Jie Tang

Introduction: Peach trees are often threatened by various diseases during cultivation. Methods: This study took the roots and rhizosphere soil of diseased peach trees as the research objects and investigated the effects of single and combined treatments of Bacillus (including Bacillus velezensis and Bacillus subtilis ) and graphene oxide (GO) on peach trees. Results: The results showed that compared with the diseased control group, the single treatments of Bacillus velezensis (Group V) and Bacillus subtilis (Group S) significantly reduced soil pH (to 8.55 and 8.35, respectively) as well as the contents of calcium (Ca) and zinc (Zn), enhanced organic carbon accumulation (up to 26.43 g/kg), bringing these key indicators close to the rhizosphere levels of healthy peach trees (CK1: pH 8.42, organic carbon (OC) 24.10 g/kg). Additionally, these treatments restored nutrient cycling functions by increasing microbial diversity. The effect of GO treatment showed a concentration dependence: high-concentration GO increased the microbial Shannon index and available phosphorus content, while low-concentration GO inhibited the accumulation of available nitrogen. Among the combined treatments, the combination of Bacillus velezensis and GO, by synergistically regulating the contents of Ca and available nitrogen, restored rhizosphere microecological homeostasis more significantly than the combination involving Bacillus subtilis . Discussion: This study reveals the mechanism by which the “microbe-GO” combination achieves rhizosphere ecological remediation through the “element balance - microbial community function” linkage and provides a theoretical basis and technical strategies based on healthy microecological targets for the prevention and control of soil-borne diseases in peach trees.

The insect gut contains a complex and diverse microbial community, and the composition of the insect gut microbial community is influenced by multiple factors such as the host’s genetics, dietary habits, and the external environment. The host’s immune system maintains the stability and balance of the microbial community through a number of mechanisms. The microorganisms in this community play key roles in the nutrient metabolism, detoxification, immune regulation, development, and behaveior of insects. In recent years, the relevant literature has reported advances in the study of insect gut microbes, indicating the potential applications of insect gut microbes in several fields. The aim of this review is to provide a comprehensive overview of the current information on the structure of insect gut microbial communities and complex host–microbe–environment interactions. The diversity of insects’ gut microbial communities and the functions of their gut microbes are revealed. By studying insect gut microbial communities, we can gain insights into the functions of these microbes in the host and explore the causal relationships between them and the host’s physiology and behavior. This will not only help us to understand the mechanism of action of the microbiome, but also provide a basis for the development of innovative biotechnology based on insect gut microbes. This research has significant theoretical value in academia and also has a wide range of applications in agriculture, environmental protection, industrial production, and healthcare.

Members of the families Thermosynechococcaceae and Thermostichaceae are well-known unicellular thermophilic cyanobacteria and a non-thermophilic genus Pseudocalidococcus was newly classified into the former. Analysis of the codon usage bias (CUB) of cyanobacterial species inhabiting different thermal and non-thermal niches will benefit the understanding of their genetic and evolutionary characteristics. Herein, the CUB and codon context patterns of protein-coding genes were systematically analyzed and compared between members of the two families. Overall, the nucleotide composition and CUB indices were found to differ between thermophiles and non-thermophiles. The thermophiles showed a higher G/C content in the codon base composition and tended to end with G/C compared to the non-thermophiles. Correlation analysis indicated significant associations between codon base composition and CUB indices. The results of the effective number of codons, parity-rule 2, neutral and correspondence analyses indicated that mutational pressure and natural selection primarily account for CUB in these cyanobacterial species, but the primary driving forces exhibit variation among genera. Moreover, the optimal codons identified based on relative synonymous codon usage values were found to differ among genera and even within genera. In addition, codon context pattern analysis revealed the specificity of the sequence context of start and stop codons among genera. Intriguingly, the clustering of codon context patterns appeared to be more related to thermotolerance than to phylogenomic relationships. In conclusion, this study facilitates the understanding of the characteristics and sources of variation of CUB and the evolution of the surveyed cyanobacterial clades with different thermotolerance and provides insights into their adaptation to different environments.

Background: The transcription factors (TFs) in thermophilic cyanobacteria might represent a uniquely evolved gene repertoire in light of the strong selective pressure caused by hostile habitats. Understanding the molecular composition of the TF genes in thermophilic cyanobacteria will facilitate further studies regarding verifying their exact biochemical functions and genetic engineering. However, limited information is available on the TFs of thermophilic cyanobacteria. Herein, a thorough investigation and comparative analysis were performed to gain insights into the molecular composition of the TFs in 22 thermophilic cyanobacteria. Results: The results suggested a fascinating diversity of the TFs among these thermophiles. The abundance and type of TF genes were diversified in these genomes. The identified TFs are speculated to play various roles in biological regulations. Further comparative and evolutionary genomic analyses revealed that HGT may be associated with the genomic plasticity of TF genes in Thermostichus and Thermosynechococcus strains. Comparative analyses also indicated different pattern of TF composition between thermophiles and corresponding mesophilic reference cyanobacteria. Moreover, the identified unique TFs of thermophiles are putatively involved in various biological regulations, mainly as responses to ambient changes, may facilitating the thermophiles to survive in hot springs. Conclusion: The findings herein shed light on the TFs of thermophilic cyanobacteria and fundamental knowledge for further research regarding thermophilic cyanobacteria with a broad potential for transcription regulations in responses to environmental fluctuations.

Thermophilic cyanobacteria play a crucial role as primary producers in hot spring ecosystems, yet their microbiological, taxonomic, and ecological characteristics are not extensively studied. This study aimed to characterize a novel strain of thermophilic cyanobacteria, PKUAC-SCTA174 (A174), using a combination of traditional polyphasic methods and modern genomic-based approaches. The study included 16S rRNA-based phylogeny, ITS secondary structure prediction, morphological and habitat analyses, as well as high-quality genome sequencing with corresponding phylogenomic analyses. The results of the 16S rRNA, 16S-23S ITS secondary structure, morphology, and habitat analyses supported the classification of the strain as a member of a novel genus within the family Oculatellaceae, closely related to Albertania and Trichotorquatus. Genomic analysis revealed the presence of a sophisticated carbon-concentrating mechanism (CCM) in the strain, involving two CO₂ uptake systems NDH-I₃, and NDH-I₄, three types of bicarbonate transporters (BCT1, bicA, sbtA,) and two distinct putative carboxysomal carbonic anhydrases (ccaA1 and ccaA2). The expression of CCM genes was investigated with a CO₂ shift experiment, indicating varying transcript abundance among different carbon uptake systems. Based on the comprehensive characterization, the strain was delineated as Thermocoleostomius sinensis, based on the botanical code. The study of the complete genome of strain A174 contributes valuable insights into the genetic characteristics of the genus Thermocoleostomius and related organisms and provides a systematic understanding of thermophilic cyanobacteria. The findings presented here offer valuable data that can be utilized for future research in taxogenomics, ecogenomics, and geogenomics.