OsNAC103, an NAC transcription factor negatively regulates plant height in rice.

MAIN CONCLUSION: OsNAC103 negatively regulates rice plant height by influencing the cell cycle and crosstalk of phytohormones. Plant height is an important characteristic of rice farming and is directly related to agricultural yield. Although there has been great progress in research on plant growth regulation, numerous genes remain to be elucidated. NAC transcription factors are widespread in plants and have a vital function in plant growth. Here, we observed that the overexpression of OsNAC103 resulted in a dwarf phenotype, whereas RNA interference (RNAi) plants and osnac103 mutants showed no significant difference. Further investigation revealed that the cell length did not change, indicating that the dwarfing of plants was caused by a decrease in cell number due to cell cycle arrest. The content of the bioactive cytokinin N6-Δ2-isopentenyladenine (iP) decreased as a result of the cytokinin synthesis gene being downregulated and the enhanced degradation of cytokinin oxidase. OsNAC103 overexpression also inhibited cell cycle progression and regulated the activity of the cell cyclin OsCYCP2;1 to arrest the cell cycle. We propose that OsNAC103 may further influence rice development and gibberellin-cytokinin crosstalk by regulating the Oryza sativa homeobox 71 (OSH71). Collectively, these results offer novel perspectives on the role of OsNAC103 in controlling plant architecture.

Impact of environmental factors on diversity of fungi in sediments from the Shenzhen River Estuary.

In this study, to explore the relationship between environmental factors and fungal diversity in the Shenzhen River ecosystem, multiple methods including chemical analysis, culture isolation, qPCR analysis of fungal ITS region and ITS-based Illumina next-generation-sequencing were integrated. A total of 115 isolates were finally isolated and could be classified into 23 genera. Top three abundant genera isolated were Meyerozyma (18 strains), Aspergillus (17 strains) and Penicillium (14 strains). Based on the Illumina sequencing approach, 829 OTUs were affiliated to seven phyla, 17 known classes, and 162 genera, indicating the Shenzhen estuary sediments are rich in fungal diversity. The major fungal genera were Meyerozyma, Trichoderma and Talaromyces. Environmental factors showed a gradient change in Shenzhen estuary, and fungal abundance was only significantly correlated with NH4+. Shannon index was significantly correlated with pH and IC (P < 0.05). Principal coordinate analysis based on OTU level grouped into three clusters among sampling sites along with the IC and pH gradient. Functional guilds analysis suggests most of the fungi in this studying area were almost all saprotrophs, suggesting a large number of saprophytic fungi may play a significant role in the organic matter decomposition and nutrient cycling process. In summary, this study will deepen our understanding of fungi community in Shenzhen River ecosystem and their distribution and potential function shaped by environmental factors.

Halomonas dongshanensis sp. nov., isolated from the seawater of Dongshan Island.

A taxonomic study was carried out on strain yzlin-01T, isolated from Dongshan Island seawater. The bacterium was Gram-stain-negative, catalase-positive, oxidase-negative, rod-shaped, and motile by polar flagella. Growth was observed at temperatures of 10-40 °C, at salinities of 0.5-18 %, and at pH of 6-10. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain yzlin-01T belonged to the genus Halomonas, with the highest sequence similarity to Halomonas malpeensis YU-PRIM-29T (96.7 %), followed by Halomonas johnsoniae T68687T (96.4 %) and Halomonas gomseomensis M12T (96.4 %), and other species of the genus Halomonas (93.4-96.3 %). The ANI and digital DNA-DNA hybridization estimate values between strain yzlin-01T and the closest type strain Halomonas malpeensis YU-PRIM-29T were 77.44 and 21.6 %, respectively. The principal fatty acids were summed feature 8 (consisting of C18 : 1 ω7c and/or C18 : 1 ω6c; 55.7 %), C16 : 0 (20.6 %), C12 : 0 3-OH (6.8 %), summed feature 3 (consisting of C16 : 1 ω7c and/or C16 : 1 ω6c; 5.1 %). The G+C content of the chromosomal DNA was 60.0 mol %. The respiratory quinone was identified as Q-9 (100 %). Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminophospholipid, and three unidentified phospholipids were present. Combined genotypic and phenotypic data suggest that strain yzlin-01T represents a novel species within the genus Halomonas, for which the name Halomonas dongshanensis sp. nov. is proposed, with the type strain yzlin-01T (=GDMCC 1.3202T=KCTC 92467T).

Health Status Assessment of Diesel Engine Valve Clearance Based on BFA-BOA-VMD Adaptive Noise Reduction and Multi-Channel Information Fusion.

Regarding the problem of the valve gap health status being difficult to assess due to the complex composition of the condition monitoring signal during the operation of the diesel engine, this paper proposes an adaptive noise reduction and multi-channel information fusion method for the health status assessment of diesel engine valve clearance. For the problem of missing fault information of single-channel sensors in condition monitoring, we built a diesel engine valve clearance preset simulation test bench and constructed a multi-sensor acquisition system to realize the acquisition of diesel engine multi-dimensional cylinder head signals. At the same time, for the problem of poor adaptability of most signal analysis methods, the improved butterfly optimization algorithm by the bacterial foraging algorithm was adopted to adaptively optimize the key parameter for variational mode decomposition, with discrete entropy as the fitness value. Then, to reduce the uncertainty of artificially selecting fault characteristics, the characteristic parameters with a higher recognition degree of diesel engine signal were selected through characteristic sensitivity analysis. To achieve an effective dimensionality reduction integration of multi-channel features, a stacked sparse autoencoder was used to achieve deep fusion of the multi-dimensional feature values. Finally, the feature samples were entered into the constructed one-dimensional convolutional neural network with a four-layer parameter space for training to realize the health status assessment of the diesel engine. In addition, we verified the effectiveness of the method by carrying out valve degradation simulation experiments on the diesel engine test bench. Experimental results show that, compared with other common evaluation methods, the method used in this paper has a better health state evaluation effect.

OsSIDP366, a DUF1644 gene, positively regulates responses to drought and salt stresses in rice.

Domain of unknown function 1644 (DUF1644) is a highly conserved amino acid sequence motif present only in plants. Analysis of expression data of the family of DUF1644-containing genes indicated that they may regulate responses to abiotic stress in rice. Here we present our discovery of the role of OsSIDP366, a member of the DUF1644 gene family, in response to drought and salinity stresses in rice. Transgenic rice plants overexpressing OsSIDP366 showed enhanced drought and salinity tolerance and reduced water loss as compared to that in the control, whereas plants with downregulated OsSIDP366 expression levels using RNA interference (RNAi) were more sensitive to salinity and drought treatments. The sensitivity to abscisic acid (ABA) treatment was not changed in OsSIDP366-overexpressing plants, and OsSIDP366 expression was not affected in ABA-deficient mutants. Subcellular localization analysis revealed that OsSIDP366 is presented in the cytoplasmic foci that colocalized with protein markers for both processing bodies (PBs) and stress granules (SGs) in rice protoplasts. Digital gene expression (DGE) profile analysis indicated that stress-related genes such as SNAC1, OsHAK5 and PRs were upregulated in OsSIDP366-overexpressing plants. These results suggest that OsSIDP366 may function as a regulator of the PBs/SGs and positively regulate salt and drought resistance in rice.

Suppression of expression of the putative receptor-like kinase gene NRRB enhances resistance to bacterial leaf streak in rice.

Bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is an important disease of rice, which is responsible for the economic losses worldwide. Functional investigation of differentially expressed protein genes (DEPGs) from rice (Oryza sativa L.) upon Xoc infection provides insight into the molecular mechanism of rice-Xoc interactions. Here, we show that one of DEPGs designated NRRB plays a role in rice-Xoc interactions. NRRB, a receptor-like cytoplasmic kinase gene was preferentially expressed in leaf blades and leaf sheaths where the pathogen colonized. Its transcription was depressed by two defense-signal compounds salicylic acid and 1-aminocyclopropane-1-carboxylic-acid, but was activated by wounding and abscisic acid. Additionally, a plenty of cis-elements associated with stress responses were discovered in the promoter region of NRRB. These data suggest that NRRB is involved in stress responses. More importantly, the NRRB-suppressing rice plants exhibited enhanced resistance against BLS, with the markedly shorter average lesion length than that of the wild type. Furthermore, transcription of some salicylic acid synthesis-related and pathogenesis-related genes including PAD4, PR1a and WRKY13 in transgenic plants was activated, implying that enhanced resistance to BLS might be mediated by the activation of the SA signaling pathway. In conclusion, NRRB gene is involved in various stress responses and regulating resistance to BLS, therefore it might be one of useful genes for rice improvement in future.

Overexpression of a new stress-repressive gene OsDSR2 encoding a protein with a DUF966 domain increases salt and simulated drought stress sensitivities and reduces ABA sensitivity in rice.

Domain of Unknown Function 966 (DUF966) gene family was found in the protein family database, which consisted of seven genes in rice. The proteins encoded by these genes contained one or two highly conserved DUF966 domains. The available data of public microarray databases implied that these genes might play crucial roles in plant response to abiotic stresses. In this study, a member of the DUF966 gene family, DUF966-stress repressive gene 2 in Oryza sativa (OsDSR2, Loc_Os01g62200), was cloned and its role in rice responding to salt and simulated drought stresses was functionally characterized. OsDSR2 was expressed mainly in nodes of stems and leaf blades from rice. Expression profile analysis of adversity showed that OsDSR2 had different transcriptional responses to salt, drought, cold, heat and oxidative (H2O2) stresses, as well as abscisic acid (ABA), methyl jasmonate, salicylic acid, gibberellin acid and auxin treatments. Transient expression demonstrated that OsDSR2 was localized in the membrane and nucleus. Overexpression of OsDSR2 could increase salt and simulated drought (polyethyleneglycol)-stress sensitivities in rice by downregulating the expression of ABA- and stress-responsive genes including OsNCED4, SNAC1, OsbZIP23, P5CS, Oslea3 and rab16C. Furthermore, OsDSR2-overexpressing plants showed reduced ABA sensitivity during the post-germination stage. These results suggested that OsDSR2 negatively regulated rice response to salt and simulated drought stresses as well as ABA signaling, which provided some useful data for understanding the functional roles of DUF966 family genes in abiotic stress responses in plants.

Over-expression in the nucleotide-binding site-leucine rich repeat gene DEPG1 increases susceptibility to bacterial leaf streak disease in transgenic rice plants.

Bacterial leaf streak of rice (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is a widely-spread disease in the main rice-producing areas of the world. Investigating the genes that play roles in rice-Xoc interactions helps us to understand the defense signaling pathway in rice. Here we report a differentially expressed protein gene (DEPG1), which regulates susceptibility to BLS. DEPG1 is a nucleotide-binding site (NBS)-leucine rich repeat (LRR) gene, and the deduced protein sequence of DEPG1 has approximately 64% identity with that of the disease resistance gene Pi37. Phylogenetic analysis of DEPG1 and the 18 characterized NBS-LRR genes revealed that DEPG1 is more closely related to Pi37. DEPG1 protein is located to the cytoplasm, which was confirmed by transient expression of DEPG1-GFP (green fluorescent protein) fusion construct in onion epidermal cells. Semi-quantitative PCR assays showed that DEPG1 is widely expressed in rice, and is preferentially expressed in internodes, leaf blades, leaf sheaths and flag leaves. Observation of cross sections of leaves from the transgenic plants with a DEPG1-promoter::glucuronidase (GUS) fusion gene revealed that DEPG1 is also highly expressed in mesophyll tissues where Xoc mainly colonizes. Additionally, Xoc negatively regulates expression of DEPG1 at the early stage of the pathogen infection, and so do the three defense-signal compounds including salicylic acid (SA), methyl jasmonate (MeJA) and 1-aminocyclopropane-1-carboxylic-acid (ACC). Transgenic rice plants overexpressing DEPG1 exhibit enhanced susceptibility to Xoc compared to the wild-type controls. Moreover, enhanced susceptibility to Xoc may be mediated by inhibition of the expression of some SA biosynthesis-related genes and pathogenesis-related genes that may contribute to the disease resistance. Taken together, DEPG1 plays roles in the interactions between rice and BLS pathogen Xoc.

Extended GTST-MLD for aerospace system safety analysis.

The hazards caused by complex interactions in the aerospace system have become a problem that urgently needs to be settled. This article introduces a method for aerospace system hazard interaction identification based on extended GTST-MLD (goal tree-success tree-master logic diagram) during the design stage. GTST-MLD is a functional modeling framework with a simple architecture. Ontology is used to extend the ability of system interaction description in GTST-MLD by adding the system design knowledge and the past accident experience. From the level of functionality and equipment, respectively, this approach can help the technician detect potential hazard interactions. Finally, a case is used to show the method.

OsSIDP301, a Member of the DUF1644 Family, Negatively Regulates Salt Stress and Grain Size in Rice.

As a major environmental factor, salt stress substantially retards growth and reduces the productivity of rice (Oryza sativa). Members of the DUF1644 family, "the domains of unknown function 1644 motif" are predicted to play an essential regulatory role in response to abiotic stress. However, the specific molecular mechanisms of most members of this family remain elusive. Here, we report that the OsSIDP301 (stress-induced DUF1644 protein) was induced by salt stress and abscisic acid (ABA). We found that overexpression of OsSIDP301 (OE) in plants conferred salt hypersensitivity and reduced grain size, whereas plants with OsSIDP301 RNA interference (RNAi) exhibited salt tolerance and increased grain size in rice. OsSIDP301 determines salt stress tolerance by modulating genes involved in the salt-response and ABA signaling pathways. Further studies suggest that OsSIDP301 regulates grain size by influencing cell expansion in spikelet hulls. Moreover, OsSIDP301 interacts with OsBUL1 COMPLEX1 (OsBC1), which positively regulates grain size in rice. Our findings reveal that OsSIDP301 functions as a negative regulator of salt stress and grain size, and repressing its expression represents a promising strategy for improving salt stress tolerance and yield in rice.

RNA Binding Protein OsTZF7 Traffics Between the Nucleus and Processing Bodies/Stress Granules and Positively Regulates Drought Stress in Rice.

Tandem CCCH zinc finger (TZF) proteins are the essential components of processing bodies (PBs) and stress granules (SGs), which play critical roles in growth development and stress response in both animals and plants through posttranscriptional regulation of target mRNA. In this study, we characterized the biological and molecular functions of a novel tandem zinc finger protein, OsTZF7. The expression of OsTZF7 was upregulated by abiotic stresses, including polyethylene glycol (PEG) 4000, NaCl, and abscisic acid (ABA) in rice. Accordingly, the overexpression of OsTZF7 increased drought tolerance and enhanced sensitivity to exogenous ABA in rice, whereas the knockdown of OsTZF7 resulted in the opposite phenotype. RNA-seq analysis revealed that genes related to "response to stress," "abscisic acid signaling," "methylated histone binding," and "cytoplasmic mRNA processing body" are regulated by OsTZF7. We demonstrated that OsTZF7 can traffic between the nucleus and PBs/SGs, and the leucine-rich nuclear export signal (NES) mediates the nuclear export of OsTZF7. Additionally, we revealed that OsTZF7 can bind adenine- and uridine-rich (AU-rich) element (ARE) or ARE-like motifs within the 3' untranslated region of downregulated mRNAs, and interact with PWWP family proteins in vitro. Together, these results indicate that OsTZF7 positively regulates drought response in rice via ABA signaling and may be involved in mRNA turnover.