A new species of Passaloecus Shuckard (Hymenoptera, Crabronidae) from China, with a key to Oriental species.

A new species of Passaloecus Shuckard, P.birugatus Bashir & Chen, sp. nov., is described and illustrated from Yunnan Province, China. The new species can be easily distinguished from known species of Passaloecus by its very long petiole, which is distinctly longer than wide, obscure scrobal suture, propodeum rugae and striations, body punctation, and coloration. An identification key to the Oriental species of Passaloecus is given.

Overexpression of abscisic acid-insensitive gene ABI4 from Medicago truncatula, which could interact with ABA2, improved plant cold tolerance mediated by ABA signaling.

ABI4 is considered an important transcription factor with multiple regulatory functions involved in many biological events. However, its role in abiotic stresses, especially low-temperature-induced stress, is poorly understood. In this study, the MtABI4 gene was derived from M. truncatula, a widely used forage grass. Analysis of subcellular localization indicated that ABI4 was localized in the nucleus. Identification of expression characteristics showed that ABI4 was involved in the regulatory mechanisms of multiple hormones and could be induced by the low temperature. IP-MS assay revealed that MtABI4 protein could interact with xanthoxin dehydrogenase protein (ABA2). The two-hybrid yeast assay and the biomolecular fluorescence complementarity assay further supported this finding. Expression analysis demonstrated that overexpression of MtABI4 induced an increase in ABA2 gene expression both in M. truncatula and Arabidopsis, which in turn increased the ABA level in transgenic plants. In addition, the transgenic lines with the overexpression of MtABI4 exhibited enhanced tolerance to low temperature, including lower malondialdehyde content, electrical conductivity, and cell membrane permeability, compared with the wide-type lines after being cultivated for 5 days in 4°C. Gene expression and enzyme activities of the antioxidant system assay revealed the increased activities of SOD, CAT, MDHAR, and GR, and higher ASA/DHA ratio and GSH/GSSG ratio in transgenic lines. Additionally, overexpression of ABI4 also induced the expression of members of the Inducer of CBF expression genes (ICEs)-C-repeat binding transcription factor genes(CBFs)-Cold regulated genes (CORs) low-temperature response module. In summary, under low-temperature conditions, overexpression of ABI4 could enhance the content of endogenous ABA in plants through interactions with ABA2, which in turn reduced low-temperature damage in plants. This provides a new perspective for further understanding the molecular regulatory mechanism of plant response to low temperature and the improvement of plant cold tolerance.

Expression of a Hydroxycinnamoyl-CoA Shikimate/Quinate Hydroxycinnamoyl Transferase 4 Gene from Zoysia japonica (ZjHCT4) Causes Excessive Elongation and Lignin Composition Changes in Agrostis stolonifera.

Hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT) is considered to be an essential enzyme for regulating the biosynthesis and composition of lignin. To investigate the properties and function of ZjHCT4, the ZjHCT4 gene was cloned from Zoysia japonica with a completed coding sequence of 1284-bp in length, encoding 428 amino acids. The ZjHCT4 gene promoter has several methyl jasmonate (MeJA) response elements. According to analysis of expression patterns, it was up-regulated by MeJA, GA3 (Gibberellin), and SA (Salicylic acid), and down-regulated by ABA (Abscisic acid). Ectopic ZjHCT4 expression in creeping bentgrass causes excessive plant elongation. In addition, the content of G-lingnin and H-lingnin fell in transgenic plants, whereas the level of S-lingnin increased, resulting in a considerable rise in the S/G unit ratio. Analysis of the expression levels of lignin-related genes revealed that the ectopic expression of ZjHCT4 altered the expression levels of a number of genes involved in the lignin synthesis pathway. Simultaneously, MeJA, SA, GA3, IAA, BR (Brassinosteroid), and other hormones were dramatically enhanced in transgenic plants relative to control plants, whereas ABA concentration was significantly decreased. Expression of ZjHCT4 impacted lignin composition and plant growth via altering the phenylpropionic acid metabolic pathway and hormone response, as revealed by transcriptome analysis. HCTs may influence plant lignin composition and plant development by altering hormone content. These findings contributed to a deeper comprehension of the lignin synthesis pathway and set the stage for further investigation and application of the HCTs gene.

Expression of a Chlorophyll b Reductase Gene from Zoysia japonica Causes Changes in Leaf Color and Chlorophyll Morphology in Agrostis stolonifera.

The NYC-like (NOL) enzyme is considered as an essential enzyme for chlorophyll b degradation, which catalyzes the formation of 7-hydroxymethyl chlorophyll a from chlorophyll b. The ZjNOL gene was cloned from Zoysia japonica with a completed coding sequence of 981-bp in length, encoding 326 amino acids. ZjNOL was localized on the stroma side of the thylakoid membrane, and co-localized with ZjNYC in the chloroplasts. Multiple photoregulatory elements and hormone regulatory elements were identified in the promoter region of the ZjNOL gene, and the expression level of the ZjNOL gene was dramatically up-regulated in senescence leaves, which were regulated by a variety of plant hormones. ZjNOL's ectopic expression in creeping bentgrass produced yellow leaves, thicker cortex, and smaller vascular column cells. Additionally, transgenic plants exhibited morphological alterations in their chloroplast structure, and the number of grana and thylakoids per grana stack reduced dramatically. Transgenic plants also had a lower photosynthetic rate and Fm/Fv than the control. The transgenic plants displayed a decreased chlorophyll content and a greater rate of ion leakage. The properties and activities of ZjNOL will serve as a foundation for future research into gene functions and regulatory processes.

Transcriptome profiling revealed candidate genes, pathways and transcription factors related to nitrogen utilization and excessive nitrogen stress in perennial ryegrass.

Ryegrass (Lolium perenne L.), a high-quality forage grass, is a good nutrient source for herbivorous livestock. However, improving nitrogen use efficiency and avoiding nitrate toxicity caused by excessive nitrogen are continual challenges in ryegrass production. The molecular mechanism underlying the response of ryegrass to nitrogen, especially excessive nitrogen, remains unclear. In this study, the transcriptomic changes under different nitrogen levels were investigated in perennial ryegrass by high-throughput next-generation RNA sequencing. Phenotypic characterization showed that treatment with half of the standard N concentration (N0.5) led to a better growth state than the other three treatments. The treatments with the standard N concentration (N1) and treatments with ten times higher than the standard N concentration (N10) contained excessive nitrogen, which placed stress on plant growth. Analysis of differentially expressed genes indicated that 345 and 104 genes are involved in the regulation of nitrogen utilization and excessive nitrogen stress, respectively. KEGG enrichment analysis suggested that "photosynthesis-antenna proteins" may respond positively to appropriate nitrogen conditions, whereas "steroid biosynthesis", "carotenoid biosynthesis" and "C5-branched dibasic acid metabolism" were identified as the top significantly enriched pathways in response to excessive nitrogen. Additionally, 21 transcription factors (TFs) related to nitrogen utilization were classified into 10 families, especially the AP2-EREBP and MYB TF families. Four TFs related to excessive nitrogen stress were identified, including LOBs, NACs, AP2-EREBPs and HBs. The expression patterns of these selected genes were also analyzed. These results provide new insight into the regulatory mechanism of ryegrass in response to nitrogen utilization and excessive nitrogen stress.

Expression of ZjPSY, a Phytoene Synthase Gene from Zoysia japonica Affects Plant Height and Photosynthetic Pigment Contents.

Phytoene synthase (PSY) is a key limiting enzyme in the carotenoid biosynthesis pathway for regulating phytoene synthesis. In this study, ZjPSY was isolated and identified from Zoysia japonica, an important lawn grass species. ZjPSY cDNA was 1230 bp in length, corresponding to 409 amino acids. ZjPSY showed higher expression in young leaves and was downregulated after GA3, ABA, SA, and MeJA treatments, exhibiting a sensitivity to plant hormones. Regulatory elements of light and plant hormone were found in the upstream of ZjPSY CDS. Expression of ZjPSY in Arabidopsis thaliana protein led to carotenoid accumulation and altered expression of genes involved in the carotenoid pathway. Under no-treatment condition, salt treatment, and drought treatment, transgenic plants exhibited yellowing, dwarfing phenotypes. The carotenoid content of transgenic plants was significantly higher than that of wild-type under salt stress and no-treatment condition. Yeast two-hybrid screening identified a novel interacting partner ZjJ2 (DNAJ homologue 2), which encodes heat-shock protein 40 (HSP40). Taken together, this study suggested that ZjPSY may affect plant height and play an important role in carotenoid synthesis. These results broadened the understanding of carotenoid synthesis pathways and laid a foundation for the exploration and utilization of the PSY gene.

Williamsia soli sp. nov., an actinobacterium isolated from soil at a thermal power plant in Yantai, China.

Strain C17T, a novel strain belonging to the phylum Actinobacteria, was isolated from a thermal power plant in Yantai, Shandong Province, China. Cells of strain C17T were Gram stain positive, aerobic, pink, non-motile and round with neat edges, showing optimum growth at 28 °C. Phylogenetically, strain C17T was a member of the class Actinobacteria, order Mycobacteriales, family Gordoniaceae. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that the related strains were Williamsia faeni JCM 17784 T and Williamsia limnetica KCTC 19981 T with pairwise sequence similarity of 98.5% for both strains. According to the draft genome sequence, the DNA G + C content was 64.7%. The average amino acid identity (AAI), average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between genome sequences of strain C17T and the closest type strain W. faeni JCM 17784 T were 77.5, 77.9, and 20.7%, respectively. Predominant fatty acids were C16:0 (31.7%) and C18:1ω9c (26.8%). The major menaquinone was MK-9. The diagnostic phospholipids were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), and phosphatidylinositol (PI). Therefore, the combined phenotypic, chemotaxonomic and phylogenetic data indicated that strain C17T was considered to represent a novel species of the genus Williamsia. Williamsia soli sp. nov. was proposed for strain C17T (= KCTC 49567 T = MCCC 1K04355T).

Effects of Elevation and Distance from Highway on the Abundance and Community Structure of Bacteria in Soil along Qinghai-Tibet Highway.

In recent years, highway construction in the Qinghai-Tibet Plateau (QTP) has developed rapidly. When the highway passes through grassland, the soil, vegetation, and ecological environment along the line are disturbed. However, the impact on soil bacteria is still unclear. Soil bacteria play an important role in the ecological environment. The Qinghai-Tibet Highway (QTH) was selected as the research object to explore the changes in bacterial community structure, vegetation, soil, and other indicators. The results showed that the highway-related activities increased the degradation of vegetation along the road, significantly changed the physical and chemical properties of soil, and caused heavy metal pollution. These environmental factors affected the diversity and community structure of soil bacteria. This kind of disturbance shows a trend of gradually increasing from near to far from the highway. Gemmatimonas, Terrimonas, Nitrospira and Bacillus are more tolerant to environmental changes along the highway, while Barnesiella, and Blastococcus are more sensitive. The content of nitrate decreased and the content of ammonium nitrogen increased in the disturbed area, increasing the abundance of nitrifying bacteria. Therefore, the main factor of the disturbance of the QTH on the grassland is the decline of soil nutrient content, and the supplement of soil nutrients such as carbon and nitrogen should be taken into account in the process of ecological restoration of grassland along the line.

Rhamphothrips genus-group in China, with description of two new species and two new records (Thysanoptera: Thripidae).

Amalothrips bifurcus sp.n. is described from Southwestern China as the third species of Amalothrips, characterized by the forked sense cone on antennal segments IIIIV. Rhamphothrips yunnanensis sp.n. is described as the second known species of Rhamphothrips in which the male has laterally on the mesosternum one thorn-like seta and one stout shaded seta. Two species, Amalothrips noorazlani Ng and Parexothrips palumai Mound, are newly recorded from China.

Establishment and verification of anthropogenic volatile organic compound emission inventory in a typical coal resource-based city.

A few studies on volatile organic compound (VOC) emission inventories in coal resource-based cities have been reported, and previous emission inventories lacked verification. Herein, using Yangquan as a case study, emission factor (EF) method and "(tracer ratio) TR - positive matrix factorization (PMF)" combined method based on atmospheric data were used to establish and verify the VOC emission inventory in coal resource-based cities, respectively. The total VOC emissions in Yangquan were 9283.2 t [-40.0%, 62.1%] in 2018, with industrial processes being the major contributors. Alkanes (35.8%), aromatics (25.0%), and alkenes (19.8%) were the main compounds in the emission inventory. The verification results for both species emission and source structure were in agreement, indicating the accuracy of VOC emission inventory based on EF method to a certain extent. However, for some species (ethane, propane, benzene, and acetylene), the EF method indicated emissions lower than those obtained from the TR results. Furthermore, the summer-time emission contribution from fossil fuel combustion indicated by the EF method (23.4%) was lower than that obtained from the PMF results (38.4%). Overall, these discrepancies could be attributed to the absence of a coal gangue source in the EF method. The verification results determined the accuracy of the VOC emission inventory and identified existing problems in the estimation of the VOC emission inventory in coal resource-based cities. In particular, not accounting for the coal gangue emissions may result in an underestimation of VOC emissions in coal resource-based cities. Thus, coal gangue emissions should be considered in future research.

Melatonin influences the early growth stage in Zoysia japonica Steud. by regulating plant oxidation and genes of hormones.

Zoysia japonica is a commonly used turfgrass species around the world. Seed germination is a crucial stage in the plant life cycle and is particularly important for turf establishment and management. Experiments have confirmed that melatonin can be a potential regulator signal in seeds. To determine the effect of exogenous melatonin administration and explore the its potential in regulating seed growth, we studied the concentrations of several hormones and performed a transcriptome analysis of zoysia seeds after the application of melatonin. The total antioxidant capacity determination results showed that melatonin treatment could significantly improve the antioxidant capacity of zoysia seeds. The transcriptome analysis indicated that several of the regulatory pathways were involved in antioxidant activity and hormone activity. The hormones concentrations determination results showed that melatonin treatment contributed to decreased levels of cytokinin, abscisic acid and gibberellin in seeds, but had no significant effect on the secretion of auxin in early stages. Melatonin is able to affect the expression of IAA (indoleacetic acid) response genes. In addition, melatonin influences the other hormones by its synergy with other hormones. Transcriptome research in zoysia is helpful for understanding the regulation of melatonin and mechanisms underlying melatonin-mediated developmental processes in zoysia seeds.

[Characteristics and Cause Analysis of Heavy Air Pollution in a Mountainous City During Winter].

Taking the typical heavy air pollution process in Yangquan from December 26, 2018 to January 20, 2019 as an example, the characteristics and cause analysis of heavy air pollution in a mountainous city in winter were analyzed in this study. The results showed that fine particle mass (PM2.5) was the primary pollutant during the heavy pollution period. The water-soluble ions and carbonaceous components were the main components of PM2.5. The secondary ions of SO42-, NO3-, and NH4+ had the lager contribution to water-soluble ions (87.7%), and the secondary organic carbon (SOC) was the main component of the carbonaceous components (71.6%). The concentration of the secondary ions during the heavy pollution period increased by 5.3 times compared to levels before the heavy pollution period, and was an important component resulting in the fast increase of PM2.5. An analysis of meteorological conditions showed that PM2.5 and its main components had a significantly positive relationship with humidity and a significantly negative relationship with wind speed. And that pollution became stronger with an increase in humidity and a decrease in wind speed. The typical meteorological characteristics of mountainous cities are high relative humidity and large temperature variations, which can accelerate the formation of secondary pollutants and are the main reasons for the rapid aggravation of PM2.5. In addition, the lower average wind speed caused by the relatively closed terrain in mountainous cities makes the diffusion conditions of air pollutants relatively poor, which is one of the reasons for the accumulation of pollutants. The source apportionment results showed that the secondary sources (46.0%) were the most important source of PM2.5, followed by coal combustion (32.6%), vehicle exhaust (19.8%), and fugitive dust (1.6%). Therefore, mountainous cities should pay more attention to controlling secondary components, especially secondary ions.

[Characteristics, Source Apportionment, and Environmental Impact of Volatile Organic Compounds in Summer in Yangquan].

Volatile organic compounds (VOCs) were collected at three environmental sampling sites in Yangquan and quantified by gas chromatography-mass selective detector/flame ionization detector(GC-MSD/FID). The VOC sources were identified by diagnostic ratios and positive matrix factorization (PMF), and environmental impact of VOCs on O3 and secondary organic aerosol (SOA) were evaluated. The results showed that the average VOC concentration was (82.1±22.7) µg·m-3, with alkanes being the most abundant group (51.8%), followed by aromatics (17.8%), alkenes (8.0%), and alkynes (3.8%). The diurnal variation of VOCs exhibited a bimodal trend, with twin peaks appearing at 08:00-10:00 and 18:00-20:00, falling to a valley at 12:00-14:00. The results for benzene/toluene (2.1±1.3) and isopentane/n-pentane (1.7±0.6) showed that the ambient VOCs may be influenced by coal combustion and vehicular emissions. Six sources were extracted by PMF:coal combustion (34.9%), vehicle emissions (18.2%), gasoline evaporation (15.2%), industrial emissions (13.6%), biogenic emissions (9.2%), and solvent usage (9.0%). The average concentration of ozone formation potential (OFP) was 156.6 µg·m-3, with the highest contribution from alkenes, while the average concentration of secondary organic aerosol formation potential (SOAp) was 68.7 µg·m-3, mainly from aromatics (93.4%). In summary, coal combustion was the most abundant source of VOCs, and accelerating the management of coal gangue and energy structure readjustment are the key points to address. Meanwhile, restricting the VOCs from vehicle emissions, gasoline evaporation, and industrial emissions is also required.