Large scale exploration reveals rare taxa crucially shape microbial assembly in alkaline lake sediments.

Alkaline lakes are extreme environments inhabited by diverse microbial extremophiles. However, large-scale distribution patterns, environmental adaptations, community assembly, and evolutionary dynamics of microbial communities remain largely underexplored. This study investigated the characteristics of microbial communities on rare and abundant taxa in alkaline lake sediments in west and northwest China. We observed that abundant taxa varied significantly with geographical distance, while rare taxa remained unaffected by regional differences. The assembly process of abundant taxa was influenced by dispersal limitation, whilst rare taxa were predominantly driven by heterogeneous selection. Network analysis indicated that rare taxa as core species for community interactions and community stability. Rare taxa exhibited higher speciation and transition rate than abundant taxa, serving as a genetic reservoir and potential candidates to become abundance taxa, highlighting their crucial role in maintaining microbial diversity. These insights underscore the significant influence of rare taxa on ecosystem biodiversity and stability in alkaline lakes.

MicroRNA257 promotes secondary growth in hybrid poplar.

Populus, a significant fast-growing tree species with global afforestation and energy potential, holds considerable economic value. The abundant production of secondary xylem by trees, which serves as a vital resource for industrial purposes and human sustenance, necessitates the orchestration of various regulatory mechanisms, encompassing transcriptional regulators and microRNAs (miRNAs). Nevertheless, the investigation of microRNA-mediated regulation of poplar secondary growth remains limited. In this study, we successfully isolated a novel microRNA (Pag-miR257) from 84 K poplar and subsequently integrated it into the 35 S overexpression vector. The overexpression of Pag-miR257 resulted in notable increases in plant height, stem diameter, and fresh weight. Additionally, the overexpression of Pag-miR257 demonstrated a significant enhancement in net photosynthetic rate. The findings from the examination of cell wall autofluorescence indicated a substantial increase in both xylem area and the number of vessels in poplar plants overexpressing Pag-miR257. Furthermore, the cell wall of the Pag-miR257 overexpressing plants exhibited thickening as observed through transmission electron microscopy. Moreover, the Fourier Transforms Infrared (FTIR) analysis and phloroglucinol-HCl staining revealed an elevation in lignin content in Pag-miR257 overexpressing poplar plants. The findings of this study suggest that microRNA257 may play a role in the control of secondary growth in poplar stems, thereby potentially enhancing the development of wood engineering techniques for improved material and energy production.

A new illudane sesquiterpene from the edible fungus Pholiota nameko.

Fungi have different genetic expression abilities and biosynthetic pathways under different cultivation conditions, which can produce various secondary metabolites. The "one strain many compounds" strategy is used to activate silent biosynthetic genes of fungi to produce various compounds, which is an effective method. In order to discover various new compounds in the edible fungus Pholiota nameko, a fermentation strategy involving precursor feeding and enzyme inhibitor addition has been employed. A new illudane sesquiterpene (1), along with one known indole diterpenoid alkaloid, cladosporine A (2) were isolated from the extracts of liquid culture of P. nameko. The new compound was identified by combination of 1D and 2D NMR, MS, optical rotation, and ECD calculations. We conducted experiments on the cytotoxicity of all isolated compounds on three cancer cell lines, but we did not observe any significant cytotoxicity (IC50 > 40 µM).

iTRAQ-based proteomic analysis of heteromorphic leaves reveals eco-adaptability of Populus euphratica Oliv.

BACKGROUND: Heterophylly is regard as adaptation to different environments in plant, and Populus euphratica is an important heterophyllous woody plant. However, information on its molecular mechanism in eco-adaptability remains obscure. RESULTS: In this research, proteins were identified by isobaric tags for relative and absolute quantitation (iTRAQ) technology in lanceolate, ovate, and dentate broad-ovate leaves from adult P. euphratica trees, respectively. Besides, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate and peroxidase activity in these heteromorphic leaves were investigated. A total number of 2,689 proteins were detected in the heteromorphic leaves, of which 56, 73, and 222 differential abundance proteins (DAPs) were determined in ovate/lanceolate, dentate broad-ovate/lanceolate, and dentate broad-ovate/ovate comparison groups. Bioinformatics analysis suggested these altered proteins related to photosynthesis, stress tolerance, respiration and primary metabolism accumulated in dentate broad-ovate and ovate leaves, which were consistent with the results of physiological parameters and Real-time Quantitative PCR experiments. CONCLUSION: This research demonstrated the mechanism of the differential abundance proteins in providing an optimal strategy of resource utilization and survival for P. euphratica, that could offer clues for further investigations into eco-adaptability of heterophyllous woody plants.

Conjoint Analysis of Genome-Wide lncRNA and mRNA Expression of Heteromorphic Leavesin Response to Environmental Heterogeneityin Populus euphratica.

Heterophylly is the phenomenon of leaf forms varying along the longitudinal axis within a single plant. Populus euphratica, a heterophyllous woody plant, develops lanceolate leaves and dentate broad-ovate leaves on the bottom and top of the canopy, respectively, which are faced with different intensities of ambient solar radiation. However, the mechanism of the heteromorphic leaf response to the microenvironment in P. euphratica remains elusive. Here, we show that the dentate broad-ovate leaves have advantages in tolerating high light intensity, while lanceolate leaves are excellent at capturing light. Compared with lanceolate leaves, more trichomes, higher stomatal density, thicker lamina, and higher specific leaf weight were observed in dentate broad-ovate leaves. Furthermore, high-throughput RNA sequencing analysis revealed that the expression patterns of genes and long noncoding RNAs (lncRNAs) are different between the two heteromorphic leaves. A total of 36,492 genes and 1725 lncRNAs were detected, among which 586 genes and 54 lncRNAs were differentially expressed. Based on targets prediction, lncRNAs and target genes involved in light adaption, protein repair, stress response, and growth and development pathways were differentially expressed in heteromorphic leaves, 10 pairs of which were confirmed by quantitative real-time PCR. Additionally, the analysis of interactions indicated that lncRNA-mRNA interactions were involved in the response to the microenvironment of heteromorphic leaves. Taken together, these results suggest that the morphological features and joint regulation of lncRNA-mRNA in heteromorphic leaves may serve as survival strategies for P. euphratica, which could lead to optimal utilization of environmental factors.