Theory and experiments support that plant invasions largely impact aboveground biodiversity and function. Yet, much less is known on the influence of plant invasions on the structure and function of ...the soil microbiome of coastal wetlands, one of the largest major reservoirs of biodiversity and carbon on Earth. We studied the continental‐scale invasion of Spartina alterniflora across 2451 km of Chinese coastlines as our model‐system and found that S. alterniflora invasion can largely influence the soil microbiome (across six depths from 0 to 100 cm), compared with the most common microhabitat found before invasion (mudflats, Mud). In detail, S. alterniflora invasion was not only positively associated with bacterial richness but also resulted in important biotic homogenization of bacterial communities, suggesting that plant invasion can lead to important continental scale trade‐offs in the soil microbiome. We found that plant invasion changed the community composition of soil bacterial communities across the soil profile. Moreover, the bacterial communities associated with S. alterniflora invasions where less responsive to climatic changes than those in native Mud microhabitats, suggesting that these new microbial communities might become more dominant under climate change. Plant invasion also resulted in important reductions in the complexity and stability of microbial networks, decoupling the associations between microbes and carbon pools. Taken together, our results indicated that plant invasions can largely influence the microbiome of coastal wetlands at the scale of China, representing the first continental‐scale example on how plant invasions can reshuffle the soil microbiome, with consequences for the myriad of functions that they support.
The continental‐scale invasion of Spartina alterniflora across China’s coastline was used as our model‐system to study the impact of plant invasions on the soil microbiome of blue carbon ecosystems. Plant invasion led to important trade‐offs in the soil microbiome by promoting bacterial richness, while resulting in biotic homogenization of bacterial communities. Plant invasion was further associated with an important reduction in the complexity and stability of microbial networks, and resulted in an important decoupling between soil microbes and carbon pools.
Background and aims
Kandelia obovata
, a dominant mangrove species in China, produces complex buttress roots and prop roots in intertidal wetlands where high quantities of nitric oxide (NO) are ...produced by reducing sediments. NO, a key signaling molecule, participates in an array of plant physiological and developmental processes. However, it is unclear whether NO functions in
K. obovata
root system establishment.
Methods
Here, we used a transcriptomic approach to investigate the potential role of NO in the regulation of
K. obovata
lateral root development and growth. Transcript profiles and bioinformatics analyses were used to characterize potential regulatory mechanisms.
Results
Application of exogenous sodium nitroprusside (SNP, an NO donor) enhanced
K. obovata
lateral root development and growth in a dose-dependent manner. Furthermore, the effects of SNP were abolished by the addition of cPTIO (NO scavenger). RNA-seq analysis identified 1,593 differentially expressed genes (DEGs), of which 646 and 947 were up- and down-regulated in roots treated with NO donor. Functional annotation analysis demonstrated that the starch and sucrose pathway was significantly induced in response to NO. A suite of DEGs involved in hormone signal transduction and cell wall metabolism was also differentially regulated by NO. Taken together, our results suggest that a complex interaction between energy metabolism, multiple hormone signaling pathways, and cell wall biosynthesis is required for the NO regulation on lateral root development and growth in mangrove plant
K. obovata
.
Conclusion
NO appears to contribute to the formation of the unique root system of mangrove plants.
Background and aims
Avicennia marina
is a pioneer mangrove species widely distributed along the southeast coast of China. It suffers, especially in the seedling stage, from the tidal flooding and ...anaerobic surroundings as it closes to the seaward side. The aim of this study is to assess the ability of
A. marina
seedlings to withstand different tidal inundations by physiological and proteomic approaches.
Methods
To accomplish this, the artificial tidal inundations were mimicked as 0, 4, and 8 h per tidal cycle about 1 week. The physiological approaches and two-dimensional electrophoresis coupled with MALDI-TOF/TOF-MS technology were used to reveal the adaptive alterations of
A. marina
seedlings to tidal inundation.
Results
There were profound changes in photosynthesis and chlorophyll fluorescence characteristics of
A. marina
seedling leaves under inundation treatment. Particularly, photosynthetic rate increased at 4 h inundation, while decreasing at 8 h inundation treatment compared with control (0 h). The results highlighted that
A. marina
seedlings could greatly upregulate the abundances of photosynthesis-related proteins, activate antioxidant and defense systems to efficiently suppress the reactive oxygen species (ROS) burst and cell damages, mobilize carbohydrate metabolism associated proteins, and then maintain cellular homeostasis, resulting in well adaptation to short-term tidal inundation.
Conclusion
Overall, our results demonstrated that short-term inundation is beneficial, while long-term inundation is detrimental to
A. marina
. The results allow us to recognize the roles of specific proteins in molecular tolerance to tidal inundation in mangrove plants.
Gao, G.-F.; Zhang, X.-M.; Li, P.-F.; Simon, M.; Shen, Z.-J.; Chen, J.; Gao, C.-H., and Zheng, H.L., 2020. Examining soil carbon gas (CO2, CH4) emissions and the effect on functional microbial ...abundances in the Zhangjiang Estuary Mangrove Reserve. Journal of Coastal Research, 36(1), 54–62. Coconut Creek (Florida), ISSN 0749-0208. Mangrove soil is regarded as an important source of CO2 and CH4 because of its large carbon pools. However, little is known about the magnitudes of CO2 and CH4 emitted from mangrove soils and their relationships with functional microbial abundances. Here, a field experiment was conducted in Zhangjiang Estuary Mangrove from August 2014 to September 2016. Soils dominated by species Kandelia obovata (KO), Avicennia marina (AM), and bare mudflat (Mud) were randomly established, respectively. The results showed that soil of the Zhangjiang Estuary Mangrove wetland is a significant source of CH4 (ranging from –35.36 to 2822.52 µg m–2 h–1) and CO2 (ranging from –28.45 to 116.26 mg m–2 h–1), with a significant spatial and seasonal variation pattern. The soil CH4 emissions were positively correlated to the mcrA gene abundance and organic matter content. Meanwhile, the 16S rRNA and ANME-pmoA gene abundances were positively correlated to the soil CO2 emissions. When considering only the soil-atmosphere exchange of carbon gas, soil CO2 emission was the major contributor to the global warming potential, accounting for 64.66%–96.11%. The profound variations of soil CH4 and CO2 emissions may imply the important role of dominant mangrove vegetation on soil microbes and carbon gas emissions.
The role of dyslipidemia in pancreatic neuroendocrine tumors (PanNENs) is unclear. The aim of this study is to analyze the characteristics of serum lipid spectrum in PanNENs, and the effect of the ...variation in lipid profile on the development of PanNENs clinicopathological features and prognosis.
All PanNENs patients between November 2012 and September 2020 in the authors' research center were identified from patient medical records and databases. A total of 185 with PanNENs patients were ultimately included in this study, including 100 nonfunctional PanNENs and 85 insulinomas. Clinicopathologic features, serum lipid level and overall survival results were retrospectively analyzed using statistical methods.
In 185 PanNENs, 95 (51.4%) patients appear to have dyslipidemia. Patients with insulinoma had a lower proportion of abnormal HDL than those with nonfunctional PanNENs (10.6% vs 23%, P=0.026). The mean serum HDL levels of insulinomas were 0.131 mmol/L higher than the NF-PanNENs (1.306 ± 0.324 vs 1.175 ± 0.315, P=0.006). In multivariate logistic analysis, high levels of HDL are negatively correlated to tumor size (OR 0.233, 95% CI: 0.069-0.790, P=0.019), but HDL was not associated with pathological grade or metastasis. And a correlation has been found between hypercholesterolemia and the original location of the tumor (OR:0.224, 95%CI: 0.066-0.753, P =0.016). In addition, the outcome of the survival analysis revealed that dyslipidemia did not influence the prognosis of PanNENs patients (P>0.05).
HDL was negatively correlated with the tumor size of PanNENs. The serum HDL level of insulinoma patients is higher than nonfunctional PanNENs.
Chinese mangrove, an important ecosystem in coastal wetlands, is sensitive to the invasive alien species Spartina alterniflora. However, the effects of the S. alterniflora invasion on mangrove soil N
...O emissions and the underlying mechanisms by which emissions are affected have not been well studied. In this study, the N
O emitted from soils dominated by two typical native mangroves (i.e. Kandelia obovata: KO; Avicennia marina: AM), one invaded by S. alterniflora (SA), and one bare mudflat (Mud) were monitored at Zhangjiang Mangrove Estuary (where S. alterniflora is exotic). Together with soil biogeochemical properties, the potential denitrification rate and the composition of soil bacterial communities were determined simultaneously by
NO
tracer and high-throughput sequencing techniques, respectively. Our results showed that S. alterniflora invasion significantly (p < 0.05) increases soil N
O emissions by 15-28-fold. In addition, isotope results revealed that the soil potential denitrification rate was significantly (p < 0.05) enhanced after S. alterniflora invasion. Moreover, the S. alterniflora invasion significantly (p < 0.05) decreased soil bacterial α-diversity and strongly modified soil bacterial communities. Indicator groups strongly associated with S. alterniflora were Chloroflexia, Alphaproteobacteria, and Bacilli, each of which was abundant and acts as connector in the co-occurrence network. FAPROTAX analysis implied that the S. alterniflora invasion stimulated soil denitrification and nitrification while depressing anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA). Redundancy analysis (RDA) found that soil organic matter (SOM) and pH were the most important environmental factors in altering soil bacterial communities. Taken together, our results imply that the S. alterniflora invasion in mangrove wetlands significantly stimulates soil denitrification and N
O emissions, thereby contributing N
O to the atmosphere and contributing to global climate change.
Mangroves are the main intertidal ecosystems with varieties of root types along the tropical and subtropical coastlines around the world. The typical characteristics of mangrove habitats, including ...the abundant organic matter and nutrients, as well as the strong reductive environment, are favor for the production of hydrogen sulfide (H2S). H2S, as a pivotal signaling molecule, has been evidenced in a wide variety of plant physiological and developmental processes. However, whether H2S functions in the mangrove root system establishment is not clear yet. Here, we reported the possible role of H2S in regulation of Kandelia obovata root development and growth by TMT-based quantitative proteomic approaches coupled with bioinformatic methods. The results showed that H2S could induce the root morphogenesis of K. obovata in a dose-dependent manner. The proteomic results successfully identified 8,075 proteins, and 697 were determined as differentially expressed proteins. Based on the functional enrichment analysis, we demonstrated that H2S could promote the lateral root development and growth by predominantly regulating the proteins associated with carbohydrate metabolism, sulfur metabolism, glutathione metabolism and other antioxidant associated proteins. In addition, transcriptional regulation and brassinosteroid signal transduction associated proteins also act as important roles in lateral root development. The protein-protein interaction analysis further unravels a complicated regulation network of carbohydrate metabolism, cellular redox homeostasis, protein metabolism, secondary metabolism, and amino acid metabolism in H2S-promoted root development and growth of K. obovata. Overall, our results revealed that H2S could contribute to the morphogenesis of the unique root system of mangrove plant K. obovata, and play a positive role in the adaption of mangrove plants to intertidal habitats.
Cadmium (Cd) is a harmful heavy metal that affects the growth and development of plants. Nitrogen (N) is an essential nutrient for plants, and appropriate N management can improve Cd tolerance. The ...aim of our study was to explore the effects of different forms of N on the molecular and physiological responses of the hyperaccumulator Solanum nigrum to Cd toxicity. Measurement of biomass, photosynthetic parameters, and Cd2+ fluxes using non-invasive micro-test technique, Cd fluorescent dying, biochemical methods and quantitative real-time PCR analysis were performed in our study. Our results showed that ammonium (NH4+) has stronger Cd detoxification ability than nitrate (NO3-), which are likely attributed to the following three reasons: (1) NH4+ decreased the influx and accumulation of Cd2+ by regulating the transcription of Cd transport-related genes; (2) the ameliorative effects of NH4+ were accompanied by the increased retention of Cd in the cell walls of roots; and (3) NH4+ up-regulated SnExp expression.
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•NH4+ alleviated growth inhibition of Solanum nigrum caused by Cd better than NO3-.•NH4+ reduced Cd2+ influx in root tips and root protoplasts measured by NMT.•Cd fixation in root cell walls was higher under NH4+ supply compared with NO3- supply.•NH4+ increased the expression of SnEXP and the biosynthesis of pectin and HC1 in roots.•NH4+ enhanced Cd resistance by regulating the transcription of Cd transport-related genes.
Mangrove ecosystems are an important component of “blue carbon”. However, it is not clear whether the stems play roles in the CH4 budget of mangrove ecosystems. This study investigated the CH4 ...emission from mangrove stems and its potential driving factors. We set up six sample plots in the Zhangjiang Estuary National Mangrove Nature Reserve, where Kandelia obovata, Avicennia marina and Aegiceras corniculata are the main mangrove tree species. Soil properties such as total carbon content, redox potential and salinity were determined in each plot. The dynamic chamber method was used to measure mangrove stems and soil CH4 fluxes. Combined field survey results with Principal Component Analysis (PCA) of soil properties, we divided the six plots into two sites (S1 and S2) to perform statistical analyses of stem CH4 fluxes. Then the CH4 fluxes from mangrove tree stems and soil were further scaled up to the ecosystem level through the mapping model. Under different backgrounds of soil properties, salinity and microbial biomass carbon were the main factors modified soil CH4 fluxes in the two sites, and further affected the stem CH4 fluxes of mangroves. The soil of both sites are sources of CH4, and the soil CH4 emission of S2 was about twice higher than that of S1. Results of upscaling model showed that mangrove stems in S1 were CH4 sinks with −105.65 g d−1. But stems in S2 were CH4 sources around 1448.24 g d−1. Taken together, our results suggested that CH4 emission from mangrove soils closely depends on soils properties. And mangrove stems were found to act as both CH4 sources and CH4 sinks depend on soil CH4 production. Therefore, when calculating the CH4 budget of the mangrove ecosystem, the contribution of mangrove plant stems cannot be ignored.
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•Both CH4 emission and consumption from mangrove stems were found for the first time.•Whether stems act as CH4 source or sink depend on soil CH4 production.•Salinity and microbial biomass carbon were the main factors affected soil CH4 flux.•K. obovata stems were CH4 sinks in site 1 while were CH4 sources in site 2.•Stems in total of 62.3 ha mangroves in the Zhangjiang estuary emitted about 1342.59 g CH4 d−1.
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