Summary
Nitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral ...environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavour in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the rice NIN‐like protein 4 (OsNLP4) significantly improves the rice NUE and yield. Field trials consistently showed that loss‐of‐OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signalling genes by directly binding to the nitrate‐responsive cis‐element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 plays a pivotal role in rice NUE and sheds light on crop NUE improvement.
Nitrogen is essential for plant survival and growth. Excessive application of nitrogenous fertilizer has generated serious environment pollution and increased production cost in agriculture. To deal ...with this problem, tremendous efforts have been invested worldwide to increase the nitrogen use ability of crops. However, only limited success has been achieved to date. Here we report that NLP7 (NIN-LIKE PROTEIN 7) is a potential candidate to improve plant nitrogen use ability. When overexpressed in Arabidopsis, NLP7 increases plant biomass under both nitrogen-poor and -rich conditions with better-developed root system and reduced shoot/root ratio. NLP7-overexpressing plants show a significant increase in key nitrogen metabolites, nitrogen uptake, total nitrogen content, and expression levels of genes involved in nitrogen assimilation and signalling. More importantly, overexpression of NLP7 also enhances photosynthesis rate and carbon assimilation, whereas knockout of NLP7 impaired both nitrogen and carbon assimilation. In addition, NLP7 improves plant growth and nitrogen use in transgenic tobacco (Nicotiana tabacum). Our results demonstrate that NLP7 significantly improves plant growth under both nitrogen-poor and -rich conditions by coordinately enhancing nitrogen and carbon assimilation and sheds light on crop improvement.
Nitrogen (N) is an essential macronutrient for crop growth and yield. Improving the N use efficiency (NUE) of crops is important to agriculture. However, the molecular mechanisms underlying NUE ...regulation remain largely elusive. Here we report that the OsNLP3 (NIN‐like protein 3) regulates NUE and grain yield in rice under N sufficient conditions. OsNLP3 transcript level is significantly induced by N starvation and its protein nucleocytosolic shuttling is specifically regulated by nitrate. Loss‐of‐function of OsNLP3 reduces plant growth, grain yield, and NUE under sufficient nitrate conditions, whereas under low nitrate or different ammonium conditions, osnlp3 mutants show no clear difference from the wild type. Importantly, under sufficient N conditions in the field, OsNLP3 overexpression lines display improved grain yield and NUE compared with the wild type. OsNLP3 orchestrates the expression of multiple N uptake and assimilation genes by directly binding to the nitrate‐responsive cis‐elements in their promoters. Overall, our study demonstrates that OsNLP3, together with OsNLP1 and OsNLP4, plays overlapping and differential roles in N acquisition and NUE, and modulates NUE and the grain yield increase promoted by N fertilizer. Therefore, OsNLP3 is a promising candidate gene for the genetic improvement of grain yield and NUE in rice.
Summary Statement
Crop nitrogen use efficiency (NUE) is an important agronomic trait. But the molecular mechanisms underlying NUE regulation are not well understood. This study reveals that rice NIN‐like protein 3 (OsNLP3) regulates NUE and grain yield especially under N sufficient conditions and is a promising candidate gene for improving grain yield and NUE in rice.
Bacterium A1, isolated to enhance nitrogen removal from ammonium-rich wastewater
in situ, exhibited an amazing ability to convert ammonium to gaseous nitrogen compounds under fully aerobic ...conditions, while growing autotrophically or heterotrophically. A1 was identified as
Bacillus subtilis by morphological and physiological characteristics, and phylogenetic analysis of its 16S rDNA gene sequence. Nitrogen removal by A1 was analyzed in relation to the ammonium concentration, presence of organic carbon, carbon source, and carbon-to-nitrogen ratio (C/N). The nitrogen balance during 120
h of autotrophic growth in the presence of 104.12
±
1.27
mg/L
NH
4
+
N
showed that 20.4
±
2.7% of
NH
4
+
N
was removed as gaseous nitrogen compounds, and
A1 removed 58.4
±
4.3% of
NH
4
+
N
within 60
h of growth in acetate medium at a C/N
of 6. A mean ammonium removal rate of 3.52
mg
NH
4
+
N
/(L
h) was achieved in an open wastewater system, indicating great potential of A1 for future full-scale applications.
After the impoundment of the Three Gorges Reservoir, some huge ancient landslides were reactivated and deformed, showing typical hydrodynamic pressure landslide characteristics. The Baishuihe ...landslide was a typical hydrodynamic pressure landslide. The management department conducted slope cutting treatments from 2018 to 2019. To evaluate the treatment effect of rear slope cutting, this study analyzed the data of the surface deformation survey and field monitoring over the past 20 years and the characteristics of the reservoir water-triggered Baishuihe landslide deformation, and calculated the seepage field, displacement field, and stability coefficient before and after landslide treatment. The results showed that the deformation of the Baishuihe landslide was primarily related to a decrease in the reservoir water level. Owing to the poor permeability of the landslide soil, the decrease in the reservoir water level produced a seepage force pointing to the outside of the landslide body, leading to the step deformation of the landslide displacement. The landslide was treated by rear slope cutting, and the “step” deformation of the landslide disappeared after treatment. The hydrodynamic pressure caused by the change in reservoir water after cutting the slope did not disappear. However, as the slope cutting greatly reduced the overall sliding force of the landslide, its stability was greatly improved. Notably, high stability can still be ensured under extreme rainfall after treatment. Slope cutting is effective for treating hydrodynamic pressure landslides. This study can provide effective technical support for the treatment of reservoir landslides.
A novel phenanthrene （PHE）-degrading strain named as Sphingomonas sp. GF2B was isolated and identified from a farmland soil. Effects of a synthetic surfactant （Tween-80） and a rhamnolipid ...biosurfactant on PHE degradation by Sphingomonas sp. GF2B were investigated at different concentrations of the surfactants. The results showed that Sphingomonas sp. GF2B was able to mineralize up to 83.6% of PHE within 10 days without addition of surfactants. The addition of Tween-80 to the reaction medium inhibited greatly PHE biodegradation, with only 33.5% of PHE degraded. However, the biosurfactant facilitated PHE biodegradation. with up to 99.5% of PHE degraded. The preferential utilization of PHE as a carbon source and the enhanced solubility of PHE by the biosurfactant were likely responsible for the higher biodegra- dation efficiency of PHE in the presence of the biosurfactant. Therefore, it could be concluded that the application of the biosurfactant to PHE-contaminated soils was perhaps a feasible way to facilitate the PHE biodegradation.
Bioleaching of Cr（Ⅲ） from tannery sludge using the mixture of ingenuous iron- and sulfur-oxidizing bacteria was investigated in batch flasks. Experiments involved the adaptation of indigenous ...iron-and sulfur-oxidizing bacteria, the pre-acidification the sludge to pH 6.0 and the addition of energy substrates. Results showed the inoculation of mixture of ingenuous iron- and sulfur-oxidizing bacteria and co-addition of Fe^2 and elemental sulfur accelerated acid production and increase of oxidation-reduction potential originating from the bio-oxidation of Fe2^＋ and elemental sulfur. Dissolved Cr concentration increased concomitant with pH decreased in the sludge and reached its maximum removal of 95.6%. The amelioration of the odor of bioleached sludge could be noted. However, 20.4%o of N, 24.5% of P and 14.3% of organic matter were lost in the bioleaching process. The residual Cr content in the leached tannery sludge was acceptable for use in agriculture. This study had shown the feasibility of applying the bioleaching process, developed for sewage sludge, to tannery sludge with high Cr.
An environmental trace gases monitoring instrument (EMI) is a nadir-viewing
wide-field imaging spectrometer, which aims to quantify the global
distribution of tropospheric and stratospheric trace ...gases, and is planned to
be launched on 9 May 2018. The selected wavelength bands for EMI are
ultraviolet channels: UV1 (240–315 nm), UV2 (311–403 nm) and visible
channels: VIS1 (401–550 nm), and VIS2 (545–710 nm). The spectral resolution
is 0.3–0.5 nm, and the swath is approximately 114∘ wide to achieve
a one-day global coverage. The preflight calibration of the EMI is discussed
in this paper. A tunable laser and rotating platform are adopted for an EMI
wavelength calibration of the entire field of view. The accuracy of the
wavelength calibration is less than 0.05 nm. In addition, the solar
calibration mode shows the same results compared with Earth observation mode.
A thermal vacuum test is performed to investigate the influence of in-orbit
thermal vacuum conditions on the EMI, and EMI spectral response changes with
pressure, optical bench temperature, and charge-coupled device (CCD) detector
temperature are obtained. For a radiometric calibration of UV1, a diffuser
plate with a 1000 W xenon lamp, which produces sufficient UV output, is
selected. An integrating sphere system with tungsten halogen lamp is selected
for the UV2, VIS1, and VIS2. The accuracies of radiance calibration are
4.53 % (UV1), 4.52 % (UV2), 4.31 % (VIS1), and 4.30 % (VIS2). The
goniometry correction factor and irradiance response coefficient of the EMI
are also calibrated on the ground for an in-orbit calibration of the solar. A
signal-to-noise ratio (SNR) model of the EMI is introduced, and the EMI
in-orbit SNR is estimated using the SNR and MODTRAN radiance
models.
The specific binding of N7-methylguanine cap analogues to the RNA methyltransferase VP39 was observed through X-ray crystallography, providing a prototypical structure for a complex between a protein ...and an mRNA 5' cap.
Apply large general-purpose finite element analysis software ABAQUS as a platform, The criterion of iteration non-convergence conventionally used for assessing the instability state of slopes,and an ...example is given to the following conclusions: The strength reduction method based on ABAQUS simulate anti-slide pile slope stability analysis that has a true reflection of the elastic-plastic deformation in geotechnical engineering,it can be widely used in elastic-plastic deformation problems in geotechnical engineering. The anti-slide pile can effectively improve the stability of slopes, setting up anti-slide pile egitimately in the soil plays an important role at the safety of slope stability.
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