Soil organic carbon (SOC) contributes the most significant portion of carbon storage in the terrestrial ecosystem. The potential for variability in carbon losses from soil can lead to severe ...consequences such as climate change. While extensive studies have been conducted to characterize how land cover type, soil texture, and topography impact the distribution of SOC stocks across different ecosystems, little is known about in Karst Region. Here, we characterized SOC stocks with intensive sampling at the local scale (495 representative samples) via Random Forest Regression (RF) and Principal Component Analysis (PCA). Our findings revealed significant differences in SOC stock among land cover types, with croplands exhibiting the lowest SOC stocks, indicating that management practices could play a crucial role in SOC stocks. Conversely, there was little correlation between SOC stock and clay percentage, suggesting that soil texture was not a primary factor influencing SOC at a local scale. Further, Annual Precipitation was identified as the key driving factor for the dynamics of SOC stocks with the help of RF and PCA. A substantial SOC deficit was observed in most soils in this study, as evaluated by a SOC/clay ratio, indicating a significant potential in SOC sequestration with practical measures in the karst region. As such, future research focused on simulating SOC dynamics in the context of climate change should consider the controlling factors at a local scale and summarize them carefully during the up-scaling process.
When plants are subjected to cold stress, they undergo a series of molecular and physiological changes to protect themselves from injury. Indica cultivars can usually withstand only mild cold stress ...in a relatively short period. Hormone-mediated defence response plays an important role in cold stress. Weighted gene co-expression network analysis (WGCNA) is a very useful tool for studying the correlation between genes, identifying modules with high phenotype correlation, and identifying Hub genes in different modules. Many studies have elucidated the molecular mechanisms of cold tolerance in different plants, but little information about the recovery process after cold stress is available.
To understand the molecular mechanism of cold tolerance in rice, we performed comprehensive transcriptome analyses during cold treatment and recovery stage in two cultivars of near-isogenic lines (9311 and DC907). Twelve transcriptomes in two rice cultivars were determined. A total of 2509 new genes were predicted by fragment splicing and assembly, and 7506 differentially expressed genes were identified by pairwise comparison. A total of 26 modules were obtained by expression-network analysis, 12 of which were highly correlated with cold stress or recovery treatment. We further identified candidate Hub genes associated with specific modules and analysed their regulatory relationships based on coexpression data. Results showed that various plant-hormone regulatory genes acted together to protect plants from physiological damage under short-term low-temperature stress. We speculated that this may be common in rice. Under long-term cold stress, rice improved the tolerance to low-temperature stress by promoting autophagy, sugar synthesis, and metabolism.
Through WGCNA analysis at the transcriptome level, we provided a potential regulatory mechanism for the cold stress and recovery of rice cultivars and identified candidate central genes. Our findings provided an important reference for the future cultivation of rice strains with good tolerance.
Sporisorium scitamineum is the causative agent responsible for smut disease of sugarcane worldwide. However, lack of efficient gene manipulation system makes this fungus much behind the type model of ...the smut fungi in molecular biology. Here, we report the development of a CRISPR/Cas9 and T-DNA based dual vector system that allowed efficient knock-out or knock-in of a gene of interest in the S. scitamineum in a site-specific manner. By using Mfa2, a key player in the mating event in S. scitamineum as a tester gene, site-specific insertions of the introduced fragments were achieved both for Mfa2 knockout and complementation. Of particular advantage of this system is the simplicity of selection and identification for the desired transformants by using drug resistance coupled with PCR. This system greatly facilitates the gene function study in S. scitamineum, and could potentially be used for other basidiomycete fungi.
Low temperature at the seedling stage is a major damaging factor for rice production in southern China. To better understand the cold response of cultivated and wild rice, cold-sensitive cultivar ...93-11 (Oryza sativa L. ssp. Indica) and cold-resistant hybrid wild rice DC907 with a 93-11 genetic background were used for a quantitative proteomic analysis with tandem mass tags (TMT) in parallel. Rice seedlings grown for four weeks at a normal temperature (25°C) were treated at 8-10°C for 24, 72 and 120 h. The number of differentially expressed proteins increased gradually over time in the cold-exposed rice in comparison with the untreated rice. A total of 366 unique proteins involved in ATP synthesis, photosystem, reactive oxygen species, stress response, cell growth and integrity were identified as responding to cold stress in DC907. While both DC907 and 93-11 underwent similar alterations in proteomic profiles in response to cold stress, DC907 responded in a prompter manner in terms of expressing cold-responding proteins, maintained a higher level of photosynthesis to power the cells, and possessed a stable and higher level of DIR proteins to prevent the plant from obtaining irreversible cell structure damage. The observations made in this study may lay a new foundation for further investigation of cold sensitivity or tolerance mechanisms in rice.
Syntheses of carbonate chemistry spatial patterns are important for predicting ocean acidification impacts, but are lacking in coastal oceans. Here, we show that along the North American Atlantic and ...Gulf coasts the meridional distributions of dissolved inorganic carbon (DIC) and carbonate mineral saturation state (Ω) are controlled by partial equilibrium with the atmosphere resulting in relatively low DIC and high Ω in warm southern waters and the opposite in cold northern waters. However, pH and the partial pressure of CO
(pCO
) do not exhibit a simple spatial pattern and are controlled by local physical and net biological processes which impede equilibrium with the atmosphere. Along the Pacific coast, upwelling brings subsurface waters with low Ω and pH to the surface where net biological production works to raise their values. Different temperature sensitivities of carbonate properties and different timescales of influencing processes lead to contrasting property distributions within and among margins.
The combined effects of anthropogenic and biological CO
inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would ...contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H
S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H
S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO
uptake, and CO
and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.The potential contribution of redox reactions to acidification in coastal waters is unclear. Here, using measurements from the Chesapeake Bay, the authors show that pH minimum occurs at mid-depths where acids are produced via hydrogen sulfide oxidation in waters mixed upward from anoxic depths.
SUMOylation is an important post-translational modification that regulates the expression, localization, and activity of substrate proteins, thereby participating in various important cellular ...processes such as the cell cycle, cell metabolism, gene transcription, and antiviral activity. However, the function of SUMOylation in phytopathogenic fungi has not yet been adequately explored.
A comprehensive analysis composed of proteomics, affinity pull-down, molecular and cellular approaches was performed to explore the roles of SUMOylation in
, the fungal pathogen responsible for chestnut blight.
, the gene encoding the SUMO protein CpSmt3 in
was identified and characterized. Deletion of the
gene resulted in defects in mycelial growth and hyphal morphology, suppression of sporulation, attenuation of virulence, weakening of stress tolerance, and elevated accumulation of hypovirus dsRNA. The Δ
deletion mutant exhibited an increase in mitochondrial ROS, swollen mitochondria, excess autophagy, and thickened cell walls. About 500 putative SUMO substrate proteins were identified by affinity pull-down, among which many were implicated in the cell cycle, ribosome, translation, and virulence. Proteomics and SUMO substrate analyses further revealed that deletion of
reduced the accumulation of CpRho1, an important protein that is involved in TOR signal transduction. Silencing of
resulted in a phenotype similar to that of Δ
, while overexpression of CpRho1 could partly rescue some of the prominent defects in Δ
. Together, these findings demonstrate that SUMOylation by CpSmt3 is vitally important and provide new insights into the SUMOylation-related regulatory mechanisms in
.
Dirigent proteins (DIRs) are known to function in lignin biogenesis and to be involved in stress resistance in plants. However, the sugarcane DIRs have not been functionally characterized. In this ...study, we investigated the DIR-protein-encoding genes in
spp. (ScDIR) by screening collections of sugarcane databases, monitoring the responses of these genes to drought stress by real-time quantitative PCR, and identifying their heterologous expression in tobacco. Of the 64
identified, four belonging to the DIR-b/d (
and
) and DIR-c (
and
) subfamilies showed a significant transcriptional response when subjected to drought stress. ScDIR5, ScDIR7, and ScDIR11 are localized in the cell membrane, whereas ScDIR40 is found in the cell wall. The overexpression of these
genes in tobacco generally increased the drought tolerance of the transgenic lines, with ScDIR7 conferring the highest degree of drought tolerance. The characterization of the physiological and biochemical indicators (superoxide dismutase, catalase, malondialdehyde, and H
O
) confirmed that the ScDIR-overexpressing lines outperformed the wild type. These results demonstrated that specific
in sugarcane respond and contribute to tolerance of drought stress, shedding light on potential means of improving drought tolerance in this crop.
In a survey of mycoviruses in
species that cause sugarcane Pokkah boeng disease, twelve
strains from three
species (
,
, and
) were found to contain Fusarium sacchari hypovirus 1 (FsHV1), which we ...reported previously. The genomes of these variants range from 13,966 to 13,983 nucleotides, with 98.6% to 99.9% nucleotide sequence identity and 98.70% to 99.9% protein sequence similarity. Phylogenetic analysis placed these FsHV1 variants within the
cluster of
. Intriguingly, no clear correlation was found between the geographic origin and host specificity of these viral variants. Additionally, six out of the twelve variants displayed segmental deletions of 1.5 to 1.8 kilobases, suggesting the existence of defective viral dsRNA. The presence of defective viral dsRNA led to a two-thirds reduction in the dsRNA of the wild-type viral genome, yet a tenfold increase in the total viral dsRNA content. To standardize virulence across natural strains, all FsHV1 strains were transferred into a single, virus-free
recipient strain, FZ06-VF, via mycelial fusion. Strains of
carrying FsHV1 exhibited suppressed pigment synthesis, diminished microspore production, and a marked decrease in virulence. Inoculation tests revealed varying capacities among different FsHV1 variants to modulate fungal virulence, with the strain harboring the FsHV1-FSA1 showing the lowest virulence, with a disease severity index (DSI) of 3.33, and the FsHV1-FS1 the highest (DSI = 17.66). The identification of highly virulent FsHV1 variants holds promise for the development of biocontrol agents for Pokkah boeng management.
Sugarcane smut, caused by the fungal pathogen
, is a prominent threat to the sugarcane industry. The development of smut resistant varieties is the ultimate solution for controlling this disease, due ...to the lack of other efficient control methods. Artificial inoculation method is used to evaluate the virulence differentiation of pathogens. The mostly used artificial inoculation methods are soaking of the seed canes in the teliospore solution and injection of teliospores or haploid sporidia into the sugarcane sprouts. However, due to the infection nature of the pathogen that invades the sugarcane plant through meristem tissue of the sprout or shoot, the rate of successful infection is often low and fluctuated, resulting in low confidence of the assays. We recently reported a rapid and high-throughput inoculation method called plantlet soaking by using tissue culture-derived sugarcane plantlets as the test plants. Here, we compare different inoculation methods and report the characterization of parameters that may affect the sensitivity and efficiency of the plantlet soaking technique. The results showed that sugarcane plantlets were highly vulnerable to infection, even with the inoculum density at 6.0 × 10
basidial spores/ml, and this method could be applied to all varieties tested. Notably, varieties showing high smut resistance in the field exhibited high susceptibility when inoculated with the plantlet soaking method, suggesting that the plantlet soaking method is a good complement to the traditional methods for screening germplasms with internal resistance. In addition, this method could also be used to monitor the variation of cellular virulence of the smut pathogen strains in the field.
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