Eucalyptus bacterial wilt, caused by the Ralstonia solanacearum species complex (RSSC), is characterized by sudden and destructive outbreaks. Field epidemiological surveys revealed that the disease outbreak exhibits distinct temporal patterns, progressing from low-level accumulation to rapid spread over the years, with the core period of annual outbreak occurring from late August to early October. The pathogen colonized the entire tree at an early stage of disease development. The abundance and spatial distribution of the pathogen in the soil around infected trees exhibit a phased pattern: low and uniform abundance in the early stage, sudden outbreak and patchy expansion at the root collar during the middle stage, and high and uniform abundance in the advanced stage. Time-course branch inoculation experiments further showed that the pathogen first established dense populations near the inoculation site, then spread asymptomatically to distal tissues, followed by synchronized population surges across multiple stem segments during the intermediate and late stages. Microbial Communities profiling revealed that, compared with the stable structural characteristics of the endophytic bacterial community in healthy eucalyptus trees, at the intermediate stage, the xylem endophytic community transitioned from a critically reorganized state characterized by the coexistence of diverse taxa to a collapsed stable state overwhelmingly dominated by Ralstonia. Collectively, these findings indicate that eucalyptus bacterial wilt epidemics progress through distinct phases of early low-level spread, an intermediate breakthrough, and a late-stage outbreak. Pathogen-driven dysbiosis and collapse of the xylem microecosystem may therefore represent a key mechanism underlying rapid disease outbreaks, with collapse of the xylem endophytic microbial communities serving as a sentinel biomarker marking a critical transition in disease progression.
Fusarium crown rot (FCR), predominantly caused by the soil-borne pathogen Fusarium pseudograminearum, poses a severe and escalating threat to global wheat (Triticum aestivum L.) production and food security. This review consolidates recent advances in understanding the pathogen’s biology, infection strategies, host–pathogen interactions, and sustainable management practices. F. pseudograminearum deploys trichothecene mycotoxins, particularly deoxynivalenol (DON), to undermine host immunity, with its virulence governed by transcription factors and functional proteins involved in fungal growth, toxin biosynthesis, and stress adaptation. In response, wheat initiates a multilayered defense mechanism, primarily by upregulating genes related to toxin detoxification and transport, hormonal signaling, and structural reinforcement. Integrated disease management (IDM) practices aimed at mitigating disease severity include agronomic interventions, fungicides, biocontrol agents, and breeding efforts supported by quantitative trait locus (QTL) mapping, genome-wide association (GWAS) studies, and genome editing. To address the dynamic nature of F. pseudograminearum populations under changing environmental conditions, future directions should prioritize climate-resilient strategies, integrated multi-omics approaches, drone-based early detection technologies, and global pathogen surveillance systems. This review provides an updated framework to guide sustainable and effective FCR control.
Soil microbial carbon use efficiency (CUE) plays a critical role in carbon (C) cycling and ecosystem functioning, yet its response to nitrogen (N) deposition remains poorly understood, particularly in planted forests. This study investigates how N addition affects microbial CUE and its underlying mechanisms in Populus deltoides plantations in coastal eastern China. Using a long-term field experiment with five levels of N addition (0–30 g N·m−2·yr−1), we measured microbial CUE, soil chemical properties, enzyme activities, and microbial community composition from 2018 to 2020. We found that N addition significantly reduced microbial CUE, primarily through N-induced stoichiometric imbalances and soil acidification. Excess N increased available N and decreased the DOC:AN ratio, driving microbial carbon limitation and reducing metabolic efficiency. Furthermore, N addition suppressed bacterial diversity and shifted microbial communities toward taxa with lower CUE. Model selection identified soil pH, available N, and DOC:AN as key predictors of microbial CUE. These findings highlight the dominant role of soil environmental factors—particularly nutrient stoichiometry and pH—in regulating microbial CUE. Our results suggest that excessive N deposition may compromise soil C sequestration in poplar plantations by altering microbial resource allocation and reducing microbial metabolic efficiency. Managing nutrient balance and maintaining microbial diversity are thus critical for sustaining soil health and carbon storage in forest ecosystems under increasing N deposition.
Hydrogels, despite their potential in flexible electronics and wearable sensors, often suffer from inadequate mechanical robustness under sustained loading. This study aims to overcome this limitation by developing a novel nanocomposite hydrogel system through the integration of calcium-polyoxometalate sub-nanometer wires (Ca-POM SNWs) into a polyvinyl alcohol (PVA) matrix. Utilizing a H2O/ethylene glycol (EG) binary solvent, the hydrogel achieves uniform dispersion of Ca-POM SNWs, which enhances mechanical properties through dual reinforcement mechanisms: stress dissipation via polymer-mimetic flexibility and crystallinity improvement via hydrophobic ligand-induced chain alignment. The resulting PVA/Ca-POM hydrogel exhibits exceptional performance, including a 2.4-fold increase in fracture stress (0.85 MPa), 3.8-fold toughness enhancement (2.76 MJ m−3), and high ionic conductivity (3.6 S m−1). As a strain sensor, it achieves a gauge factor of 2.56 with rapid response, enabling precise detection of both large joint movements and subtle physiological vibrations. A prototype Morse code communication system further demonstrates its potential in assistive healthcare technologies, facilitating barrier-free, real-time communication between disabled patients and clinicians. This work highlights a breakthrough in inorganic-organic interface compatibility, offering a versatile platform for next-generation wearable technologies and extreme-environment applications. The innovative design principles and multifunctional performance underscore its significance in advancing soft material engineering.
TaDJA-6D boosts wheat regeneration and transformation efficiency across genotypes, offering a new molecular breeding resource. As a key member of the heat shock protein 40 family, the co-chaperone DnaJ proteins play a crucial role in plant growth, development, and stress responses. However, very few studies have focused on the function of DnaJ protein in wheat (Triticum aestivum L.). Here, we characterized a DnaJ family gene from wheat, TaDJA-6D, (TraesCS6D02G232600) and analyzed its spatiotemporal expression pattern. During wheat regeneration, the transcriptional expression level of the TaDJA-6D gene was continuously upregulated with the extension of tissue culture time; in situ hybridization revealed that the genes were highly expressed in the vigorously dividing regions of wheat calli. Functional analysis demonstrated that, compared with the control vector, overexpression of TaDJA-6D significantly improved the wheat regeneration and transformation efficiency across diverse wheat genotypes, including Fielder, Kenong 199, Yanda 1817 and Xiaoyan 6. Our findings suggest that TaDJA-6D plays an important role in the process of wheat regeneration and genetic transformation. This study deepens our understanding of the functions of wheat co-chaperone proteins and provides novel genetic resources for efficient wheat transformation.
