Diversity and Co-Occurrence Patterns of microbial Communities in the Fertilized Eggs of Thitarodes Insect, the Implication on the Occurrence of Chinese cordyceps

Abstract

Background The large-scale artificial cultivation of Chinese cordyceps has not been widely implemented because the crucial factors triggering the occurrence of Chinese cordyceps have not been fully illuminated. Methods In this study, the bacterial and fungal structure of fertilized eggs in the host Thitarodes collected from 3 sampling sites with different occurrence rates of Chinese cordyceps (Sites A, B and C: high, low and null Chinese cordyceps, respectively) were analyzed by performing 16S RNA and ITS sequencing, respectively. And the intra-kingdom and inter-kingdom network were analyzed. Results For bacterial community, totally 4671 bacterial OTUs were obtained. α-diversity analysis revealed that the evenness of the eggs from site A was significantly higher than that of sites B and C, and the dominance index of site A was significantly lower than that of sites B and C ( P < 0.05). β-diversity analysis showed that the differences of bacterial community among the eggs from the three sampling sites were significantly different. OTU1 ( Wolbachia ) was the overwhelming predominant bacteria in the eggs from sites B and C. Although OTU4 ( Spiroplasma ) was detected in minor abundances, it showed distribution preference in the fertilized eggs from site A. For fungal community, totally 3318 fungal OTUs were obtained. Difference analysis showed significant differences among the three sites, while the differences were not as significant as that of bacterial community. In addition, ten fungal genera in the three most concerned Cordyceps families (Clavicipitaceae, Cordycipitaceae and Ophiocordycipitaceae) were detected in the fertilized eggs, while the most approved anamorph ( Hirsutella ) of Chinese cordyceps wasn’t discovered. Intra-kingdom (fungi) network analysis revealed more positive correlations and average degrees at sites A, and Inter-kingdom network analysis revealed more positive and negative correlations at sites A. Discussion The microbial community, especially the bacterial community in the fertilized eggs, might be significantly related with the occurrence of Chinese cordyceps, and Wolbachia might be the most significant microorganism negatively related with the occurrence. A closer correlation of the microbial community, especially closer fungal positive correlation, in the fertilized eggs might help for the occurrence of Chinese cordyceps.

The Bacterial and Fungal Gut Microbiota of the Greater Wax Moth, Galleria mellonella L. Consuming Polyethylene and Polystyrene

“…This approach takes into account synergic effects that could arise from the joint metabolic activities of bacteria and fungi in relation to the environment (e.g., Cucini et al, 2020 ). It has been previously used to describe multi-kingdom ensembles and their behavior under different conditions, in insects of economic importance ( Guo et al, 2020 ), in ruminants ( Pitta et al, 2016 ), and in humans ( Godoy-Vitorino et al, 2018 ). In our study, it helped to identify five taxa that co-occurred in all treatments and individuals, and thus may be participating in core processes.…”