Nitrogen (N) deposition has increased in recent years and is significantly affected by global change and human activities. Wetlands are atmospheric CH₄ and N₂O sources and may be affected by changes in N deposition. To reveal the effects of increased N deposition on peatland greenhouse gas exchange, we observed the CH₄ and N₂O emissions from controlled microcosms collected from a temperate peatland in the Xiaoxing’an mountains, Northeast China. We found that the moss biomass did not change, but the total herb biomass increased by 94% and 181% with 5 and 10-times-higher N deposition, respectively. However, there were no significant changes in CH₄ emissions from the microcosms with N addition. The unchanged CH₄ emissions were mainly caused by the opposite effect of increased nitrate and ammonium concentrations on soil CH₄ production and the increased plant biomass on CH₄ emission. We also found that the manipulated microcosms with 5 and 10-times-higher N deposition had 8 and 20-times-higher seasonal average N₂O emissions than the control microcosms, respectively. The increased N₂O emissions were mainly caused by short-term (≤7 d) pulse emissions after N addition. The pulse N₂O emission peaks were up to 1879.7 and 3836.5 μg m⁻² h⁻¹ from the microcosms with 5 and 10-times-higher N deposition, respectively. Nitrate and ammonium concentrations increasing in the soil pore water were the reason for the N₂O emissions enhanced by N addition. Our results indicate that the increase in N deposition had no effects on the CH₄ emissions but increased the N₂O emissions of the temperate peatland. Moreover, pulse emissions are very important for evaluating the effect of N addition on N₂O emissions.

Forever Summer Hydrangea (Hydrangea macrophylla) is a common flowering plant in the Yangtze River Valley area of China, and it is widely cultivated globally (Chen et al. 2015). In July 2023, H. macrophylla leaves exhibiting visible diseased lesions were reported in a nursery in Wuhu, Anhui Province, China. The incidence reached 40% in a 0.2 ha area. The primary disease symptom was multiple irregular necrotic spots (0.5 to 1 mm in diameter) appearing on the leaves. These spots on the leaves were faded yellow around the perimeter and grayish brown in the center.). 15 leaf samples were sterilized with 75% alcohol and rinsed three times in sterile distilled water, then transferred to antibiotic-added potato dextrose agar (PDA) for incubation at 27°C. The colonies were fluffy, flocculent, or hairy, dark green, gray-green to gray-brown in color, and spreading or protruding punctate with a colorless halo on PDA. The conidiophores were brown to dark brown, smooth or rough surface, mostly unbranched, clearly differentiated, erect or curved. The conidia displayed a light brown to brown hue, lemon shape, fusiform, elongated ellipsoid or others with obvious spore markings and spore umbilicus. Genomic DNA was extracted from fungal colonies on infected leaves of three collections separately (Braun et al. 2003) and the internal transcribed spacer regions (ITS), actin (ACT) genes and partial translation elongation factor-l-alpha (EF) were amplified and sequenced using the primers ITS1/4 (Yin et al. 2012), ACT-512F/ACT-783R and EF 1-728F/986R (Carbone and Kohn 1999), respectively. DNA sequences of isolates were identical and deposited in GenBank (accession no. OR362754 for ITS, OR611929 for ACT and PP209106 for EF). The consensus sequences from ITS, EF and ACT showed 100%, 98.98% and 100% identical to Cladosporium strains (accession no. OQ186140.1, MT154169.1 and OL322092.1), respectively. To confirm the pathogenicity of the isolates, hydrangeas were planted in 15-cm pots containing commercial potting mix (one plant/pot). Three healthy plants were inoculated at the five to eight leaf stage by spraying 50 μL of the isolate conidial suspension (4 × 106 spores/mL) on healthy leaves. Three plants treated with sterile distilled water were used as controls. After inoculation, all plants were placed in a humidity chamber (>95% relative humidity, 26°C) for 48 h and then transferred to a greenhouse at 22/27°C. All inoculated leaves exhibited symptoms similar to those observed in the nursery 10 days after inoculation, while no symptoms were observed for control leaves. The fungus was re-isolated and confirmed to be C. tenuissimum. Based on the above morphological characterization and molecular identification, the causal agent for this leaf spot disease was identified as C. tenuissimum. Although C. tenuissimum has been reported to cause disease on H. paniculata in northern China (Li et al.2021), this is the first time that C. tenuissimum has been found on H. macrophylla in southern China. This new disease of H. macrophylla caused by C. tenuissimum is a threat to urban greening and is worth further investigation.

Poria cocos (syn. Wolfiporia cocos) is an obligate saprophytic fungus that can produce sclerotia only when cultivated on pine wood. Despite its wide cultivation, the nutritional adaptation of this fungus to pine substrate and the host defensive responses triggered during colonization remain poorly characterized. Elucidating how Poria cocos colonizes pine and triggers host defenses is critical to uncover its nutrient dependence. GO and KEGG analyses revealed that protein degradation, carbon metabolism, protein processing in the endoplasmic reticulum, and proteasome pathways were the major enriched pathways, indicating that a large amount of pine wood protein was degraded after Poria cocos colonization. Consistent with these omics signatures, the fungus acquired its primary nitrogen source via breakdown of pine structural and metabolic proteins, while pine carbohydrates acted as its main carbon source. Nutritional profiling confirmed the depletion of soluble protein and total sugars in pine wood, alongside elevated defensive polyphenols and flavonoids, reflecting an active stress response from viable pine parenchyma cells upon colonization. No significant shifts in mineral element concentrations were detected in colonized pine wood, indicating that Poria cocos selectively absorbs target minerals without altering the overall mineral pool of host wood tissue. Collectively, this work elucidates the core nutritional strategy of Poria cocos during pine colonization and identifies key molecular clues to advance optimized artificial cultivation, laying a solid theoretical foundation for revealing its obligate saprophytic lifestyle.