Coix seed has traditionally been used in traditional Chinese medicine to fortify the spleen and inhibit dampness, and has shown anticancer effects in human

Background: Azolla is a small floating fern living in symbiosis with nitrogen-fixing cyanobacteria and provides a variety of important ecosystem benefits. Previous studies have presented that Azolla harbors diverse bacteria that may play a key role in host fitness and productivity. However, the characteristics of endophytic bacteria inhabiting the phyllosphere of different species of Azolla have not yet been fully understood. Results: In this study, the 16S ribosomal DNA (rDNA) V5-V7 region of bacteria was determined by Illumina high-throughput sequencing platform to study the diversity and richness of endophytic bacterial communities in the phyllosphere of five Azolla species collected from different countries. A total of 1150 operational taxonomic units (OTUs) were detected for the endophytic bacteria community. According to the α diversity indices, the diversity of bacteria was ordered as Azolla imbricata > A. pinnata > A. filiculoides > A. mexicana > A. caroliniana. The PCoA results displayed that the bacterial communities of A. mexicana and A. caroliniana shared the highest similarity, followed by the similarity between A. pinnata and A. imbricata, and they were significantly distinct from the community of A. filiculoides. The dominant bacteria of Azolla mainly belonged to the phylum of Proteobacteria, followed by Actinobacteria, Chlorobillobacteria, and Firmicutes. In detail, the relative abundance of Proteobacteria in A. imbricata was 52.23%, whereas it was more than 80.00% in the other four species of Azolla. Notably, Herbaspirillum (45.91%, 44.08%) and Methylophilus (29.97%, 37.96%) were the main genera inhabiting A. mexicana and A. caroliniana respectively. Ferrovibrio (18.54%) and Rhizobium (16.68%) were the dominant genera inhabiting A. filiculoides. The group of unidentified genera (41.63%, 44.92%) consisted most of the bacteria in A. imbricata and A. pinnata respectively. Further analysis suggested that the significant different bacteria identified in LDA Effect Size analysis existed Azolla species-specific patterns. Conclusions: In summary, all results suggested that the diversity and composition of the endophytic bacterial communities were different in Azolla species.

Background Azolla is a small floating fern living in symbiosis with nitrogen-fixing cyanobacteria and provides a variety of important ecosystem benefits. Previous studies have presented that Azolla harbors diverse bacteria that may play a key role in host fitness and productivity. However, the characteristics of endophytic bacteria inhabiting the phyllosphere of different species of Azolla have not yet been fully understood. Results In this study, the 16S ribosomal DNA (rDNA) V5-V7 region of bacteria was determined by Illumina high-throughput sequencing platform to study the diversity and richness of endophytic bacterial communities in the phyllosphere of five Azolla species collected from different countries. A total of 1150 operational taxonomic units (OTUs) were detected for the endophytic bacteria community. According to the α diversity indices, the diversity of bacteria was ordered as Azolla imbricata > A. pinnata > A. filiculoides > A. mexicana > A. caroliniana. The PCoA results displayed that the bacterial communities of A. mexicana and A. caroliniana shared the highest similarity, followed by the similarity between A. pinnata and A. imbricata, and they were significantly distinct from the community of A. filiculoides. The dominant bacteria of Azolla mainly belonged to the phylum of Proteobacteria, followed by Actinobacteria, Chlorobillobacteria, and Firmicutes. In detail, the relative abundance of Proteobacteria in A. imbricata was 52.23%, whereas it was more than 80.00% in the other four species of Azolla. Notably, Herbaspirillum (45.91%, 44.08%) and Methylophilus (29.97%, 37.96%) were the main genera inhabiting A. mexicana and A. caroliniana respectively. Ferrovibrio (18.54%) and Rhizobium (16.68%) were the dominant genera inhabiting A. filiculoides. The group of unidentified genera (41.63%, 44.92%) consisted most of the bacteria in A. imbricata and A. pinnata respectively. Further analysis suggested that the significant different bacteria identified in LDA Effect Size analysis existed Azolla species-specific patterns. Conclusions In summary, all results suggested that the diversity and composition of the endophytic bacterial communities were Azolla species-specific.

Background: Azolla is a versatile aquatic fern that is rich in nutrients and possesses valuable antibacterial components, making it a useful green manure and medicinal raw plant material. However, the growth of Azolla is affected by microorganisms under different environmental conditions, the investigation on the interaction between microorganisms and Azolla is one of the crucial projects for Azollaexploration and application. Results: In this study, we cultivated two different Azolla species, Azolla imbricata (Aim) and Azolla pinnata (Api), under identical condition to investigate their respective incidence rates. Metagenome analysis of phyllosphere microorganisms was performed to uncover the interaction between Azollaand microorganisms. Our results revealed significantly higher incidence rates in Aim compared to Api. The microbiological community taxonomy showed a predominance of Proteobacteria phylum and Burkholderiales order, with higher proportions in the Aim group. Conversely, the Api group had higher proportions of Cyanobacteria phylum, Nostocales order, Nostocaceae family, and Trichormusgenus. Moreover, pathogenic bacteria exhibited a higher relative abundance in the Aim group. We further analyzed significant differences in KEGG pathways between the two groups and identified the top 10 enriched pathways. Additionally, according to the resistance gene analysis results, five resistant genes showed different patterns between Api and Aim groups. Expect AAC6-IIa, the other five resistant genes had a higher abundance in Aim than in Api. Conclusions: The greater disease susceptibility of Aim compared to Api may be linked to the microbial community structure of the two species. The variations in microbial community structure could be influenced by the antibacterial components present in Api, whereas Aim may lack or have lower levels of these antibacterial components.These findings provide insights into the microorganisms-Azolla interaction, aiding the development of strategies to enhance Azolla growth and utilization.

Background: The aquatic fern Azolla grows rapidly, produces nutrient-rich biomass, and adapts well ecologically due to symbiotic interactions with phyllospheric microorganisms. Azolla imbricata (Aim) and Azolla pinnata (Api) are valuable for biofertilization and phytoremediation, with their ecological differences potentially influenced by species-specific microbial partnerships. This study examines their phyllospheric microbiomes under controlled conditions to explore adaptive strategies. Method and Results: High-throughput metagenomic sequencing identified 10,857 bacteria, 986 eukaryotes. Proteobacteria dominated, particularly Burkholderiales, with higher abundance in Aim. Api exhibited greater Cyanobacteria abundance, especially Nostocaceae (genus Trichormus). Streptophyta constituted over 90% of fungal communities in both species. LEfSe analysis highlighted unique taxa in each species, including enriched Magnoliopsida and Bacillariophyta in Aim, while Api had more Marchantia and Streptophyta. KEGG pathway analysis identified ribosome, oxidative phosphorylation, photosynthesis, quorum sensing, and two-component systems among the most enriched pathways. Resistance gene analysis showed Aim had higher levels of cmlA9, qacEdelta1, tetD, and ANT3-Ii-AAC6-IId_fusion_protein, while Api had more AAC6-IIa. Conclusions: Aim’s enrichment in Proteobacteria may enhance resilience, while Api’s nitrogen-fixing Cyanobacteria suggest distinct nitrogen management. Functional and resistance gene differences highlight ecological adaptability, providing insights for optimizing Azolla’s agricultural potential.