Soil fungal community characteristics vary with bamboo varieties and soil compartments

Effect of applying oyster shell powder on soil properties and microbial diversity in the acidified soils of pomelo garden

The application of oyster shell has recently been used to increase soil pH in Southern China. However, little is known about causal shifts in the rhizosphere microbial community of pomelo trees, especially in orchards that have experienced natural accumulation of heavy metals over many years due to continuous fertilization and soil acidification. This study evaluated the effects of oyster shell powder applied for 1 year (T1), 2 years (T2) and 3 years (T3), alongside a control group with no soil amendments (Control; CK), on soil acidification and microbial diversity. Our findings demonstrated that the application of oyster shell significantly increased soil pH and reduced the concentrations of heavy metals such as thallium (Tl), chromium (Cr), and manganese (Mn). Illumina sequencing-based community analysis revealed that oyster shell application significantly increased the alpha diversity indices of both bacterial and fungal communities and influenced their distribution in the soil. Notably, all oyster shell-treated groups (T1-T3) showed significantly higher relative abundances of beneficial microbes (e.g., Nitrolancea, Vicinamibacterales) and those involved in carbohydrate degradation and nitrogen fixation compared to the control. Conversely, the relative abundances of Acidibacter and Chujaibacter (associated with heavy metal degradation and soil-borne diseases), Trichoderma and Acremonium (plant-beneficial fungi), as well as functionally annotated groups linked to nitrogen assimilation and pathotrophic modes (predicted via FUNGuild analysis), decreased significantly. Our results suggest that the application of oyster shell powder amendments contributes to improved soil properties and microbial environments; however, the effects on soil nitrogen cycling and fungal function are complex, warranting further research.

Moso bamboo (Phyllostachys edulis) expansion enhances soil pH and alters soil nutrients and microbial communities

Amid global environmental concerns, the issue of bamboo expansion has garnered significant attention due to its extensive and profound impacts on the ecosystems. Bamboo expansion occurs in native and introduced habitats worldwide, particularly in Asia. However, the effects of bamboo expansion on soil pH, nutrient levels, and microbial communities are complex and vary across different environments. To address this knowledge gap, we conducted a meta-analysis with 2037 paired observations from 81 studies. The results showed that soil pH increased by 6.99 % (0-20 cm) and 4.49 % (20-40 cm) after bamboo expansion. Notably, soil pH increased more in the coniferous forest with bamboo expansion than in the broadleaf forest. Soil pH progressively increased over time since the establishment of bamboo stands. The extent of soil pH elevation was significantly positively correlated with the proportion of bamboo within the forest stand and mean annual solar radiation. In contrast, it was significantly negatively correlated with the mean annual temperature. The elevation of pH is closely related to expansion stage and expanded forest type rather than primarily shaped by climatic factors across a large scale. We also found that bamboo expansion into coniferous forests brought about a notable 14.14 % reduction in total nitrogen (TN). Varied expansion stages resulted in TN reductions of 6.88 % and 7.99 % for mixed forests and bamboo stands, respectively, compared to native forests. Pure bamboo stands exhibited a remarkable 30.39 % increase in ammonium nitrogen and a significant 21.12 % decrease in nitrate nitrogen compared to their native counterparts. Furthermore, bamboo expansion contributed to heightened soil fungal diversity. Taken together, our findings highlight that bamboo expansion leads to an increase in soil pH and alters soil N components and fungal microbial communities, providing valuable insights for future ecological conservation and resource management.

Glomeromycota associations with bamboos (Bambusoideae) worldwide, a qualitative systematic review of a promising symbiosis

Background

Around the world, bamboos are ecologically, economically, and culturally important plants, particularly in tropical regions of Asia, America, and Africa. The association of this plant group with arbuscular mycorrhizal fungi belonging to the phylum Glomeromycota is still a poorly studied field, which limits understanding of the reported ecological and physiological benefits for the plant, fungus, soil, and ecosystems under this symbiosis relationship.

Methods

Through a qualitative systematic review following the PRISMA framework for the collection, synthesis, and reporting of evidence, this paper presents a compilation of the research conducted on the biology and ecology of the symbiotic relationship between Glomeromycota and Bambusoideae from around the world. This review is based on academic databases enriched with documents retrieved using different online databases and the Google Scholar search engine.

Results

The literature search yielded over 6,000 publications, from which 18 studies were included in the present review after a process of selection and validation. The information gathered from the publications included over 25 bamboo species and nine Glomeromycota genera from eight families, distributed across five countries on two continents.

Conclusion

This review presents the current state of knowledge regarding the symbiosis between Glomeromycota and Bambusoideae, while reflecting on the challenges and scarcity of research on this promising association found across the world.