Casuarina glauca grows in coastal areas suffering long-term damage due to high salt stress. Arbuscular mycorrhizal fungi (AMF) can colonize their roots to alleviate the effects of salt stress. However, the specific molecular mechanism still needs to be further explored. Our physiological and biochemical analysis showed that Rhizophagus irregularis inoculation played an important role in promoting plant growth, regulating ion balance, and changing the activity of antioxidant enzymes. Transcriptome analysis of roots revealed that 1827 differentially expressed genes (DEGs) were affected by both R. irregularis inoculation and NaCl stress. The enrichment of GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) showed that most of these DEGs were significantly enriched in ion transport, antioxidant enzyme activity, carbohydrate metabolism, and cell wall. HAK5, KAT3, SKOR, PIP1-2, PER64, CPER, GLP10, MYB46, NAC43, WRKY1, and WRKY19 were speculated to play the important roles in the salt tolerance of C. glauca induced by R. irregularis. Our research systematically revealed the effect of R. irregularis on the gene expression of C. glauca roots under salt stress, laying a theoretical foundation for the future use of AMF to enhance plant tolerance to salt stress.

Casuarina glauca is an important coastal protection forest species, which is exposed to high salt stress all year round. Arbuscular mycorrhizal fungi (AMF) can promote the growth and salt tolerance of C. glauca under salt stress. However, the effects of AMF on the distribution of Na⁺ and Cl⁻ and the expression of related genes in C. glauca under salt stress need to be further explored. This study explored the effects of Rhizophagus irregularis on plant biomass, the distribution of Na⁺ and Cl⁻, and the expression of related genes in C. glauca under NaCl stress through pot simulation experiments. The results revealed that the mechanisms of Na⁺ and Cl⁻ transport of C. glauca under NaCl stress were different. C. glauca took a salt accumulation approach to Na⁺, transferring Na⁺ from roots to shoots. Salt accumulation of Na⁺ promoted by AMF was associated with CgNHX7. The transport mechanism of C. glauca to Cl⁻ might involve salt exclusion rather than salt accumulation, and Cl⁻ was no longer transferred to shoots in large quantities but started to accumulate in roots. However, AMF alleviated Na⁺ and Cl⁻ stress by similar mechanisms. AMF could promote salt dilution of C. glauca by increasing biomass and the content of K⁺, compartmentalizing Na⁺ and Cl⁻ in vacuoles. These processes were associated with the expression of CgNHX1, CgNHX2-1, CgCLCD, CgCLCF, and CgCLCG. Our study will provide a theoretical basis for the application of AMF to improve salt tolerance in plants.

Poplars can be harmed by poplar canker. Inoculation with mycorrhizal fungi can improve the resistance of poplars to canker, but the molecular mechanism is still unclear. In this study, an aseptic inoculation system of L. bicolor–P. trichocarpa–B. dothidea was constructed, and transcriptome analysis was performed to investigate regulation by L. bicolor of the expression of genes in the roots of P. trichocarpa during the onset of B. dothidea infection, and a total of 3022 differentially expressed genes (DEGs) were identified. Weighted correlation network analysis (WGCNA) was performed on these DEGs, and 661 genes’ expressions were considered to be affected by inoculation with L. bicolor and B. dothidea. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that these 661 DEGs were involved in multiple pathways such as signal transduction, reactive oxygen metabolism, and plant-pathogen interaction. Inoculation with L. bicolor changed the gene expression pattern of the roots, evidencing its involvement in the disease resistance response of P. trichocarpa. This research reveals the mechanism of L. bicolor in inducing resistance to canker of P. trichocarpa at the molecular level and provides a theoretical basis for the practical application of mycorrhizal fungi to improve plant disease resistance.

Aims This study explored the specific molecular mechanism of Laccaria bicolor to help Populus trichocarpa resist infection by Botryosphaeria dothidea. Methods and Results Transcriptome technology was used to sequence P. trichocarpa under disease stress, and a total of 6379 differentially expressed genes (DEGs) were identified. 536 new DEGs were induced by L. bicolor during the infection of B. dothidea. L. bicolor helps to prevent and alleviate the infection of B. dothidea by regulating related genes in the cell wall pathway, signal transduction pathway, disease-resistant protein synthesis pathway, and antioxidant enzyme synthesis pathway of P. trichocarpa. Conclusion The inoculation of L. bicolor can regulate the expression of genes in the cell wall pathway and enhance the physical defense capabilities of plants. Under disease stress conditions, L. bicolor can regulate signal transduction pathways, disease-resistant related pathways and reactive oxygen species (ROS) clearance pathways to help P. trichocarpa alleviate the disease. Significance and Impact of the Study The research reveals the mechanism of L. bicolor inducing resistance to canker of P. trichocarpa from the molecular level and provides a theoretical basis for the practical application of mycorrhizal fungi to improve plant disease resistance.

This study investigated the differences in rhizosphere soil properties and their associations with microbial communities across eight Coffea arabica cultivars cultivated under uniform conditions at the Kangping Education and Research Base in Pu’er, Yunnan. We assessed arbuscular mycorrhizal fungi (AMF) colonization and spore density, analyzed soil chemical properties—including pH, organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP), available potassium (AK), and slowly available potassium (SK)—and characterized microbial communities via high-throughput sequencing. The findings of this study demonstrate that coffee variety significantly influences the contents of available nutrients (AN, AP, AK) and OM in the rhizosphere soil. Sequencing indicated that Ascomycota dominated the fungal community, Chloroflexi and Proteobacteria were the primary bacterial phyla, and Glomus and Sclerocystis were the predominant AMF genera. Analysis of alpha diversity showed that in the bacterial community, S8 exhibited the highest diversity and richness, while S6 showed the lowest. For the fungal community, S6 had the highest diversity, S2 displayed the highest richness, and S5 showed the lowest values for both diversity and richness. Within the AMF community, S8 demonstrated the highest diversity, S7 exhibited the highest richness, and S6 had the lowest diversity and richness values. Overall, bacterial diversity surpassed fungal diversity. Redundancy analysis identified AK as a common key factor influencing both bacterial and fungal communities. Besides AK, OM and TN were also significant drivers for the fungal and bacterial communities, respectively, while the AMF community was most strongly associated with SK