A Gram-positive, aerobic, rod-shaped mesophilic bacterium was isolated from birch wood, referred to as the AB strain. Allergological tests suggest that this strain may cause allergic alveolitis in sawmill workers. Employing a polyphasic taxonomic approach, the AB strain\'s 16S rRNA gene sequence showed high similarity to Microbacterium barkeri and M. oryzae, with 97.25% and 96.91%, respectively, a finding supported by rpoB and gyrB sequence analysis. Further genome sequence comparison with the closely related M. barkeri type strain indicated a digital DNA-DNA hybridization value of 25.5% and an average nucleotide identity of 82.52%. The AB strain\'s cell wall peptidoglycan contains ornithine, and its polar lipids comprise diphosphatidylglycerol, phosphatidylglycerol, and unidentified glycolipids. Its major fatty acids include anteiso C15:0, anteiso C17:0, and iso C16:0, while MK-10 is its predominant respiratory quinone. Comprehensive analysis through 16S rRNA, whole-genome sequencing, phenotyping, chemotaxonomy, and MALDI-TOF MS profiling indicates that the AB strain represents a new species within the Microbacterium genus. It has been proposed to name this species Microbacterium betulae sp. nov., with ABT (PCM 3040T = CEST 30706T) designated as the type strain.

The biogeochemical cycles of trace elements are changed by fire as a result of the mineralization of organic matter. Monitoring the accumulation of trace elements in both the environment and the tree biomass during the post-fire (PF) forest ecosystem regeneration process is important for tree species selection for reforestation in ecosystems under anthropogenic pressure. We analyzed the soil concentrations of different groups of potentially toxic elements (PTEs), including beneficial (Al), toxic (Cd, Cr, Pb), and microelements (Cu, Mn, Ni, Zn), and their bioaccumulation in the tree species (Pinus sylvestris, Betula pendula, Alnus glutinosa) biomass introduced after a fire in a forest weakened by long-term emissions of industrial pollutants. The results indicated no direct threat from the PTEs tested at the PF site. The tree species introduced 30 years ago may have modified the biogeochemical cycles of the PTEs through different strategies of bioaccumulation in the belowground and aboveground biomass. Alder had relatively high Al concentrations in the roots and a low translocation factor (TF). Pine and birch had lower Al concentrations in the roots and higher TFs. Foliage concentrations and the TF of Cd increased from alder to pine to birch. However, the highest concentration and bioaccumulation factor of Cd was found in the alder roots. The concentrations of Cr in the foliage and the Cr TFs in the studied species increased from pine to birch to alder. Higher concentrations of Cu and Ni were found in the foliage of birch and alder than of pine. Among the species, birch also had the highest Pb and Zn concentrations in the roots and foliage. We found that different tree species had different patterns of PTE phytostabilization and ways they incorporated these elements into the biological cycle, and these patterns were not dependent on fire disturbance. This suggests that similar patterns might also occur in more polluted soils. Therefore, species-dependent bioaccumulation patterns could also be used to design phytostabilization and remediation treatments for polluted sites under industrial pressure.

Polyploidy is thought to enable species diversification and adaptation to extreme environments. Resolving the ecological differences between a taxon\'s ploidy levels would therefore provide important insights into local adaptation and speciation. The genus Betula includes many polyploids, but estimates of their phylogenetic relationships and evolutionary history are uncertain because of cryptic lineages and species. As one of the southern boundary populations of Betula ermanii in Japan has been shown to have distinctive genetic characteristics and traits, the differences in ploidy levels between three southern boundary and various other Japanese B. ermanii populations were investigated using flow cytometry. Leaf and seed morphologies were also compared. Apart from individuals in southern boundary populations, all those sampled were tetraploid. Individuals from the southern boundary populations were mostly diploid, apart from a few from lower altitude Shikoku populations, which were tetraploid. Leaf and seed morphologies differed between tetraploids and diploids. Diploid individuals were characterized by leaves with a heart-shaped base and many leaf teeth, and seeds with relatively longer wings. The diploid populations could be considered a cryptic relict lineage of B. ermanii, and there is a possibility that this lineage is a diploid ancestor of B. ermanii and a relict population of the Sohayaki element. Further investigation of the Japanese Betula phylogenetic relationships would enable an informed discussion of taxonomic revisions.

Pollen, in addition to allergens, comprise low molecular weight components (LMC) smaller than 3 kDa. Emerging evidence indicates the relevance of LMC in allergic immune responses. However, the interaction of birch pollen (BP)-derived LMC and epithelial cells has not been extensively studied. We investigated epithelial barrier modifications induced by exposure to BP LMC, using the human bronchial epithelial cell line 16HBE14o-. Epithelial cell monolayers were apically exposed to the major BP allergen Bet v 1, aqueous BP extract or BP-derived LMC. Barrier integrity after the treatments was monitored by measuring transepithelial electrical resistance at regular intervals and by using the xCELLigence Real-Time Cell Analysis system. The polarized release of cytokines 24 h following treatment was measured using a multiplex immunoassay. Epithelial barrier integrity was significantly enhanced upon exposure to BP LMC. Moreover, BP LMC induced the repair of papain-mediated epithelial barrier damage. The apical release of CCL5 and TNF-α was significantly reduced after exposure to BP LMC, while the basolateral release of IL-6 significantly increased. In conclusion, the results of our study demonstrate that BP-derived LMC modify the physical and immunological properties of bronchial epithelial cells and thus regulate airway epithelial barrier responses.

White birch (Betula platyphylla Suk.) is an important pioneer tree which plays a critical role in maintaining ecosystem stability and forest regeneration. The growth of birch is dramatically inhibited by salt stress, especially the root inhibition. Salt Overly Sensitive 1 (SOS1) is the only extensively characterized Na+ efflux transporter in multiple plant species. The salt-hypersensitive mutant, sos1, display significant inhibition of root growth by NaCl. However, the role of SOS1 in birch responses to salt stress remains unclear. Here, we characterized a putative Na+/H+ antiporter BpSOS1 in birch and generated the loss-of-function mutants of the birch BpSOS1 by CRISPR/Cas9 approach. The bpsos1 mutant exhibit exceptional increased salt sensitivity which links to excessive Na+ accumulation in root, stem and old leaves. We observed a dramatic reduction of K+ contents in leaves of the bpsos1 mutant plants under salt stress. Furthermore, the Na+/K+ ratio of roots and leaves is significant higher in the bpsos1 mutants than the wild-type plants under salt stress. The ability of Na+ efflux in the root meristem zone is found to be impaired which might result the imbalance of Na+ and K+ in the bpsos1 mutants. Our findings indicate that the Na+/H+ exchanger BpSOS1 plays a critical role in birch salt tolerance by maintaining Na+ homeostasis and provide evidence for molecular breeding to improve salt tolerance in birch and other trees.

Pollution is an integral part of global environmental change, yet the combined and interactive effects of pollution and climate on terrestrial ecosystems remain inadequately understood. This study aims to explore whether pollution alters the impacts of ambient air temperature on the population dynamics of herbivorous insects. Between 1995 and 2005, we studied populations of two closely related moths, Eriocrania semipurpurella and E. sangii, at eight sites located 1 to 64 km from a large copper‑nickel smelter in Monchegorsk, Russia. We found that pollution and temperature influence the performance of Eriocrania larvae mining in the leaves of mountain birch, Betula pubescens var. pumila, through multiple pathways. This is evident from the unconsistent changes observed in larval and frass weight, mine area, and leaf size. We found increases in both leaf quality and larval weight with decreasing pollution levels at both spatial and temporal scales and attributed these to the impact of sulphur dioxide, rather than trace elements (nickel and copper). The quality of birch leaves increased with spring (May) temperatures, enabling Eriocrania larvae to achieve greater weight while consuming less biomass. During the larval growth period (early June to early July), Eriocrania larvae increased their consumption with rising temperatures, presumably to compensate for increased metabolic expenses. Contrary to our expectations, the per capita rate of population change did not correlate with larval weight and did not vary along the pollution gradient. Nevertheless, we detected interactive effects of pollution and climate on the rate of population change. This rate decreased with rising winter temperatures in slightly polluted and unpolluted sites but remained unchanged in heavily polluted sites. We conclude that pollution disrupts mechanisms regulating the natural population dynamics of Eriocrania moths.

The study was carried out in the most industrialised region of southern Poland. Four areas were selected for the study: the vicinity of the Miasteczko Śląskie Zn-Pb-works (ZW; with three transects selected: A, B, and C), and the metalliferous waste heaps (H1, H2, H3). Samples were taken from the surface soil layer, while only mature silver birch (Betula pendula Roth) trees (3-4 m high) growing spontaneously in the study area were selected for the collection of leaves. The analysis of metals including trace metals (TMs; Ag, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Tl, and Zn) in the soil and leaves, as well as the contents of specialized leaf compounds belonging to polyphenols were performed. In general, the B. pendula trees in transects A and B located within 500 m of the furnaces exhibited 3-9 times higher content of TMs in their leaves compared to the plants located further away from the Zn smelter. In contrast, the quantity of TM in trees from transect C was independent of distance. The accumulation of TMs in the leaves was significantly lower in the metalliferous waste heap sites compared to the ZW area. It was hypothesised that the accumulation of TMs in B. pendula leaves would depend on the location and distance from the polluting source. It was demonstrated that TMs content in soil affects the accumulation of phenolic acids and flavonoids.

UNASSIGNED: Allergic sensitization is an essential step in the development of allergic airway inflammation to birch pollen (BP); however, this process remains to be fully elucidated. Recent scientific advances have highlighted the importance of the allergen context. In this regard, microbial patterns (PAMPs) present on BP have attracted increasing interest. As these PAMPs are recognized by specialized pattern recognition receptors (PRRs), this study aims at investigating the roles of intracellular PRRs and the inflammasome regulator NLRP3.
UNASSIGNED: We established a physiologically relevant intranasal and adjuvant-free sensitization procedure to study BP-induced systemic and local lung inflammation.
UNASSIGNED: Strikingly, BP-sensitized Nlrp3-deficient mice showed significantly lower IgE levels, Th2-associated cytokines, cell infiltration into the lung, mucin production and epithelial thickening than their wild-type counterparts, which appears to be independent of inflammasome formation. Intriguingly, bone-marrow chimera revealed that expression of NLRP3 in the hematopoietic system is required to trigger an allergic response.
UNASSIGNED: Overall, this study identifies NLRP3 as an important driver of BP-induced allergic immune responses.

The temperature sensitivities of photosynthesis and respiration remain a key uncertainty in predicting how forests will respond to climate warming. We grew seedlings of four temperate tree species, including Betula platyphylla, Fraxinus mandshurica, Juglans mandshurica and Tilia amurensis, at three temperature regimes (ambient, +2 °C, and +4 °C in daytime air temperature). We investigated net photosynthesis (Anet25), maximum rate of RuBP-carboxylation (Vcmax25) and RuBP-regeneration (Jmax25), stomatal conductance (gs25), mesophyll conductance (gm25), and leaf respiration (Rleaf) in dark (Rdark25) and in light (Rlight25) at 25 °C in all species. Additionally, we examined the temperature sensitivities of Anet, Vcmax, Jmax, Rdark and Rlight in F. mandshurica. Our findings showed that the warming-induced decreases in Anet25, Vcmax25 and Jmax25 were more prevalent in the late-successional species T. amurensis. Warming had negative impacts on gs25 in all species. Overall, Anet25 was positively correlated with Vcmax25 and Jmax25 across all growth temperatures. However, a positive correlation between Anet25 and gs25 was observed only under warming conditions, and gs25 was negatively associated with vapor pressure deficit. This implies that the vapor pressure deficit-induced decrease in gs25 was responsible for the decline in Anet25 at higher temperatures. The optimum temperature of Anet in F. mandshurica increased by 0.59 °C per 1.0 °C rise in growth temperature. While +2 °C elevated the thermal optima of Jmax, it did not affect the other temperature sensitivity parameters of Vcmax and Jmax. Rdark25 was not affected by warming in any species, and Rlight25 was stimulated in T. amurensis. The temperature response curves of Rdark and Rlight in F. mandshurica were not altered by warming, implying a lack of thermal acclimation. The ratios of Rdark25 and Rlight25 to Anet25 and Vcmax25 in T. amurensis increased with warming. These results suggest that Anet and Rleaf did not acclimate to warming synchronously in these temperate tree species.

Quantitative analysis of vessel characteristics at the cellular scale is of great significance for understan-ding plant adaptation strategies to environment. The direct grinding combined with stereo-microscope imaging is one of the main approaches to examine the anatomical structure of xylem (conifer tracheid and hardwood vessel) wood structure, which inevitably damages xylem cells, hindering the accurate understanding of anatomical structures. In this study, we applied X-ray micro-computed tomography (μCT) and stereo-microscope technology to quantitatively measure the diameter and area of vessels of seven Canadian broadleaved tree species (Acer saccharum, Betula papyrifera, Fraxinus americana, Ostrya virginiana, Populus grandidentata, Quercus rubra, and Carya cordiformis). We fitted the results by linear model and tested the feasibility of μCT technology in quantifying the vessel size of broadleaved species. We found that the results of the two methods for measuring vessel size were highly similar (R2=0.98). The goodness of fit of the vessel diameter results measured by the two methods for the ring-porous wood species (C. cordiformis, R2=0.98; F. americana, R2=0.96; Q. rubra, R2=0.99) was higher than that of the diffuse-porous wood species (B. papyrifera, R2=0.88; O. virginiana, R2=0.73; A. saccharum, R2=0.68; P. grandiden-tata, R2=0.88). The goodness of fit of small vessels (diameter≤200 μm, R2=0.94) measured by the two methods was higher than that of large vessels (diameter>200 μm, R2=0.92). Thus, the μCT technique provided a new non-destructive detection method for quantifying xylem vessels of broadleaved tree species.
在细胞尺度上定量分析导管特征,对于揭示植物对环境的适应策略具有重要意义。直接打磨样品并结合体视显微镜成像技术是目前研究木质部解剖结构(针叶树管胞和阔叶树导管)的主要方法之一,但仍不可避免损伤木质部细胞,限制了对木质部细胞真实解剖结构的认识。本研究选取了加拿大魁北克南部的糖枫树、北美白桦、美洲白蜡树、美洲铁木、大齿杨、苦味山核桃、北美红橡7个阔叶树种,应用计算机显微断层扫描技术(μCT)和体视显微镜法分别测量各树种的导管直径和面积,采用线性模型对两种方法的测量结果进行数据拟合,探讨采用μCT量化阔叶树导管大小的可行性。结果表明: 对所测定的7个树种,应用两种方法测量导管大小的结果高度相似(R2=0.98)。环孔材树种应用两种方法测量的导管直径结果拟合优度(苦味山核桃R2=0.98,美洲白蜡树R2=0.96,北美红橡R2=0.99)高于散孔材树种(北美白桦R2=0.88,美洲铁木R2=0.73,糖枫树R2=0.68,大齿杨R2=0.88)。应用2种方法测量小导管(直径≤200 μm,R2=0.94)的结果拟合优度高于大导管(直径＞200 μm,R2=0.92)。μCT技术为量化阔叶树种木质部导管提供了一种无损检测新途径。.