry, Western blotting, or IHC. The kidney injury was evaluated by H&E staining. The expression of GAS6-AS2, miR-136-5p, and OXSR1 was determined by qRT-PCR or Western blotting. We found that GAS6-AS2 was up-regulated in LPS-treated HK2 cells and the CLP-induced rat model. In vitro, GAS6-AS2 knockdown decreased cleaved caspase-3 and bax expression and increased bcl-2 expression. The levels of TNF-α, IL-1ß, and IL-6 were reduced by GAS6-AS2 down-regulation. GAS6-AS2 knockdown ameliorated oxidative stress in the cells, as indicated by the reduced ROS and MDA levels and the elevated SOD level. In vivo, GAS6-AS2 down-regulation decreased urinary NGAL and Kim-1 levels and serum sCr and BUN levels, and H&E proved that the kidney injury was alleviated. GAS6-AS2 knockdown also reduced apoptosis, inflammation, and oxidation induced by CLP in vivo. Mechanically, GAS6-AS2 sponged miR-136-5p which targeted OXSR1. Overall, lncRNA GAS6-AS2 knockdown has the potential to ameliorate sepsis-related AKI, and the mechanism is related to miR-136-5p/OXSR1 axis.

Morphology and Molecular Phylogeny Reveal Five New Species of Laccaria (Hydnangiaceae, Agaricales) from Southern China.

The genus Laccaria is a type of cosmopolitan and ecologically important fungal group. Members can form ectomycorrhizal associations with numerous trees, and some species are common edible fungi in local markets. Although some new species from China are recently published, the species diversity of Laccaria is still unclear in China. In this study, some samples of Laccaria were collected from southern China, and morphological characteristics and phylogenetic analyses based on the multilocus dataset of ITS-LSU-tef1-rpb2 confirmed five new species. Laccaria miniata, L. nanlingensis and L. neovinaceoavellanea were collected from subtropical broad-leaved forests, and L. rufobrunnea and L. umbilicata were collected from subtropical mixed forests of southwest China. Full descriptions, illustrations, comparisons with similar species and phylogenetic analysis are provided.

Comparative transcriptomics analysis at the key stage of maize ear development dissect heterosis.

Important traits related to maize (Zea mays L.) grain yield, such as kernel row number, ear length, kernel number per row, are determined during the development of female inflorescence. There is a significant positive correlation between yield component and the activity of inflorescence meristem (IM). To find the key stage of heterosis in the development of the ear, immature ears (from the IM stage until the end of the floral meristem [FM] stage) of Yudan888 and its parent lines were sampled to assay phenotype and for comparative transcriptomics analysis. The immature ear length of Yudan888 at the IM stage fitted an additive (mid-parental) model, but it showed high parental dominance at the spikelet-pair meristem (SPM) stage. Comparative analysis of transcriptomes suggested significant differences between additive and nonadditive expression patterns for different developmental stages. The number of distinct maternal or paternal genes (DMP) (genes expressed only in one parental line and their hybrid but silenced in another line) was greater than ABF1 (genes expressed in both parental lines but silenced in hybrid) at each stage. Gene Ontology (GO) enrichment suggested that the cell redox homeostasis genes with overdominance expression patterns in hybrids have an important contribution to heterosis. According to our research, an ear length heterosis network was established. The discovery of the inflection point for ear length heterosis allows us for inferring that the transition state of IM to SPM may be the starting point of ear length heterosis. These findings improved the understanding of maize ear length heterosis.

[Controlled study on therapeutic effect of vessel pricking therapy and western medication for treatment of Henoch-Schonlein purpura nephritis].

OBJECTIVE: To compare the difference of therapeutic effects between vessel pricking therapy and Prednisone for treatment of Henoch-Schonlein purpura nephritis. METHODS: Seventy cases of acute purpura nephritis syndrome were randomly divided into an observation group (40 cases) and a control group (30 cases). Patients in observation group were differentiated into sthenia and asthenia syndromes. Vessel pricking therapy was applied at Hegu (LI 4), Quchi (LI 11), Xuehai (SP 10) etc. by triangular needle for sthenia symptom; shallow needling was used at Pishu (BL 20), Shenshu (BL 23), Zusanli (ST 36) etc. by filiform needle. The control group was treated with oral admi-nidtration of Prednisone. The symptom score of TCM, 24 h urinary protein, red blood cell count of urinary sediment of both groups were observed before and after treatment and therapeutic effects were compared. RESULTS: The total effective rate of 92.5% (37/40) in observation group was superior to that of 80.0% (24/30) in control group, and there was a significant difference between two groups (P < 0.05); the symptom score of TCM, 24 h urinary protein, red blood cell count of urinary sediment were all improved in both groups after treatment (all P < 0.05), and moreover, the improvement in observation group was superior to that of control group (all P < 0.05); after treatment, the symptom score of TCM of sthenia syndrome was lower than that of asthenia syndrome in observation group (P < 0.05). CONCLUSION: Vessel pricking therapy has a significant therapeutic effect for treatment of Henoch-Schonlein purpura nephritis, superior to that of oral administration of Prednisone, and the therapeutic effect is better for treating sthenia syndrome than for asthenia syndrome.