A field experiment was conducted to evaluate the combined or individual effects of biochar and nitrapyrin (a nitrification inhibitor) on N
2
O and NO emissions from a sandy loam soil cropped to ...maize. The study included nine treatments: addition of urea alone or combined with nitrapyrin to soils that had been amended with biochar at 0, 3, 6, and 12 t ha
−1
in the preceding year, and a control without the addition of N fertilizer. Peaks in N
2
O and NO flux occurred simultaneously following fertilizer application and intense rainfall events, and the peak of NO flux was much higher than that of N
2
O following application of basal fertilizer. Mean emission ratios of NO/N
2
O ranged from 1.11 to 1.72, suggesting that N
2
O was primarily derived from nitrification. Cumulative N
2
O and NO emissions were 1.00 kg N
2
O-N ha
−1
and 1.39 kg NO-N ha
−1
in the N treatment, respectively, decreasing to 0.81–0.85 kg N
2
O-N ha
−1
and 1.31–1.35 kg NO-N ha
−1
in the biochar amended soils, respectively, while there was no significant difference among the treatments. NO emissions were significantly lower in the nitrapyrin treatments than in the N fertilization-alone treatments (
P
< 0.05), but there was no effect on N
2
O emissions. Neither biochar nor nitrapyrin amendment affected maize yield or N uptake. Overall, our results showed that biochar amendment in the preceding year had little effect on N
2
O and NO emissions in the following year, while the nitrapyrin decreased NO, but not N
2
O emissions, probably due to suppression of denitrification caused by the low soil moisture content.
A
15
N tracing incubation study was carried out using a sandy loam soil without (control) and with field-aged biochar (biochar) to investigate the mechanisms underlying the effects of field-aged ...biochar on nitrous oxide (N
2
O) emissions. During the incubation, carried out at 40%, 60%, and 80% water-filled pore space (WFPS), cumulative N
2
O emission decreased from 24.13–26.40 μg N kg
−1
in the control soil to 18.27–23.94 μg N kg
−1
in the biochar soil, with a reduction of 9.3–24.3%. The contribution of autotrophic nitrification to total N
2
O production was 81.8–87.6% in the control soil under 40–80% WFPS, which was significantly reduced by field-aged biochar to 67.1–78.6%. Under 60% WFPS, the gross rates of autotrophic nitrification and gross mineralization were reduced from 11.95 and 4.43 μg N g
−1
d
−1
, respectively, in the control soil to 7.32 and 0.60 μg N g
−1
d
−1
, respectively, in the biochar soil. The field-aged biochar increased the NH
4
+
immobilization rate by 440%, primarily by immobilizing NH
4
+
into the recalcitrant organic N pool. Both the turnover rate of NH
4
+
mineralization-immobilization and the ratio of nitrification to NH
4
+
immobilization were reduced under biochar amendment, consequently lowering the supply of NH
4
+
for nitrifiers. In addition, compared with the control soil, the gross rate of NH
4
+
adsorption was significantly higher in the biochar soil. Taken together, our results suggest that field-aged biochar contributes to mitigating N
2
O emissions, primarily by decreasing the autotrophic nitrification rate through a reduced NH
4
+
supply due to increased mineral N immobilization and adsorption and lowered organic N mineralization.
Pathogenic fungi including Penicillium digitatum and Penicillium italicum are the main destructive pathogens in the citrus industry, causing great losses during postharvest process. To our knowledge, ...only one mycovirus from P. digitatum has been reported, and the prevalence of such mycoviruses against citrus postharvest pathogenic fungi and their genotyping were still under investigation. In the present study, we showed that 39 of 152 Penicillium isolates from main citrus-growing areas in China were infected with various mycoviruses belonging to polymycoviruses, Narna-like viruses, and families Totiviridae, Partitivirdae and Chrysoviridae. The next generation sequencing (NGS) towards virus genome library and the following molecular analysis revealed two novel mycoviruses Penicillium digitatum polymycovirus 1 (PdPmV1) and Penicillium digitatum Narna-like virus 1 (PdNLV1), coexisting in P. digitatum strain HS-RH2. The fungicide-resistant P. digitatum strains HS-F6 and HS-E9 coinfected by PdPmV1 and PdNLV1 exhibited obvious reduction in triazole drug prochloraz resistance by mycelial growth analysis on both PDA plates and citrus fruit epidermis with given prochloraz concentration. This report at the first time characterized two novel mycoviruses from P. digitatum and revealed the mycovirus-induced reduction of fungicide resistance.
Cellulose is the most abundant polysaccharide in plant biomass and an important precursor of soil organic matter formation. Fungi play a key role in carbon cycling dynamics because they tend to ...decompose recalcitrant materials. Here, we applied
Ccellulose and
Ccellulose to distinguish the effects of application of compost, nitrogen-phosphorus-potassium (NPK) fertilizer, and no fertilizer (control) for 27 years upon cellulose decomposition via RNA-based stable isotope probing (RNA-SIP). The loss ratio of added cellulose C in compost soil was 67.6 to 106.7% higher than in NPK and control soils during their 20-day incubation.
(mainly members of the genus Cryptococcus) dominated cellulose utilization in compost soil, whereas the copiotrophic
were more abundant in NPK and unfertilized soils. Compared with NPK and control soils, compost application increased the diversity of
C-assimilating fungi. The
C-labeled fungal communities in compost soil were more phylogenetically clustered and exhibited greater species relatedness than those in NPK and control soils, perhaps because of stringent filtering of narrow-spectrum organic resources and biological invasion originating from added compost. These changes led to an augmented decomposition capacity of fungal species for cellulose-rich substrates and reduced cellulose C sequestration efficiency. The RNA-SIP technique is more sensitive to responses of fungi to altered soil resource availability than DNA-SIP. Overall, long-term compost application modified fungal community composition and promoted fungal diversity and phylogenetic relatedness, accelerating the decomposition of substrate cellulose in soil. This work also highlights the RNA-SIP technique's value for comprehensively assessing the contributions of active fungi to the substrate decomposition process.
Cellulose is a very rich component in plant biomass and an important precursor of soil organic matter formation. Fungal communities are known to be important drivers of organic carbon accumulation in arable soils. However, current understanding of responses of fungal species to cellulose amendment and the contributions of active fungi to substrate decomposition process is still very superficial. Here, we established a
Ccellulose microcosm experiment with soils subjected to long-term application of compost, nitrogen-phosphorus-potassium (NPK) fertilizer, and no fertilizer (control). The novel
C-RNA-SIP technique with subsequent high-throughput sequencing was used to investigate the linkages between active fungal taxa and cellulose decomposition. Our study demonstrated that
dominated cellulose utilization in compost soil, whereas the copiotrophic
were more enriched in both NPK and unfertilized soils. We also found that the compost amendment promoted fungal diversity and phylogenetic relatedness and strengthened the decomposition capacity of fungi for cellulose-rich substrates by enhancing synergistic interactions, thereby reducing cellulose C sequestration efficiency. Overall, our research has implications for our understanding of the role of active fungi in cellulose C transformation in soils undergoing different types of long-term nutrient management.
Introduction
Brachiaria humidicola
, a tropical grass, could release root exudates with biological nitrification inhibition (BNI) capacity and reduce soil nitrous oxide (N
2
O) emissions from ...grasslands. However, evidence of the reduction effect
in situ
in tropical grasslands in China is lacking.
Methods
To evaluate the potential effects of
B
.
humidicola
on soil N
2
O emissions, a 2-year (2015–2017) field experiment was established in a Latosol and included eight treatments, consisting of two pastures, non-native
B
.
humidicola
and a native grass,
Eremochloa ophiuroide
, with four nitrogen (N) application rates. The annual urea application rates were 0, 150, 300, and 450 kg N ha
−1
.
Results
The average 2-year
E
.
ophiuroides
biomass with and without N fertilization were 9.07–11.45 and 7.34 t ha
−1
, respectively, and corresponding values for
B
.
humidicola
increased to 31.97–39.07 and 29.54 t ha
−1
, respectively. The N-use efficiencies under
E
.
ophiuroide
and
B
.
humidicola
cultivation were 9.3–12.0 and 35.5–39.4%, respectively. Annual N
2
O emissions in the
E
.
ophiuroides
and
B
.
humidicola
fields were 1.37 and 2.83 kg N
2
O-N ha
−1
, respectively, under no N fertilization, and 1.54–3.46 and 4.30–7.19 kg N
2
O-N ha
−1
, respectively, under N fertilization.
Discussions
According to the results,
B
.
humidicola
cultivation increased soil N
2
O emissions, especially under N fertilization. This is because
B
.
humidicola
exhibited the more effective stimulation effect on N
2
O production
via
denitrification primarily due to increased soil organic carbon and exudates than the inhibition effect on N
2
O production
via
autotrophic nitrification. Annual yield-scaled N
2
O emissions in the
B
.
humidicola
treatment were 93.02–183.12 mg N
2
O-N kg
−1
biomass, which were significantly lower than those in the
E
.
ophiuroides
treatment. Overall, our results suggest that cultivation of the non-native grass,
B
.
humidicola
with BNI capacity, increased soil N
2
O emissions, while decreasing yield-scaled N
2
O emissions, when compared with native grass cultivation.
Heat shock proteins (HSPs) are a protein family that respond to physiological stress, such as heat, starvation, and infection. As cellular protein chaperones, they play an important role in protein ...folding, assembly, and degradation. Though it is well known that HSP27 is involved in a range of viral infections, its role during an encephalomyocarditis virus (EMCV) infection is not known. Here, we report that EMCV degrades HSP27 and that EMCV proteins 2C
and 3A
are primarily responsible for its degradation. Consequently, loss of cellular HSP27 augmented EMCV proliferation, an effect that could be reversed upon HSP27 overexpression. Importantly, we found that HSP27 positively regulated EMCV-triggered type I interferon (IFN) production. Moreover, overexpression of 2C
and 3A
significantly blocked type I IFN production. We also found for the first time that HSP27, as a molecular chaperone, can specifically interact with MDA5 and stabilize the expression of MDA5. Collectively, this study shows that HSP27 dampens EMCV infectivity by positively regulating EMCV-triggered retinoic acid-inducible gene (RIG)-I-like receptor (RLR)/melanoma differentiation-associated gene 5 (MDA5) signal pathway, while EMCV proteins 2C
and 3A
interact with HSP27 and degrade HSP27 protein expression to allow EMCV proliferation. Our findings provide further mechanistic evidence for EMCV partaking in immune escape mechanisms, and that 2C
and 3A
could serve as potential antiviral targets.
Multiple object tracking based on tracking-by-detection is the most common method used in addressing illumination change and occlusion problems. In this paper, we present a tracking algorithm based ...on Edge Multi-channel Gradient Model. We first use the canny operator to extract the edges of the image, and establish a biologically inspired Multi-channel Gradient Model that integrate the spatio-temporal-spectral information of the edge to detect moving multiple objects. Under this model, the ORB feature is introduced to solve the problem of matching the object with the object library. Therefore, we can achieve object consistency, and the threshold classification method can solve the problem of multiple object occlusion in the process of persistent multiple object tracking. The experimental results show that the proposed method can effectively deal with the problems of occlusion and illumination changes. Compared with other state-of-the-art algorithms, the proposed algorithm achieves better performance on MOTA, MOTP, and IDF1. In particular, it performs best on IDSW on MOT2015 dataset, with an average improvement ratio of 28.99% over the second-place algorithm. In addition, our algorithm has a better performance in running time, achieving a good compromise between the speed and the accuracy.
Cold seeps occur in continental margins worldwide and are deep-sea oases. Anaerobic oxidation of methane is an important microbial process in the cold seeps and plays an important role in regulating ...methane content. This study elucidates the diversity and potential activities of major microbial groups in dependent anaerobic methane oxidation and sulfate-dependent anaerobic methane oxidation processes and provides direct evidence for the occurrence of nitrate-/nitrite-dependent anaerobic methane oxidation (Nr-/N-DAMO) as a previously overlooked microbial methane sink in the hydrate-bearing sediments of the South China Sea. This study provides direct evidence for occurrence of Nr-/N-DAMO as an important methane sink in the deep-sea cold seeps.
Pseudorabies (PR) is a domestic and wild animal infectious disease caused by the pseudorabies virus (PRV) and is one of the major infectious diseases that endanger the global swine industry. Studies ...have reported that PRV may achieve cross-species transmission from pigs to humans in recent years. Therefore, in-depth exploration of the relationship between PRV and host proteins is of great significance for elucidating the pathogenic mechanism of PRV and anti-PRV infection. Here, we report that heat shock protein 27 (HSP27) ubiquitinates and degrades cyclic GMP-AMP synthase (cGAS) and attenuates cGAS-mediated antiviral responses, thereby promoting PRV infection. Overexpression of HSP27 promoted PRV proliferation in vitro, while knockdown of HSP27 inhibited PRV infection. Importantly, we found that HSP27 inhibited PRV infection or poly(dA:dT)-activated IFN-β expression. Further studies found that HSP27 may inhibit cGAS-STING-mediated IFN-β expression through targeting cGAS. In addition, we found that HSP27 can suppress the expression of endogenous cGAS in different cells at both gene transcription and protein expression levels, and that HSP27 interacts with and ubiquitinates cGAS. In conclusion, we reveal for the first time that HSP27 is a novel negative regulator of the cGAS-STING signaling pathway induced by PRV infection or poly(dA:dT) activation and demonstrate that HSP27 plays a crucial role in PRV infection.
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