Succession of Fungal Community during Outdoor Deterioration of Round Bamboo

Abstract

Bamboo’s mechanical and aesthetic properties are significantly influenced by fungi. However, few studies have been conducted to investigate the structure and dynamics of fungal communities in bamboo during its natural deterioration. In this study, fungal community succession and characteristic variations of round bamboo in roofed and unroofed environments over a period of 13 weeks of deterioration were deciphered using high-throughput sequencing and multiple characterization methods. A total of 459 fungal Operational Taxonomic Units (OTUs) from eight phyla were identified. The fungal community’s richness of roofed bamboo samples showed an increasing trend, whereas that of unroofed bamboo samples presented a declining trend during deterioration. Ascomycota and Basidiomycota were the dominant phyla throughout the deterioration process in two different environments: Basidiomycota was found to be an early colonizer of unroofed bamboo samples. Principal Coordinates Analysis (PCoA) analysis suggested that the deterioration time had a greater impact on fungal community variation compared to the exposure conditions. Redundancy analysis (RDA) further revealed that temperature was a major environmental factor that contributed to the variation in fungal communities. Additionally, the bamboo epidermis presented a descending total amount of cell wall components in both roofed and unroofed conditions. The correlation analysis between the fungal community and relative abundance of three major cell wall components elucidated that Cladosporium was negatively correlated with hemicellulose in roofed samples, whereas they presented a positive correlation with hemicellulose and a negative correlation with lignin in unroofed samples. Furthermore, the contact angle decreased during the deterioration process in the roofed as well as unroofed samples, which could arise from the degradation of lignin. Our findings provide novel insights into the fungal community succession on round bamboo during its natural deterioration and give useful information for round bamboo protection.

Temporal Dynamics of Fungal Communities in Alkali-Treated Round Bamboo Deterioration under Natural Weathering

“…The highest values of bamboo fungal ACE index and Chao 1 index were observed in HY13, with 56.84 and 57.7, respectively. This result was different from our previous research on fresh round bamboo, which showed that community richness presented increasing and declining trends in roofed and unroofed groups, respectively, during deterioration [29]. One of the reasons is that the immersion of an alkaline solution was able to remove some nutrient sources for fungi, such as soluble starch and sugars, forming a barren and harsh environment for microorganisms.…”

“…This result indicates that, compared with different rainfall environments, different deterioration times make a greater contribution to the variation of fungal communities and thus have a greater impact on the succession of fungal communities on round bamboo. This result was in accordance with our previous research on fresh round bamboo [29]. In addition, samples of roofed groups (i.e., H9-1, H9-2, and H9-3) were clustered into one branch, while samples of unroofed groups (i.e., HY9-1, HY9-2, and HY9-3) were clustered into another branch in UPGMA dendrograms, which illustrated that rainfall, to some extent, contributes to this divergence.…”

“…Cladosporium dominated the entire deterioration process in both roofed and unroofed groups, especially in H9 (92.52%) and HY13 (61.53%). This result was consistent with our previous research on fresh round bamboo [29]. Cladosporium is a large genus of dematiaceous hyphomycetes fungus and has a broad lifestyle due to its strong adaptation to different environments [53].…”

“…Moreover, the relative abundance of saprotrophs in roofed groups was lower than that of unroofed groups. This result was different from our previous study on fresh round bamboo, which showed an opposite appearance [29]. Tervonen et al [71] revealed that pH was one of the major drivers in the communities of saprotrophic fungi, and pH was positively correlated with the species richness of saprotrophic fungi in the range of pH 3.0-5.0.…”

“…In our previous research, we investigated the succession of fungal communities on fresh round bamboo during the natural deterioration of three months [29]. Nevertheless, alkali-treated round bamboo was more commonly used than fresh round bamboo in the daily lives of individuals.…”